If your Toyota Fortuner has a humming noise at high speed, it can be distracting and, depending on the cause, dangerous.

We’ve outlined the most common reasons why a humming noise in your vehicle gets louder with speed. We’ve also provided an audio sample of each issue to help determine what’s causing the hum. 

Toyota Fortuner Humming at High-Speed: Quick Info

How to Tell the Difference Between a Bad Wheel Bearing and Bad Tire

Bad wheel bearings and bad tires have a similar sound. You can tell them apart in most cases by doing this simple test on your Toyota Fortuner:

1. Drive your vehicle at the slowest speed it takes to reproduce the humming noise.
2. Wiggle the steering wheel back and forth. You’re looking to change your Fortuner’s load balance from one side to the other.
3. Did the sound change as you moved the wheel? If it did, your vehicle likely has a faulty wheel bearing. If it didn’t change, it’s likely a tire-related problem.

If you suspect a bad wheel bearing, jack your Fortuner up and free-turn each wheel. If one sounds gritty, that wheel bearing will likely need replacing.

1. Defective Wheel Bearing

A defective wheel bearing is a very common reason your Fortuner will make a humming noise while driving. Here’s what a bad wheel bearing sounds like:

A bad wheel bearing can cause a humming sound. If your Fortuner has a worn wheel bearing, the sound will be slightly more high-pitched than a tire issue (you can play that sound below).

You can test all four wheel bearings when the vehicle is stationary. Jack up each wheel and spin it freely. If the wheel sounds “gritty” and is hard to turn, you likely found the humming sound’s cause.

You can also use the method outlined above, where you rock your Fortuner while it’s moving to see if there is a change in pitch. If there is, you’re usually looking at a worn wheel bearing and not a bad tire.

2. Tire Issues

Here’s the sound of a cupped tire:

If your Toyota Fortuner is suffering from uneven tire wear, you should be able to pick up the noise while driving around 30 MPH with it getting louder as you accelerate.

With uneven tire wear, you may also notice:

Wheel Out of Balance

If your Fortuner’s wheels are not correctly balanced, it can cause a humming noise when driving.

Tires are balanced with wheel weights when a new tire is installed. Balancing corrects any vibration before the tires go on the vehicle. Take a look behind the wheels. You can usually tell if a wheel weight fell off.

See the wheel weight above? Depending on where they are needed, they can be on the front or back of your Fortuner’s wheels. You’ll likely see the spot where the wheel bearing was.

Cupping

Tires that are “cupped” or “scalloped” have uneven tread wear across the tire. Run your hand along the tread. If it’s cupped badly enough, you’ll feel the unevenness.

The following suspension issues usually cause cupping:

• Bad shocks/struts
• Bad ball/cv joints
• Poor wheel alignment

If you find cupping on the inside tread of your Fortuner’s tire, suspect an issue with the wheel alignment.

If the cupping is on the outside tread, it still could be an alignment issue. But it’s more likely your Toyota Fortuner has a suspension problem. Here’s more from Atlantic Motor car on cupping. Or, you can watch the video below. It picks up at the exact point where you can see what cupped tread looks like.

Large Tire Tread

A humming noise is normal if you’ve recently replaced your Fortuner’s tires with an aggressive tread.

Off-road and snow tread tires are notorious for making a loud humming sound.

Other Causes

A bad wheel bearing or suspension issue are the most common causes of humming when driving on the highway in the Toyota Fortuner. Here are some other things that can cause noise while at speed:

• Brakes– If the brakes have worn past their squealers, they’ll make noise at highway speed. The problem is, the noise is AWFUL. It feels like grinding. It can come and go depending on the wheel’s angle and the vehicle’s speed. 
• Power Steering– A bad power steering pump can make a humming sound. The only problem is that it should be heard at any speed. You may only be noticing it while your Fortuner is moving. Try revving the engine while in Park and seeing if that creates the humming noise.

Conclusion

You can do a few simple tests to figure out what is causing a humming noise while driving at high speed in your Toyota Fortuner. It’s not a breakdown risk, but you can still end up stranded if the wheel bearing or suspension component causing the hum fails.

P0088 is a common OBD2 trouble code that can occur in the Toyota Fortuner. In layman’s terms, it indicates that your SUV’s fuel pressure is too high.

While P0088 is a generic code, repair steps will vary depending on your Fortuner’s model year, engine type, and how it regulates fuel pressure.

P0088 Definition: Fuel Rail/System Pressure – Too High

P0088 is a generic powertrain code that indicates a fuel pressure issue. This code is set when your Fortuner’s PCM detects too much pressure in the fuel system.

Fuel Rail/System Pressure

The purpose of the pressure monitoring system is to help the engine run by monitoring the fuel pressure from the fuel injection system. Too much fuel can lead to just as many problems as no fuel.

Too High

If the fuel pressure is too high (the voltage value coming from the fuel pressure sensor is over the maximum value), it signals your Fortuner’s PCM to display code P0088. Several components make up the fuel system. If any of them are faulty, it could cause a code P0088.

The main components that can fail and cause P0088 are the fuel pump, fuel pressure regulator, and fuel pressure sensor. Knowing how your SUV’s fuel pressure is regulated can help you figure out the faulty component.

There are two ways that an engine can have its fuel pressure regulated.

1. The first way is to use a fuel pressure regulator, which returns the extra pressure to the fuel tank.
2. The other way is that the fuel pressure is regulated by the fuel pressure sensor, as it works with the PCM. The fuel pump can adjust to the needs of the engine directly, with no regulator needed. The fuel pressure sensor signals the pressure in the fuel rail to the PCM. If it’s not working correctly, the engine may stall or run rough.

P0088 Symptoms: Toyota Fortuner

There will almost ALWAYS be symptoms associated with P0088 if the fuel pressure is incorrect. There may not be any symptoms if the fuel pressure sensor is bad.

Here are the common symptoms associated with P0088 in the Toyota Fortuner:

• Slow/no start
• Decreased fuel mileage
• Misfiring (you’ll likely see code P0300, focus on P0088 first)
• Fouled spark plugs
• Stalling
• Black exhaust smoke

P0088 Causes 

Here are the most common causes of P0088 in the Toyota Fortuner:

• Bad fuel pressure regulator
• Bad fuel pressure sensor
• Bad fuel pump
• Wiring issues at the fuel pressure sensor
• PCM

Toyota Fortuner P0088 Diagnosis

While several things can cause the P0088 code in the Toyota Fortuner, here’s a good order to diagnose them in:

Inspect the Fuel Pressure Sensor Wiring

Start here (particularly if your Fortuner is running fine).

Take a look at the fuel pressure sensor wiring. Make sure that it is not burnt, cracked, or frayed. Due to its location, damage to the harness is very common. It’s not uncommon for a rodent to nest around the intake, particularly in the wintertime.

Make sure that the harness is plugged into the sensor tightly and that there are no damaged pins inside the connector. If there are, you’ll need to repair or replace the harness.

Check the Fuel Pressure

Be careful when checking your Fortuner’s fuel pressure. It’s always best to do it with the engine cold. Make sure you have a fire extinguisher ready in case the fuel sprays. Do not connect or disconnect the fuel pressure gauge with the engine on.

The next course of action when diagnosing P0088 is to test the actual fuel pressure at the fuel rail. You’ll need a manual fuel pressure testing gauge. That’s not a tool that most Shadetree mechanics have, you can usually rent one or borrow one from the local parts store.

You’ll need to look up the exact fuel pressure for your vehicle and engine combination. If the fuel pressure checks out, you likely have a bad fuel pressure sensor.

If the fuel pressure is too high, you’ll need to replace the fuel pressure regulator.

Check the Fuel Pump

A returnless fuel pump can cause P0088. You’ll need to verify what type of fuel system your particular Toyota Fortuner has.

Using a multimeter, check the resistance of the fuel pump by connecting the positive lead to the positive terminal on the pump and the negative lead to the negative terminal.

Conclusion

Fixing P0088 in the Toyota Fortuner involves determining whether or not the fuel pressure is really too high or if the sensor is bad. If the pressure is too high, it can only be a few things that cause the issue.

P0152 is a common OBDII code that occurs in many vehicles, including the Toyota Fortuner. It indicates that the bank 2 sensor 1 O2 sensor is reporting a voltage level that is higher than its normal operating range.

P0152 Definition: O2 Sensor – High Voltage – B2S1

O2 Sensor

Oxygen sensors are responsible for metering the exhaust as it exits the engine. This allows the PCM (Powertrain Control Module) to adjust the air/fuel ratio constantly, which helps your Fortuner’s engine run at optimum efficiency.

High Voltage

P0152 is triggered when your Fortuner’s PCM detects the following conditions:

• The voltage at the B2S1 O2 sensor remains above the voltage threshold for 20 seconds or more.
• The air-fuel sensor stays in rich biased mode for too long.

There are also some less likely problems that can cause P0152. We’ll go over those below.  

Bank 2 Sensor 1

• Bank 2 is the side of the engine with the second cylinder.
• Sensor one is the first sensor in line as the exhaust leaves the head. It’s on or right after the exhaust manifold.

Toyota Fortuner P0152 Symptoms

If your Fortuner has P0152, there are usually noticeable symptoms. They include:

• Rough running engine
• Smelly exhaust
• Service engine soon light on
• Poor MPG

Most of the time, it’s not a breakdown risk. But, like anything that causes the service engine soon light to come on, it is a good idea to have it fixed as soon as possible.  A poor air fuel mixture going through the catalytic converter can damage it.

Toyota Fortuner P0152 Causes 

Here are the most common issues that cause the P0152 code in the Toyota Fortuner. They are presented in order (somewhat) from most to least likely to cause the problem.

• Bad Oxygen Sensor– The O2 sensor itself is one of the most likely reasons that P0152 is triggering your service engine soon light. Although it is a temptation to replace it right away, it wouldn’t hurt to check out the wiring harness around it beforehand.
• Wiring Harness Issues- The wiring that goes to the front and rear oxygen sensors is very susceptible to damage. This is due to the fact that O2 sensors are under the chassis, where they are subject to punishment from road debris, and exhaust heat. Here’s how to find a short in the wiring harness (Youtube).
• Damage to the Terminal– The terminal that the oxygen sensor connects to (the plug) is also relatively susceptible to damage. You’ll want to make sure that there is voltage going to it. There’s more on that directly below.
• Wrong O2 Sensor– If you are getting P0152 after having recently replaced your Oxygen sensor, it may be that the replacement is wrong or bad.

Fortuner P0152 Diagnosis

Here is a fantastic video that covers all aspects of diagnosing the P0152 code:

Swap Test (Easy to Do At Home With Simple Tools)

You can perform the swap test by swapping the bank 1 and bank 2 oxygens sensors. Clear the code and see if it changes to P0132 (the bank 1 side of this code). If it does, you need to replace the oxygen sensor that was just swapped from bank 2.

Using a Multimeter

This video is for P0132, but is completely relevant for P0152

It is possible to diagnose the P0152 with a multimeter. If you use the multimeter, you’ll know whether or not the voltage coming to and from the oxygen sensor is within spec, this can help you determine if it’s your Fortuner’s O2 sensor or wiring harness that’s the issue.

If you don’t have access to a multimeter, it certainly wouldn’t hurt to check the wiring to between the fuse box and the Oxygen sensor first. If it ends up being a wiring issue, it’ll save you money over buying an unnecessary O2 sensor.

You can also use a voltage test light to determine whether or not the oxygen sensor is getting any voltage at all (they’re about $5 at Walmart).

If it’s not getting any voltage, attach the test light to the harness plug and shake the wiring a little bit. If the light comes on, even for a second, you know that you have a short circuit causing the P0152 trouble code.

Conclusion

Good luck finding whatever caused P0152 in your Toyota Fortuner. It’s usually caused by a bad O2 sensor. Since there are two “banks”, you can use the swap test for a quick and easy diagnosis.

P0725 is a common OBD2 code that can occur in the Toyota Fortuner. It indicates an issue with the engine speed sensor input circuit (which measures the engine speed at the input shaft and helps the PCM determine when and how hard to shift the transmission).

It’s a generic code, which means it has the same meaning for the Fortuner as it would any other vehicle. Exact repair steps will depend on your Toyota’s model year and transmission type.

P0725 Definition: Engine Speed Input (Sensor) – Circuit Malfunction

Engine Speed Input Sensor

The engine speed input sensor is responsible for relaying data to your Fortuner’s PCM on how fast the engine turns. It can be referred to as the transmission input speed sensor, input speed sensor, or engine speed input sensor.

On most Transmissions, it screws into the case near the front of the input shaft. A relcutor wheel turns with the input shaft, and the engine input speed sensor uses an electromagnetic field to measure how fast it is turning.

Circuit Malfunction

Your Toyota Fortuner’s engine speed input circuit sends data that it receives from the input speed sensor back to the PCM in the form of a voltage value. It’ll compare this value to the engine RPM, output speed sensor, and throttle position.

When the voltage value is not theoretically correct when compared to the other sensors, P0725 is stored in the PCM’s memory.

Toyota Fortuner P0725 Symptoms

While P0725 is not typically a full breakdown risk, there will usually be very difficult to drive. Here are the most common symptoms your Fortuner may experience:

• Check engine light
• Speedometer and tachometer not working properly (or at all)
• Transmission not shifting properly
• Not all gears are available, and harsh shifts (limp mode)

Toyota Fortuner P0725 Causes + Diagnosis

Here are the most common causes of P0725 in the Toyota Fortuner:

Dirty or Low Transmission Fluid

Since P0725 is a transmission-related trouble code. The first thing you should do is check the transmission fluid color. If it’s brown, black, or gray, there could be a transmission problem.

If there are metal flakes in the transmission, it can cause the input speed sensor to stop picking up the reluctor wheel.

Speed Input Sensor Wiring Issue

After confirming that your Fortuner’s transmission fluid is in good shape and properly filled, the next easiest thing to check is the wiring harness coming from the input speed sensor.

Check the harness for cracks or damage. If it appears damaged, replacing it may clear P0725.

Inspect the pins where it plugs into the speed input sensor. If the pins are damaged or corroded, you’ll either need to clean/replace them or repair the harness.

Bad Input Speed Sensor

A bad input speed sensor is the most common cause of P0725. Before replacing it, inspect it to see if there are any metal shavings on the magnetic tip.

Other Causes

Here are some other causes of P0725:

• Transmission Failure: If your Toyota Fortuner has a transmission that is slipping, it can create metallic debris that affects the input speed sensor.
• Bad PCM: This rarely happens but has been known to cause P0725.
• Failing Shift Solenoid(s): You’ll likely see metal debris on the dipstick if this were the case.

Conclusion

While a bad input speed sensor is perhaps the most common cause of P0725 in the Toyota Fortuner, it’s one of many potential causes. Good luck fixing your vehicle.

P0523 is a standard OBD2 trouble code that can occur in the Toyota Fortuner. In layman’s terms, it indicates the signal from the oil pressure sensor is higher than its normal operating range (in terms of voltage).

P0523 is generic (it has the same definition for all vehicles), repair steps will depend on your Fortuner’s model year and the engine equipped.

A bad oil pressure sensor is the most common cause of P0523. However, an oil system issue could trigger this code as well. Don’t assume the sensor is bad until you confirm the oil pressure manually. If there’s an oiling issue, it can cause engine damage or failure.

P0523 Definition: Engine Oil Pressure Sensor/Switch – High Input

Here’s precisely what P0523 is telling you:

Oil Pressure Sensor/Switch

The oil pressure sensor bolts into your Fortuner’s engine and relays the oil pressure reading to the Powertrain Control Module (PCM). It converts the mechanical pressure reading into a voltage value that the PCM understands.

From the PCM, the oil pressure is sent to the oil pressure gauge (or warning light).

High Input

The voltage value is almost at or above its highest possible value (which tells the PCM that the oil pressure level is very high). If the input was low, you’d have P0522.

Toyota Fortuner P0523 Symptoms

Your Fortuner may feel like it’s running and driving fine, but even without symptoms, you shouldn’t drive it with P0523 until you verify the oil pressure is fine.

Here are the most common symptoms associated with P0523:

• Check engine light
• High oil pressure reading on the gauge or the oil pressure light could be on

P0523 Toyota Fortuner Causes

Two things are going on. Either the oil pressure is too high, or there is an issue related to the oil pressure sensor.

Here are the most common causes of P0523 in the Toyota Fortuner and the proper order to check them.

Check the Oil

Verify that the oil level isn’t overly full. Is it sludgy? Is it the proper weight? If you didn’t pour it in yourself, it’s possible that the wrong viscosity was used the last time the oil was changed. Consider this possibility if you got P0523 right after an oil change.

Bad Oil Pressure Sensor – Wiring

If the oil level is correct, it’s not old, and it’s the proper viscosity, it’s time to look at your Fortuner’s oil pressure sensor. A wiring failure is widespread with these sensors due to their proximity to the exhaust.

Inspect the harness for any obvious damage. Look for cracked, broken, burnt, or brittle wiring. Follow the harness as long as you can, but pay particular attention to it within a couple of feet of where it plugs into the head.

Test the Oil Pressure Sensor

You can test the oil pressure switch/sensor with a simple multimeter. The video below will show you how to do it for just about every type of oil pressure sensor.

You could also get a mechanical oil pressure tester from a place like AutoZone or Harbor Freight. They’re usually around $25-$40 and will 100% tell you if you have a real oil pressure problem. That’s about the same price as a new oil pressure sensor, and you’ll be plugging into the same hole anyway.

If the manual oil pressure checks out, you have positive proof that your Fortuner doesn’t have a sensor or wiring issue.

Mechanical Issues

While a bad oil pressure sensor or wiring issue is the most common cause of P0523, it’s not the only one. If your Fortuner has a faulty oil pump or restricted oil passaged can also cause this code. You can verify this with an oil pressure test kit (it’s just a mechanical oil gauge with adapters to fit most makes/models).

Conclusion

While there are a few issues that can cause P0523 in they Toyota Fortuner, start by checking the oil and testing the oil pressure sensor. More often than not, that’ll fix the code. Good luck!

P2279 is a generic OBD-II code. It indicates there is a vacuum leak coming from your Toyota Fortuner’s air intake system. While P2279 is a generic code (it has the same definition for the Fortuner as it would any other vehicle made after 1996), repair steps will vary based on model year and engine.

The most common cause of P2279 is a vacuum leak. If you’ve recently cleaned your air induction system (particularly the throttle blade), the code can appear while the PCM learns to compensate for the extra air now entering the engine at idle.

P2279 Definition: Intake Air System Leak

The intake air system allows air to enter your Fortuner’s engine. The PCM (powertrain control module) monitors the amount of air entering the intake manifold via a MAP (manifold absolute pressure) sensor or a Mass Airflow Sensor.

When the PCM detects that the amount of air entering the engine is greater than the sensors mentioned above indicate, P2279 will be stored in its memory.

P2279 Symptoms: Toyota Fortuner

There are almost always noticeable symptoms when P2279 is present. There are usually symptoms because modern fuel-injected engines (such as the one in your Fortuner) need to maintain the ideal air/fuel mixture of 14.7:1, and when they deviate from that mixture, it really can affect the way they run.

When too much air is getting into the combustion chamber, the air mixture is considered lean. Here are the most common symptoms associated with a lean engine and P2279:

• Lack of power
• Stalling
• Pinging or knocking sounds
• Misfire trouble codes
• Dedicated lean trouble code
• Hissing sound (this indicates an air leak and is good news since noticeable noise is usually pretty easy to track down)
• Surging engine, and your Toyota Fortuner may have a hard time finding idle

Toyota Fortuner P2279 Causes and Diagnosis

While a vacuum leak is the most common cause of P2279, a recently cleaned throttle body can also trigger this code. Your Fortuner’s PCM will need time to adjust for the change in airflow that the cleaning has caused.

If there are any misfire or air-fuel mixture-related codes, focus on P2279 first. These will likely take care of themselves after you find the vacuum leak.

The good news with P2279 is that it is usually pretty easy to track down and fix. Here’s an excellent order to check potential causes.

Listen for a Leak

Remember that P2279 can only be detected where the air is metered. So, there’s no point in checking around anything upstream of the Mass Airflow Sensor.

Open your Fortuner’s hood and listen for an air leak with the engine running. You may get lucky and hear an obvious leak.

If the leak is not so apparent, you can use carb cleaner to find it. You’ll spray a little bit on intake parts, and when the RPM increases, you’ve found the leak.

Start where air enters the engine and work your way back. It’s way more likely that a hose has been compromised than an intake manifold gasket has failed.

Do this when the engine is completely cold, and have a fire extinguisher handy. Proceed at your own risk.

Common Vaccum Leak Points

Here are the most common locations in an engine that can cause P2279 in the Toyota Fortuner:

• Any sensor attached to the intake
• Fuel injector seal (if you have a single-cylinder misfire code, this becomes a real possibility)
• Brittle and broken vacuum hoses
• Power brake booster (the vacuum hose that runs from it to the intake)
• Intake temp sensor

Conclusion

A vacuum leak almost always causes P2279 in the Toyota Fortuner. Testing for it is easy with carb and choke cleaner, but it can be dangerous. If you test with it, make sure the engine is cold and have a fire extinguisher handy.

P0605 is a relatively rare OBD-II trouble code that can occur in the Toyota Fortuner. It indicates that PCM (powertrain control module) is not passing its ROM (read-only memory) self-test when you turn the ignition on.

While P0605 is a generic code (it has the same meaning for any car or truck), it is most frequently seen in Ford and Nissan-made vehicles.

The most common cause of P0605 is a bad PCM. If you’ve recently had your Fortuner’s PCM reflashed and you ended up with P0605, you’ll need to have them repair or replace it.

P0605 Definition: Internal Control Module – ROM Error

Your Fortuner’s PCM uses Read-Only Memory (ROM) to store its operating system, just like your computer keeps its operating system on a hard disk.

Every time you start your engine, the PCM tests its ROM by running the same mathematical calculations. Since ROM is meant to be read and not written to, the value returned from the equation should always be the same number. When it’s not, P0605 is stored, and the check engine light comes on.

Toyota Fortuner P0605 Symptoms

Without fail, there are almost always noticeable symptoms that accompany P0605. Here are the most common ones:

• Transmission may shift erratically
• Limp mode
• Misfiring (you’ll most likely have P0300, random misfire)
• No start
• Dash warning lights

Even if your Fortuner’s engine appears to be running fine, we don’t recommend driving with P0605. The code indicates that there is a serious issue with the PCM. Modern vehicles can’t run or drive at all if the PCM fails.

Toyota Fortuner P0605 Causes and How to Fix

A bad PCM almost always causes P0605, but you should check your Toyota Fortuner’s wiring harness before sending it in for repair.

Bad Wiring Harness

Check the ground to the PCM. You’ll need a printout of the circuit for your particular engine and model year. Make sure that it’s not damaged or corroded. Check that the voltage level going into the PCM is correct. If it’s off, P0605 can be triggered.

PCM Replacement

Unfortunately, replacing the PCM is the most common way to fix P0605. However, replacing it is not as simple as buying a new one online. You need one that is matched to your Fortuner’s engine, transmission, model year, VIN, security system, and more.

A good diagnostic shop (or the dealer) can flash the new PCM and get it right. They can test the wiring. Sometimes, they even are able to save the old PCM.

If you want to try replacing the PCM at home, there are websites online, such as Car Computer Exchange (not an affiliate link), where they can tune it for you based on your VIN. You’ll have to mail in your old PCM.

Conclusion

P0605 is most likely caused by a bad PCM. If you’ve recently had your PCM reflashed, take it back to the shop and let them know you have this code. Good luck fixing P0605 in your Toyota Fortuner!

P0058 is a not too common and OBDII trouble code that occurs in the Toyota Fortuner. It indicates that the heated oxygen sensor (which we’ll be referring to as HO2S a lot) heater control circuit located at B2S2 is sending a signal to the PCM that is outside of its normal operating range. In this case, the signal is higher than it should be.

P0058 should not be considered a breakdown risk. The HO2S in question is downstream of the catalytic converter and is mainly just for emissions purposes. The upstream oxygen sensors do most of the heavy lifting in terms of air/fuel ration confirmation.

P0058 is almost always a bad HO2S or a wiring issue.

Acronyms in this Article:

• HO2S– Heated Oxygen Sensor
• B2S2– Bank 2, Sensor 2
• PCM– Powertrain Control Module (sometimes called ECM)

P0058 Definition: HO2S – Heater Control Circuit High – B2S2

Here are the three parts to the definition of P0058. The first part is the malfunctioning part on your Fortuner, the second part indicates what is wrong, and the third part tells you where the malfunctioning HO2S is located.

HO2S

The heated oxygen sensor measures the exhaust content after it exits the catalytic converter. The PCM uses this data to maintain the proper 14.7:1 air/fuel ratio. But, as stated above, the downstream O2 sensor’s primary function is to measure exhaust gasses exiting the catalytic converter.

Heater Control Circuit High

The heated element within your Toyota Fortuner’s oxygen sensor heats the sensor faster than the exhaust can on its own. This reduces emissions by letting the fuel trim enter closed loop operation more quickly.

In the case of P0058, your Fortuner’s PCM has detected that the heater control circuit resistance is outside the manufacturer’s specified range.

Bank 2 Sensor 2

Bank 2 Sensor 2 is the location of the oxygen sensor. Bank 1 is the side of your Fortuner’s engine with the first cylinder. Bank 2 is usually (but not guaranteed) to be the cylinder head that is a little further back from the engine accessories.

Sensor 2 is the first oxygen sensor “downstream” of the catalytic converter.

P0058 Symptoms: Toyota Fortuner

There usually aren’t any noticeable symptoms for P0058, whatsoever.

P0058 Toyota Fortuner: Causes and Diagnosis

Here are the most common causes of P0058 in the Toyota Fortuner, as well as a decent order to check them in.

1. Check the Wiring on Bank 2 Sensor 2

CHECK THE WIRING HARNESS FOR DAMAGE since P0058 indicates a fault in the heated O2 sensor circuit.

Pay extra close attention to where the harness may have rubbed up against something or has been damaged by road debris. Look for burnt, frail, or damaged wiring. Wiring issues are a VERY COMMON cause for P0058.

Take a look at where your Fortuner’s oxygen sensor plugs into the wiring harness and see if there has been any damage to the pins or if the wiring harness is breaking at the pigtail.

If the pins appear corroded, get some electrical contact cleaner and clean them up. If they are damaged, you will need to repin or replace your wiring harness.

2a. Verify the O2 Sensor is Bad- Swap Test

Since your Fortuner happens to be a V6 or V8 model, you can do the “swap test”

This test involves clearing the codes and seeing if the code “jumps” to bank 1. It’s a great test because it’s foolproof and easy to do.

Here’s how the swap test is done:

• Clear the DTC codes with your scanner.
• Swap the Bank 2 Sensor 2 O2 sensor with the Bank 1 Sensor 2. It’ll be right after the catalytic converter on each side of the exhaust.
• Run your Fortuner’s engine until the check engine light comes back on.
• If the code changes to P0038 (The Bank 1 version of this code), that’s proof enough you need to replace the oxygen sensor you swapped.
• If the code remains P0058, you’ll need to continue pursuing your diagnosis, knowing that both O2 sensors are working fine.

2b. Check the O2 Sensor Heater Resistance

You can test the heater element resistance. This will for sure verify whether the heated element is bad or not.

If there is voltage at the heater circuit, you’ll need to test the ground for resistance. If you find infinite resistance, you’ll need to repair the ground circuit.

This YouTube video can help you learn how to test it.

3. Bad Oxygen Sensor

If the oxygen sensor wiring checked out or the code jumped with the swap test, it’s time to replace the heated oxygen sensor at B2S2. Oxygen sensors go bad all the time. It’s very unlikely that P0058 is caused by a PCM issue.

Conclusion

P0058 in the Toyota Fortuner is almost always caused by a bad wiring harness or heated oxygen sensor. You can do the swap test to easily verify if the O2 sensor is bad or not.

P0056 is a somewhat common O2 sensor-related OBD2 trouble code. It is a generic code, which means it has the same definition for the Toyota Fortuner as it would any other vehicle.

This code is almost always caused by a bad heated oxygen sensor or wiring issue and almost never creates drivability issues.

P0056 should NOT be considered a breakdown risk if it appears by itself. While your Fortuner’s engine relies heavily on the upstream sensor for engine tuning, the downstream O2 sensor is there to verify catalytic converter efficiency.

P0056 Definition: Heater Control – Circuit – B1S2

P0056 indicates there is no signal coming from your Toyota Fortuner’s Bank2 Sensor 2 oxygen sensor’s heater circuit.

The heated element within the B2S2 oxygen sensor heats the sensor faster than the exhaust can. This reduces emissions by letting the fuel trim enter closed loop operation more quickly.

The A/F sensor is responsible for measuring the oxygen content of the exhaust. The PCM uses this data to adjust the air-fuel mixture to the optimal 14.7 parts air to 1 part fuel.

Circuit

In the case of P0056, the PCM has detected a fault in the circuit that activates the oxygen sensors heater.

Bank Two

Bank one is the part of your Fortuner’s engine with the second cylinder. You only need to concern yourself with “banks” if there is more than one cylinder head, and in this case, you do need to determine which bank is bank 2.

Bank one is usually the cylinder head facing a little more forward than the other (toward the engine accessories), while bank 2 will face a little further back. This is a general rule, and manufacturers can determine the cylinder location without any sort of standardized system.

Sensor 2

The second sensor is easier to identify. Start from bank two and follow the exhaust. It’ll be right after the catalytic converter.

Symptoms of P0056 in the Toyota Fortuner

The heated element in the oxygen sensor enables closed-loop operation faster, decreasing engine emissions.

You probably won’t notice any drivability issues with your Fortuner since B2S2 is there to verify the catalytic converter is doing its job.

If your Fortuner had P0050 (the Bank 2 Sensor 1 version of this code), there would be more noticeable symptoms.

Toyota Fortuner: P0056 Causes + Diagnosis

Here are the most common causes of P0056 in the Toyota Fortuner, presented to you in a somewhat proper order of diagnosis:

1. Check the Wiring on Bank 2 Sensor 2

Since the PCM is not getting a response from the heated oxygen sensor circuit, check the wiring harness for damage.

Pay extra close attention to where the harness may have come into contact with something. Look for burnt or damaged wiring. Wiring issues are a VERY COMMON cause for P0056.

The hot exhaust can make the wiring harness brittle, and road debris can damage them.

Take a look at where your Fortuner’s oxygen sensor plugs into the wiring harness and see if there has been any damage to the pins or if the wiring harness is breaking at the pigtail.

If the pins appear corroded, get some electrical contact cleaner and clean them up. If they are damaged, you will need to repin or replace your wiring harness.

2. Check the Fuses and Voltage

Check the heated oxygen sensor fuse to ensure that it has not blown for some reason. Then, verify with the key on that there’s voltage at the B2S2 oxygen sensor. If there is no voltage, you’ll need to find where the short/open is.

If there is voltage at the heater circuit, you’ll need to test the ground for resistance. If you find infinite resistance, you’ll need to repair the ground circuit.

3. Optional – Swap Test

With P0036, you can do the “swap test.” This involves clearing the codes and seeing if the code “jumps” to bank 2. It’s a great test because it’s foolproof and easy.

Here’s how the swap test is done:

• Clear the DTC codes with your scanner.
• Swap the Bank 1 Sensor 2 O2 sensor with Bank 2 Sensor 2’s sensor.
• Run the your Fortuner’s engine until the check engine light comes back on.
• If the code changes to P0036 (The Bank 1 version of this code), that’s proof enough you need to replace the oxygen sensor you swapped.
• If the code remains P0056, you’ll need to continue pursuing your diagnosis, knowing that both O2 sensors are working fine.

4. Bad Oxygen Sensor

If the oxygen sensor wiring checked out or failed the swap test, it’s time to replace the heated oxygen sensor. Oxygen sensors go bad all the time.

Conclusion

P0056 in the Toyota Fortuner is almost always caused by a bad wiring harness or oxygen sensor. Good luck!

P0107 is a relatively common OBD2 trouble code that can occur in the Toyota Fortuner. In plain English, it indicates that the voltage coming from the MAP sensor is below the normal operating range.

P0107 Definition: MAP Sensor – Circuit Low Input

It’s a generic code, so it has the same meaning for the Fortuner as it would any other vehicle.

Here’s the definition of P0107, provided with the understanding it can help make diagnosing it a little bit easier.

MAP Sensor

The MAP (Manifold Absolute Pressure) sensor records the pressure in the intake manifold and reports it to the ECM. It can also be referred to as the barometric pressure sensor as well. For this article, the terms are interchangeable.

Circuit Input Low

The MAP sensor sends the current intake pressure reading to your Fortuner’s ECM in the form of a voltage signal. When the signal is below the normal operating threshold, P0107 will be stored, and the check engine light will come on.

P0107 Symptoms: Toyota Fortuner

With the MAP sensor not sending a proper signal back to the ECM, your Fortuner will probably not run very well: Here are some of the most common symptoms of P0107 you could be observing:

Toyota Fortuner P0107 Causes + Diagnosis

Here are the most common causes associated with P0107 and a proper order to check them in. Your first impulse may be to throw a new MAP sensor into your Fortuner and be done with it. And, if you have the money to throw at the problem, you may very well get lucky.

If you don’t want to make an unnecessary purchase, we’ll go over how to diagnose and test the MAP sensor before you replace it.

Wiring Issues

Before testing the MAP sensor, do a quick inspection of your Toyota Fortuner’s wiring harness. Then, follow the connection from the MAP sensor to where it meets the rest of the harness.

If the wiring is brittle, cracked, exposed, or damaged in any other way, repairing it will likely clear P0107. Also, examine the pins where the MAP sensor plugs into the wiring harness.

Test The MAP Sensor Voltage

Here’s how to go about testing a MAP sensor with a multimeter. You are trying to determine if the voltage going to the MAP sensor is correct and that the voltage leaving it is within range.

If the voltage is OK going to it, but too low coming out, that indicates a bad MAP sensor is causing P0107. If the voltage is lower than 12 volts, that could be a wiring issue.

This video from Ratchets and Wrenches covers exactly how to test the MAP with the multimeter.

Other P0107 Causes

While a bad MAP sensor or wiring issues are far and away the most common reasons you’ll bump into P0107 in the Toyota Fortuner, there are other (less common) causes as well. Here they are:

Conclusion

P0107 in the Fortuner is almost always fixed by replacing the MAP sensor or repairing the wiring harness.