Combustions is essentially the reasons why fuel powered cars are able to move. and for this to happen, the correct ration of fuel to air needs to be mixed. This is where the throttle comes in. and without a properly functioning throttle position sensor, this is not possible. Keep reading to learn how to troubleshoot the sensor when it malfunctions.
Signs of a faulty throttle position sensor Toyota Tacoma
Below are the most common symptoms of a bad throttle position sensor. Address throttle position sensor problems as soon as possible to avoid risks of accidents and damaging your delicate engine.
Check Engine Warning Light
The throttle position sensor is a key component of the overall internal combustion process. If this sensor goes bad, your engine will ultimately fail to produce sufficient power to accommodate your acceleration needs.
The engine control unit will detect this problem when it exists and then activate the Check Engine warning light on the dashboard. That way, you will be aware that your engine has some kind of problem that needs to be addressed.
Common diagnostic trouble codes related to the TPS include: P0121, P0122, P0123, P0124, P2135, and P2138.
Engine Rough Idling
When you stop or park your vehicle somewhere, its idle RPM should be somewhere in the vicinity of 600 to 900 RPM. If you notice the engine RPM below or above that range while your vehicle is stopped or parked, then you have a rough or erratic idling problem with your engine.
This may be due to a bad throttle position sensor if you’ve experienced some of the other symptoms on this list.
Excess Fuel Consumption
Since the throttle position sensor has a major effect on proper air/fuel mixture for burning, inaccurate readings can cause too much fuel to injected into the combustion chamber. This will cause a rich air/fuel ratio which will result in poor fuel economy.
In addition, other sensors depend on accurate readings from the TPS. When that doesn’t happen, those sensors will often compensate for too little or too much airflow. The end result is usually the need to go fill up on gas more frequently than usual.
Acceleration Changes/ Weak Acceleration
A bad throttle position sensor means the engine control unit cannot manage the throttle position properly. The engine won’t be able to receive the proper amount of air because of this. Whenever you go to accelerate your vehicle under these conditions, the acceleration will be very weak.
You’ll be lucky if you can move the vehicle faster than 30 miles per hour. This will cause you to consume a lot of gasoline, and ultimately ruining your car’s fuel economy.
One very strange acceleration problem that can occur is increased acceleration without stepping on the gas pedal. You could be driving along on the road, and your car will just speed up on its own out of the blue. This can obviously be very dangerous.
Out of all the acceleration problems that can occur, this particular one is a clear indicator that the throttle position sensor is to blame.
When these sensors start to go bad, your car’s computer receives incorrect data, leading to your engine getting incorrect inputs. Different parts try to overcompensate for these deviations.
For instance, if the engine is receiving more air than it needs, the computer will compensate by injecting extra fuel to rebalance the air-fuel mixture. Therefore, in most cases when your sensor goes bad, your car will be noticeably consuming more fuel than usual.
Engine Rough Idling Or Sudden Stalling
Faulty throttle position sensors can cause rough idling due to fluctuating airflow. If you see your car misfiring, idling rough, or stalling out while you drive, it is highly likely that you’re having a faulty throttle position sensor.
Start-up Issues
Also due to fluctuating airflow, a bad throttle position sensor may cause all sorts of power issues. Your engine may start up but it will have little to no power, runs briefly, but then dies out.
Otherwise, it can also cause your car to have spontaneous surges during accelerations for no apparent reasons, or cause weaker accelerations than usual.
Abrupt bucking or jerking
The throttle position sensor sometimes fails in a way that causes the signal sent to the engine’s computer to be sporadic. The effect will be similar to when you are quickly applying and releasing the gas pedal.
Difficulty In Switching Gears
If the throttle position sensor fails it can cause automatic transmission shifting problems. The throttle position sensor is important for proper automatic transmission control because it immediately establishes the driver’s intent, and transfers this information to the Transmission Control Module.
Without such correct and timely transfer of data, you will experience delay and/or difficulty in switching gears.
Your car goes into limp-home mode
In some models, a failing or faulty throttle position sensor can cause the engine to go into “limp-home mode”. In this situation, you will experience reduced engine power, and you may be stuck in a higher gear.
This is a safety feature designed to get you off the highway and allow you to drive a few extra miles to the nearest repair shop. Once this happens, do not drive any more than needed and get repairs immediately.
Toyota Tacoma throttle position sensor connector location
A throttle position sensor (TPS) is a sensor used to monitor the air intake of an engine. The sensor is usually located on the butterfly spindle/shaft, so that it can directly monitor the position of the throttle.
The throttle position sensor is a vital part of the fuel management system installed on the throttle body. Its primary job is to ensure the correct mixture of fuel and air is delivered through the fuel injection system, through the intake, and into the combustion chamber.
Like any other sensor, the TPS is designed to collect data. In this case, it monitors the position of the throttle in relation to the RPM, or how fast the engine turns over. The data collected and signal it produces is sent to the ECU or ECM, which then breaks down the data to change the fuel to air mixture.
Can you drive Toyota Tacoma with faulty throttle position sensor?
Driving with a faulty throttle position sensor will have a serious impact on fuel economy, but can also lead to lasting engine damage and dangerous situations.
There are many things that may happen when your throttle position sensor is bad. These can range from your car stalling to your transmission not shifting properly. Though this sensor is small, it can lead to many annoying and dangerous problems. When it is not working correctly, the amount of air entering your intake will not be properly regulated. Once the TPS goes bad, it will need to be replaced with a new sensor.
Linking the gas pedal and the engine, the throttle position sensor has to work flawlessly to ensure full control over the vehicle.
The throttle position sensor plays an important role in a car or truck’s overall performance. This device, which feeds data to the vehicle’s computer system and allows it to determine the correct mix of air to fuel for the engine, can either malfunction or receive incorrect information from the throttle components.
Normal Operation
The throttle position sensor relays information about the throttle’s status to the vehicle’s engine computer, which then compares the information with other factors such as speed, vehicle load and engine temperature in its commands to the vehicle. The throttle position sensor usually relies on a potentiometer, sometimes accompanied by a switch, that sends signals of varying voltage to indicate relative throttle position. Throttle position sensors can fail or wear out just like any other engine component. Sometimes improper service causes the sensor to malfunction. A sensor problem will usually activate a check-engine light, but the car may send out its own cry for help in the form of performance problems.
Sensor Failure
According to Wells Manufacturing Corporation, a throttle position sensor may malfunction from its initial installation. This installation sets the performance parameters for the sensor, and an incorrect setting will cause the computer to request a less-than-optimum fuel mixture, resulting in poor engine performance from the beginning of the car’s life.
Common causes of throttle position sensor failure in Toyota Tacoma
Most of the time, the sensor simply wears out with age. Like other auto parts, these sensors do not last forever.
Exposure to excess dust, dirt, oil, or water can cause them to fail early. They will usually last for 100,000 miles or more, although they can fail early if your car operates in extreme conditions.
Code errors can cause your throttle position sensor to work erratically or incorrectly.
Intermittent Errors
A throttle position sensor must issue a steady stream of data to the computer to account for each throttle adjustment. If the throttle position sensor fails to relay a “throttle closed” signal to the computer, the car will stall or experience start-up problems. The car may also hesitate, or misfire while in gear, if the throttle position sensor develops a loose connection, according to Wells Manufacturing Corporation.
“Always Closed” or “Always Open” Errors
Some malfunctions can cause the throttle position sensor to regard the throttle as always open or always closed. A short in the sensor, for instance, will produce the “always-open” error, resulting in an overly rich fuel mixture. If the sensor circuit remains continuously open, the computer will interpret this as an “always-closed” signal and create an overly lean fuel mixture.
Troubleshooting and Repair
Before troubleshooting the throttle position sensor itself, Auto Media recommends checking the throttle components for proper function. If the throttle stop or cables keep the throttle forced open, the sensor cannot tell the computer to put the car into idle.
An automotive scan tool offers an easy way to detect throttle position sensor issues. While some of these tools can only interpret check-engine codes, others can read the actual data stream issuing from the sensor.
Depressing the throttle slowly will cause a bad potentiometer to throw an error code. A faulty sensor usually requires replacement, but if the problem lies elsewhere in the engine, repairs to those components may solve the problem.
How to replace throttle position sensor Toyota Tacoma
Throttle Position Sensor Safety
Just because it seems like an easy job, there’s no reason to skip out on safety.
- Make sure you’ve disconnected the battery before starting work. It’s no fun finding out that you’re dealing with live wires the hard way.
- Take care of your hands and eyes here by wearing safety glasses and gloves.
- Park your car on level ground anytime you’re going to be working under the hood. The last thing you want is to have to chase a car down the street.
- If you don’t have a safe parking space or garage to work in, try to move to a quiet parking lot or place away from traffic and moving vehicles.
Items needed
- Work gloves
- Safety glasses
- Screwdriver set
- Voltmeter
- Parts List
- Replacement throttle position sensor
You might need your VIN to find the correct throttle position sensor, especially if your make/model came with different powertrain options from the factory.
Organizing your tools and gear so everything is easily reachable will save precious minutes waiting for your handy-dandy child or four-legged helper to bring you the sandpaper or blowtorch. (You won’t need a blowtorch for this job. Please don’t have your kid hand you a blowtorch—Ed.)
You’ll also need a flat workspace, such as a garage floor, driveway, or street parking. Check your local laws to make sure you’re not violating any codes when using the street because we aren’t getting your ride out of the clink.
Disconnect the Battery
Before you start work, disconnect the battery’s negative terminal cable. This will prevent unwanted shocks to you and damage to other components under the hood.
Unplug Old Sensor
Once you’ve located the sensor’s position, you should be able to unplug the wiring harness that connects it to the vehicle’s computer system. Carefully unplug it, taking notice of any clips or connectors that need to be moved.
Remove Mounting Screws
Once it’s disconnected, you should be able to remove the screws that hold the sensor in place. Keep track of them in case you need to reuse them to install the new one.
Remove Old Sensor
Pull out the old sensor and dispose of it according to local regulations. While removing the faulty sensor, take careful note of where each part and component is, so that you will be able to reassemble the new sensor easily later on.
First, disconnect your negative battery cable before removing the sensor. This helps you avoid the risk of electrical shock or causing an error code on your Engine Control Module. Your throttle position sensor should be attached using electrical connectors. These connectors are easy to remove using the tab on the side.
Once the electrical connectors are removed, look for the mounting screws on your sensor. Carefully unscrew and remove your throttle position sensor.
Mount and Screw in New Sensor
Reversing the process, screw in the new sensor in the spot that the old one was pulled from. To make sure you buy the correct replacement sensor for your vehicle, consult your owner’s manual when shopping for a new one.
Install your new sensor by repeating the removal steps backwards. Start by installing the sensor using the mounting screws. Then, connect your sensor to your vehicle’s electrical system using a convenient electrical connector. You should be able to easily push it together and hear a distinct click. Check to ensure a firm connection.
Connect your battery and now check if the replacement works. Start your car and test the idle and acceleration to see if the previous starting, idling and acceleration problems are resolved. Your car should idle smoothly and accelerate with adequate power.
Depending on your vehicle and the sensor you’ve installed, you may need to manually adjust the sensor. Other options allow automatic adjustments.
Re-Plug Wiring Harness
Carefully re-plug the wiring harness into the new sensor, taking care to pay attention to clips and connectors that need to be aligned for proper installation.
Reconnect Battery Cables
Reconnect the negative battery terminal.
How to Repair A Throttle Position Sensor
Once you’ve established the issue is with your sensor, check if the problems could be the result of faulty or loose wiring. Just like any other electrical wiring, your throttle position sensor is susceptible to corrosion and faulty connections.
Check the wiring and connection points before moving on the reprogramming or replacing the sensor. Clean any corrosion and build-up with a quality carburettor cleaner and soft brush.
First, locate the throttle position sensor. It should be mounted to your throttle body, which is on top of your engine.
The throttle position sensor is a small sensor that’s about the size of your key fob. It has an electrical connector attached to it that normally houses three wires. On most engines, there are two smaller screws that secure it to the throttle body.
Once you’re aware of a bad throttle position sensor symptoms and have performed the above quick check, you can choose to have a professional check it out and replace the faulty sensor.
While completely replacing your sensor may be the best way to avoid future issues, some issues can be easily fixed by reprogramming or repairing your sensor. This step can also be necessary when you install a new sensor. Learn this handy maintenance tip to save yourself time and trouble going to the mechanics.
How To Reset the Throttle Position Sensor in a Toyota
Resetting is sometimes all that is required to get rid of throttle position sensor symptoms and restore your sensor to proper function. The easiest way to reprogram or reset your throttle position sensor is to unhook the negative cable from your battery for up to five minutes or to remove the fuse for your Engine Control Module.
This is important, as it helps you avoid the risk of electrical shock or causing an error code on your Engine Control Module.
Don’t attempt this if you’re uncomfortable working with electricity, as removing the wrong fuse or cable from your battery could be dangerous. Sometimes, you’ll need professional software to reprogram your sensor. In this case, this task is best done by a professional mechanic.
Otherwise, sometimes your sensor is irreparably damaged. It needs to be replaced in order to restore your engine to its optimal efficiency.
How to Reset Throttle Position Sensor
If you’ve properly identified the throttle position sensor as the cause of problems in your Toyota, then follow these steps on how to reset it. However, if you’re uncertain, take a look at the sections explaining how the throttle position sensor works, and what the common signs of failure are.
Depending on the method, you’ll need either a set of wrenches, or a fuse pullers.
First Throttle Sequence
Before you complete the following steps, warm up the engine to the optimal running temperature. You can do this by leaving it to idle while adding some gas to prevent stalling, or driving it if it’s safe.
You won’t need any tools, and this method works well in situations where the battery has died or you needed a jump start.
- Put the key in the ignition.
- Turn the key to the On position, without cranking the engine. Wait a few seconds, then turn it off.
- Repeat the second step.
- Crank the engine.
- Pull the parking brake.
- Set the gear lever in Drive.
- Wait 5-10 minutes.
Second Throttle Sequence
Just like the first sequence, the second does not require any tools or knowledge, and the engine doesn’t have to be warmed up. It works on Toyota Tacoma between the years 2005 and 2015 but could work on other models as well.
- Put the key in the ignition.
- Turn the key to the on position, without cranking the engine.
- Slowly press on the gas pedal, hold for three seconds, and release slowly. Repeat three times.
- Put the key in Off position and take it out.
- Wait 5-10 minutes.
Disconnecting the Battery
The first method is a very simple, two-step process. Lift up the hood and locate the car battery. Use the appropriate wrench to disconnect the cables from the battery, and leave it for a few minutes.
How To Reset The Throttle Position Sensor In a Toyota
Reattach the wires, making sure not to overtighten and break the clamps, and you’re done! The process gives the electronic system enough time to fully discharge and then reboot, just like a smartphone or a laptop.
Resetting the Fuse
This is a rare occurrence, but sometimes taking the fuse out and putting it back in might be enough to fix the TPS issues. The fuse box location depends on the type of vehicle, so you’ll need the owner’s manual to find it.
Once you’ve gained access to it, reference the manual again to find the corresponding fuse, take it out using fuse pullers, see if it’s in good condition, then plug it back in.
There is still a chance that the sensor can be reset, but if not, you’ll need to get a replacement to ensure safe engine operation. Because of the complexity of the task, I cannot properly instruct you on how to replace the sensor yourself. If you feel like you’re up for the challenge, take a look at the following video for additional information:
How Does the Throttle Position Sensor Work?
Throttle position sensor, or TPS for short, is an important part of the fuel management system and directly links the gas pedal and the engine. As the driver applies pressure on the gas pedal, TPS converts that information into valve movement, dictating the amount of air flowing into the engine’s intake manifold.
Original potentiometric throttle position sensors were very rudimentary, but modern non-contact units include inductive, magnetoresistive, and hall effect sensors, to name a few.
The added complexity leads to better performance and fuel economy, but in case of failure repairing it proves to be a difficult task, so the common course of action is to replace it completely.
Throttle Position Sensor Troubleshooting Procedure
NOTE: The following operations are applied in a typical three state throttle valve switch. In some cases the idle switch and the full load switch can be connected separately. Also there are separate idle and full load switches. In some Rover models the throttle valve switch is located on the accelerator pedal. Regardless of the location of the switch, the verification procedure is performed similarly for all types of sensors.
Check TS Voltage
- The three wires entering the throttle switch coupling are grounding, idle mode signal and full load signal.
- Connect the negative terminal of a voltmeter to the engine ground.
- Determine the ground, idling and full load terminals of the sensor.
- Turn on the ignition, but do not start the engine.
- Connect the positive terminal of a voltmeter to the wire, connected to the idle signal contact of the throttle switch.
- Voltmeter must read voltage of 0V. If it reads voltage 5.0V, loosen the screws and adjust the switch so that the voltmeter reads zero voltage.
NOTE: In some cars the throttle valve switch could not be adjusted.
Check TS resistance
- Disconnected the throttle connector.
- Connect ohmmeter between the ground and the idle mode terminals.
- When the throttle valve switch is turned on, the ohmmeter should read resistance around 0 Ω.
- Slowly open the throttle valve and when the switch opens the resistance should be equal to infinity and remain the same even if the throttle is fully opened.
- Connect ohmmeter between the ground and the full load mode terminals.
- When the throttle switch is closed, ohmmeter must read circuit break (infinite resistance).
- Slowly open the throttle valve. When the switch opens it should click and the resistance should remain equal to infinity. When the throttle valve opening angle becomes greater than 72 degrees, the resistance will be equal to 0 Ω.
- If the switch does not work in the described way, and the turning on and turning off cannot be regulated by bending the levers driving the throttle valve, most likely the throttle switch is defective.
Possible damages in TS:
1) Can not get voltage 0V (closed throttle valve)
- Check the throttle valve state.
- Check the switch connection to the ground.
- Take measurements of the switch resistance.
- If the voltage is normal with closed throttle valve, sharply open the throttle valve, switch must click, and the voltage should rise up to 5.0V.
2) Voltage is low or missing (the throttle valve is opened)
- Check whether the idle mode switch terminal is not connected to ground.
- Disconnect the switch connector and check for presence of 5.0V voltage in the idle mode contact. If there is no voltage, carry out the following checks:
- check the integrity of the idle mode signal wire between the switch and the onboard controller;
- If the switch wires are good, check all supply and ground connections of the onboard controller. If they are correct, the fault may be in the onboard controller.
3) The voltage is normal (throttle valve is opened)
- Connect the positive terminal of a voltmeter to the wire, connected to the full load mode switch contact.
- When the throttle valve is in idle state or slightly open, the voltmeter should read voltage of 5.0V.
4) Voltage is low or missing (the throttle valve is closed or slightly open)
- Check the ground connection.
- Check whether the full load mode contact of the throttle switch is not connected to ground.
- Disconnect the switch connector. Check the presence 5.0V voltage in the full load mode contact of the connector. If there is no voltage carry out the following checks:
- check the integrity of the idle mode signal wire between the switch and the onboard controller;
- If the switch wires are good, check all supply and ground connections of the onboard controller. If they are correct, the fault may be in the onboard controller.
5) The voltage is normal (the throttle valve is closed or slightly open)
- Fully open the throttle valve. When the opening angle becomes more than 72 degrees, the voltage should drop to zero. If the voltage does not drop most likely the throttle switch is malfunctioning.
Check TPS voltage
- Connect the negative terminal of a voltmeter to the engine ground.
- Determine the ground, idling and full load terminals.
NOTE: Most throttle potentiometers have three terminals, but some may have and extra contacts, which function as throttle switches. If there is such a contact, it must be checked as described above for throttle switch.
- Connect the voltmeter positive terminal to the wire connected to the contact signal from the throttle valve potentiometer.
- Turn on the ignition, but do not start the engine. In most systems the voltage reading should be less than 0.7V.
- Open and close the throttle valve several times, by checking the smoothness of the rising voltage.
Check the resistance of the TPS
- Connect an ohmmeter between the potentiometer wiper and the reference voltage terminal or between the potentiometer wiper and the ground.
- Open and close the throttle valve several times and check the smoothness of resistance variation. If the potentiometer resistance is infinite or zero, this indicates a malfunction.
- Exact values of the throttle potentiometer resistance are not shown. One of the reasons is that many manufacturers do not publish control data. The fact that the resistance of the potentiometer is kept within limits is less important than the proper operation of the potentiometer, i.e. resistance smooth change when moving the throttle valve.
- Connect an ohmmeter between the ground and the reference voltage terminals. The resistance must be constant.
- If the resistance is infinite or is low, the potentiometer must be replaced.
Possible damages in TSP Chaotic output signal
- Chaotic output signal is observed when the voltage signal changes rapidly, drops to zero and disappears.
- When the throttle valve potentiometer output signal is chaotic, a defective potentiometer is usually the reason for this. In this case, the potentiometer must be replaced.
Missing voltage signal
- Check the presence of reference voltage (5.0V) on the throttle potentiometer power terminal.
- Check the condition of the potentiometer grounding contact.
- Check the signal wire connecting the throttle potentiometer to the onboard controller.
- If the power supply and ground are bad, check the wires integrity between the potentiometer and the onboard controller.
- If the potentiometer wires are good, check all supply and ground connections of the onboard controller. If they are correct, most likely reason is the onboard controller itself.
Check this too: Signs That You Have A Bad Or A Failing Throttle Body
The output signal or the reference voltage is equal to the battery voltage
- Check for short-circuit in the wire connected to the positive terminal of the car battery or the power supply wire.