While small and relatively simple, the throttle position sensor (TPS) is a critical component that tells your car’s computer how far you’re pressing the gas pedal, helping control fuel delivery to your engine.
If your TPS fails, you may experience anything from annoying driveability issues to downright dangerous driving conditions. While the symptoms of a bad throttle position sensor can often mimic those of other issues, when taken as a whole they allow for easier diagnosis.
Here’s how to confirm you have an issue with the TPS and how much it’s going to cost to fix.
What Does a Throttle Position Sensor Do?
The throttle position sensor monitors the exact position of your throttle plate (a valve that controls how much air enters your engine). As you step on the gas pedal, the TPS sends precise signals to your car’s Engine Control Module (ECM), which then calculates how much fuel to inject into the engine.
Modern cars use an electronic throttle control system, called “drive-by-wire.” Instead of a mechanical cable connecting your gas pedal to the throttle, sensors and electric motors handle this job. When you push down on the accelerator pedal, the TPS helps the ECM determine exactly how far the throttle should open based on a variety of factors (e.g. vehicle speed, engine load, driving conditions, etc.).
Most newer vehicles use multiple throttle position sensors to act as a fail-safe measure. If one sensor fails or sends incorrect data, the backup sensor helps prevent potential issues. This redundancy is what helps prevent disastrous scenarios in case of malfunction.
See Also: How Drive-By-Wire Throttle Works
Common Signs of a Bad Throttle Position Sensor
1) Check Engine Light
The most reliable indicator of a TPS problem is the check engine light accompanied by specific trouble codes. When your TPS starts failing, it sends incorrect signals to your car’s computer, causing the warning light to come on.
Using a code reader (OBD2 scan tool), you’ll typically see codes P0120 through P0124, which all relate to TPS circuit problems. Even if your car seems to run normally now, don’t ignore this warning. If you don’t have access to a scan tool, check if any local auto parts stores will scan it for you (many of them do it for free).
2) Poor Acceleration Response
When your TPS fails, your car’s computer receives incorrect information about gas pedal position, leading to unpredictable acceleration. You might notice hesitation when pressing the gas, a delay before the car speeds up, or sudden surges in power.
Some drivers explain it as if the car’s holding back or that it takes more pedal pressure than usual to accelerate. This symptom can be especially noticeable when trying to pass other vehicles or merge onto the highway.
In some cases, the vehicle will actually go into “Limp Mode” as a way of preventing any engine damage.
3) Random Engine Stalling
Engine stalling can happen without warning at ANY speed when your TPS malfunctions. Since your car’s computer is getting false information about throttle position, it may cut fuel delivery at the worst possible times.
Best case, your car stalls in your own driveway. Worst case, it stalls while idling at a stoplight of a busy intersection or even driving on the highway. The unpredictability of this can create dangerous driving situations. Some drivers may experience repeated stalling episodes, while others have infrequent, random occurrences.
4) Irregular Idle Speed
A faulty TPS can cause your engine’s idle speed to fluctuate unpredictably. You might notice the RPMs climbing and falling while stopped, or the engine may feel rough and unsteady at idle. This symptom can feel like the car is surging or lurching slightly, even when you’re not touching the gas pedal.
Pay attention to your tachometer; it should be at a constant speed while idling. If it’s moving up and down by itself, it’s very likely that your TPS is sending incorrect signals to the engine computer.
5) Transmission Shifting Problems
Because your transmission relies on accurate throttle position data to determine shift points, a bad TPS can cause erratic shifting. Delayed shifts, harsh shifts, or shifts occurring at the wrong speeds are all a possibility.
The transmission might also get confused about which gear to select, leading to unnecessary gear hunting or refusing to downshift when needed for passing or climbing hills.
If this is the only symptom you’re experiencing, your problem is likely transmission related. But when experienced with a combination of others listed here, the throttle position sensor is a definite possibility.
6) Random Jerking or Bucking
Your vehicle may buck or jerk unexpectedly, especially during steady-speed driving or light acceleration. Unlike transmission-related jerking, TPS-induced bucking can happen even when your car isn’t shifting gears.
The jerking motion often feels like someone is repeatedly tapping your brakes or changing the fuel supply to your engine. This symptom almost always occurs alongside acceleration problems and can vary in intensity from a slight nudge to violent jerking that makes the car difficult to control.
7) Reduced Fuel Economy
While a drop in MPG is common with what seems like most engine issues, it also applies here. When your TPS sends incorrect data, your engine’s fuel management system can’t optimize the air-fuel mixture so it might be sending more fuel than necessary into the combustion chamber.
You might notice a significant drop in fuel efficiency, sometimes as much as 10-20% below normal. Try to keep track of your fuel consumption. If you’re filling up more frequently despite no major change in driving habits, alongside other symptoms on this list, your TPS might be to blame.
8) Engine Misfires
A misfire can be hard to detect but many will describe it as a stumble or momentary loss of power. Some drivers will say that it feels like the engine is “skipping a beat” or temporarily losing power before recovering.
These misfires happen because the incorrect throttle position data leads to improper fuel delivery. You may notice the engine running rough, especially during steady-speed cruising or light acceleration.
Throttle Position Sensor Replacement Cost
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A TPS replacement typically costs between $150 to $400, though prices can vary significantly based on your vehicle’s make and model.
A quality sensor by itself usually runs $50 to $150, while labor costs range from $100 to $250. Luxury and performance vehicles often fall on the higher end of this range, and some models may even exceed it.
Labor costs depend on sensor location and accessibility. Some vehicles allow easy access to the TPS, making replacement a straightforward 1-2 hour job. Others require removing multiple components to reach the sensor, increasing labor time and cost. Your location also affects pricing as locations closer to a city center and dealerships generally charge more than rural shops or independent mechanics.
Since replacing the TPS is fairly easy in most cases (depending on its location), the task is a good candidate for DIY replacement. The job only requires basic hand tools and careful attention to electrical connections. A quick search on YouTube is often all it takes.
However, some very modern vehicles may need computer system recalibration, which requires professional diagnostic equipment.
For most vehicles, independent repair shops offer the best value for TPS replacement. While dealerships may have a nice waiting room with free coffee, they also typically charge premium rates. Most local mechanics can usually perform the same work for less. Just make sure your chosen shop has a good reputation with positive customer reviews.
FAQs
Can You Fix a Bad Throttle Position Sensor?
No, a bad throttle position sensor cannot be repaired. If testing shows the TPS has failed, replacement is your only option. The sensor is a sealed electronic unit that cannot be repaired or rebuilt.
Is It Safe to Drive With a Bad TPS?
No, it isn’t safe. Driving with a failing throttle position sensor is risky and potentially dangerous. When the sensor completely fails, your car’s computer will activate a fail-safe mode (Limp Mode) that limits engine RPMs and speed to protect the engine. While this might let you get to a nearby repair shop, it’s not suitable or safe for regular driving.
If you notice TPS symptoms, have the sensor tested and replaced promptly. Continuing to drive with a failing sensor can lead to unpredictable behavior like sudden stalling or power loss – particularly dangerous in traffic or on highways. While TPS failure is typically a result of normal wear over time, ignoring the symptoms can lead to additional engine and transmission problems.
What Causes a TPS to Fail?
While normal wear from years of driving is common, several specific issues can speed up sensor failure or cause premature problems.
Common causes of TPS failure include:
- Electrical Issues – Corroded connections, damaged wiring harnesses, or short circuits can disrupt sensor signals.
- Physical Contamination – Dirt, carbon buildup, or oil seeping into the sensor housing can interfere with its operation.
- Water Damage – Exposure to moisture (e.g. improper engine bay cleaning) or environmental conditions can short out the sensor.
- Heat Stress – Constant exposure to extreme engine temperatures can degrade internal components over time.
- Mechanical Damage – Vibration and impact from road debris or careless engine bay work can damage the sensor.
- Circuit Board Failure – Internal electronic components can fail due to age or heat cycling. Particularly common with cheap, aftermarket sensors.
- Poor Connections – Loose mounting or improper installation can cause erratic sensor readings.
While you can’t prevent normal wear, regular engine bay cleaning (done correctly) and prompt attention to any engine oil leaks near the sensor can help extend TPS life. Being careful during engine maintenance to avoid disturbing or damaging the sensor and its wiring can also prevent premature failure.
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I have a 2014 Toyota Camry. When driving on the highway and you have the cruise control set at 70. A strong head wind. A slight grade. Will make the car’s transmission down shift to 3rd, some times 2nd gear. The Toyota dealership told me it was normal to maintain speed. When I asked them to check for codes. the service manager got agitated and was adamant that there was nothing wrong with my car and refused to check for codes. Car only started doing this at 120,000 miles. Some days it’s fine and acts normal.
That sounds normal to me. Strong head winds take more power to maintain the same cruising speed. Toyota Camrys don’t have that much power, so they have to downshift to maintain 70.
I have a 2015 chevy silverado – changed the throttle position sensor and now the car wont go forward only reverse.
Hello, I need a little guidance on ruling out possible issues with my 2015 Jeep Wrangler 4×4. Here are the symptoms- Vehicle engine will randomly not turn over, but all lights bells and whistles work fine. no clicking sounds to indicate battery issue but i still replaced battery. Ive replaced crank shaft sensor, not much change. Alternator and starter seem to be fine. (not too sure about the starter though, im still researching to learn) So far the only thing that is working for her to actually turn on is when i put a little forceful shaking to the wire housing closest to battery and towards the wind shield. A few good shakes and rattling and then she turns on and runs perfect. (Does NOT shut off while driving). Jeep will be fine for one or two days or for months, it is very random. I have noticed that this happens more often in the mornings when there is moister still- idk if this may have an effect on whatever the issue may be. i am going to inspect the wiring that i wiggle for wear and tear or damages. I recently changed a damaged oil cooler/filter when she started emptying all the radiator water and coolant and then over heated slightly. Coolant reservoir stayed full. after that fix she turned on , ran, kept fluids in and no check engine light. next morning went to turn and back to no engine turn but all lights work perfect. I’ve taken her to multiple mechanics w/ multi diagnosis charges and none had an answer after other than trying to sell me a battery each time so ive been doing my own research.
Any advice would be much appreciated!
Check your wire harness. You have a corroded wire connection.
could be weak battery or terminales remove and clean with batter post tool cover with anti corosn grease
I have 2000 ford ranger xlt replaced fuel pump it will start if you put fuel in throttle body but will shut off as soon as fuel is used, new fuel pump installed but not getting current to run pump where does it get current to run pump did a bench test and used groung and positive wire pumps works fine
Have you checked the fuel pump relay and any other fuses relating to the fuel system?
My 2014 VW Jetta is having inconsistent rough idling, bucking at low speeds, and hesitating every now and then at moderate high way speeds. I have had the injectors, spark plugs, pcv valve repalced and have had it walnut blasted to no avail.
It isn’t constant but it occurs relatively often. Do you think this could be the issue?
I don’t know, you’ll need to have that problem professionally diagnosed.
my coworker i dont know what it is i just wanna get it fixed
i have 02 suburban it starts hesitating around 40 to 50 mph can someone tell what it is
Are there any other symptoms associated with the hesitation?
nope just that I have been told it was my fuel pump going bad
That may cause those symptoms. Who told you that?
nope i changed the tps it still does the same thing
1992 chevy v8 5.0 runs extemly rough at start . Hard to keep running but after sometime it will smooth out and run very smooth. Any ideas ? Replaced sensor at back of distributor and one on side of carb. Only thing not changed is the TPS.
Just bought a 94 cavalier in fairly good condition. For about two months it ran well, but then the engine light began to come on and after that, it began to be very difficult to start. I would turn the key to start but when I let go, the car engine died, never turning over.
After I had both the fuel injector and the ignition coils replaced, it would start. But after two days it started rough, if at all, the engine only coming on if I held the ignition for half a minute or so without stepping on the gas. So I replaced the fuel filter and now it starts without having to hold the ignition for a prolonged amount of time, yet the engine starts off very rough, off time, for about one to two minutes, until the idle finally settles. I did purchase an idle control sensor (the car vibrates a lot in idle) but I’m beginning to wonder if I also need to change the TPS as well.
I think it’s unlikely to be the TPS. What codes were stored with your check engine lights?
How do you determine if it is necessary to replace the entire throttle body vs. the PCV (valve) or TPS (sensor)?
If the check engine codes are P0731 (trans), P0638 (throttle actuator) and P0420 (catalytic converter) might they be related?
The car is a 2004 Outback (2.5L) that had the gas peddle assembly replaced less than six months ago. When it began behaving the same — could no longer accelerate past ~15mph — we figured it was the peddle again. (Transmission was also said to be in good shape around that same time when checked at an AAMCO.) The car has ~175K. What might cause it to fail — or is it possible that replacing the TPS and PCV would be sufficient?
PCV valves are cheap and easy to replace. There are a couple tests you can look up to know if your PCV valve is bad.
The throttle body is a mechanical component on the 2000 to 2003 Outbacks. I’m not sure if 2004 switched to electronic throttle control (i.e. drive by wire). If you have throttle cables like the 00-03 Outbacks did, check to make sure the throttle cables are adjusted properly.
You may be able to physically inspect the throttle body assembly and cables to see if they are bad. Test the butterfly valve to make sure it opens and closes smoothly. The throttle body sits on top of the engine in the back and is easy to get to. You’ll probably want to replace the throttle body gasket while you’re in there.
Thank you. This is very helpful, Sean. In answer to your question, think the 2004 is a drive-by-wire throttle (AT, 2.5L base model). What purpose does the throttle body gasket serve?
This car has had a series of acceleration problems for which I’d appreciate your feedback:
The first acceleration issue occurred in 2016 after the car abruptly failed to respond to the accelerator peddle while attempting to move forward after a stop light (dealer replaced peddle assembly). In October 2020 after the car lost acceleration and wouldn’t go past ~10mph (P21378), the peddle assembly was again replaced, this time by an independent shop. When the same symptoms appeared in February, I assumed the replacement peddle assembly was to blame — but the shop now wants ~$1500 to replace the throttle body (reason why I found your blog).
January 2020 was the first time the car had an acceleration problem since the initial replacement of the accelerator peddle assembly in 2016. Last year at this time, the problem consisted of over-revving the engine when attempting to reach ~25mph (car threw a P1091 and had no power going up hills).
A year ago this month, a Subaru dealer tried, unsuccessfully, to replace a “motor AY assembly” aka “tumble generator valve”. When they went to install the part the first time, they broke it. After obtaining a new one, they installed it but the code didn’t clear so they reinstalled the original and called with a recommendation to clean the intake manifold. (It didn’t make sense that the intake manifold would require cleaning since the head gaskets had been replaced in 2019, at which time the manifold presumably would have been inspected/cleaned.) In any case, the dealer wasn’t confident that cleaning the intake manifold would clear the code so they refused to guarantee the work (quoted $1K to do the job). As a second opinion, the car was towed from the dealer to an independent repair shop who replaced the intake manifold gasket — after reporting that the tumble generator valve was physically obstructed by improper alternator installation (a mobile mechanic had replaced the alternator shortly before the P1091 code had appeared).
The car ran without issue from April last year until October when the accelerator peddle was replaced. It then ran OK from October until February, when the acceleration problem reappeared (P0731, P0638). With this in mind, some follow-up questions:
When you mention checking to see if the butterfly valve is opening and closing smoothly, are you referring to the same butterfly valve the dealer replaced but then yanked?
How closely positioned is the intake manifold and the throttle body?
Is it possible that the dealer, the independent shop that discovered the obstructed linkage or even the shop that did the head gasket work in 2019 damaged or improperly reinstalled these parts, leading to the current situation?
Lastly, are these acceleration issues in any way related to one another? In other words, might there be a common cause running through this and, if so, what else should be inspected or replaced?
The throttle body gasket keeps ambient air separate from air that has entered the intake through the air filter.
Hmm, I could definitely see the TGV assembly causing the issues you’re experiencing if the TGVs were stuck closed. I was referring to the butterfly valve on the throttle body, not the TGVs the dealership was referring to.
Here’s a great video that will show you what the TGVs look like. It’s geared toward a more performance oriented audience and shows the TGVs from a WRX, but you’ll get the idea of how they work. The TGVs sit between the intake manifold and the cylinder heads. At 2:23, he talks about the implications of pulling the TGV position sensors off without aligning them properly. I have a service manual on a 2004 Subaru Impreza handy (didn’t have one for an 04 Outback) and that manual specifically says not to remove the TGV position sensor, “since it cannot be adjusted during installation”. https://www.youtube.com/watch?v=3v54m161yXI
The throttle body is mated to the back of the intake manifold. Take a look at this video around 1:55 and you’ll see where it is and what it looks like: https://www.youtube.com/watch?v=H-YfyXyPvrE
It is possible that something was improperly repaired, causing the acceleration issues. I’m not sure. Unfortunately it’s really hard to say definitively what’s going on without some further testing. If it were my car, I would have to take the TGVs and throttle body off, inspect them, test sensors, etc. until I could start narrowing down the problem.
I have a 94 Silverado with a 5.0 & a automatic. It wants to idle low and die in gear at a stop light. New plugs, wires, vacuum lines, Idle Air Control valve. I cleaned the throttle body. Tons of power. Idles at around 400 rpm.
Throttle position sensor ?
Have you checked the ignition timing and tested for vacuum leaks?
maybe a M.A.P. sensor ? its called a manifold absolute pressure sensor M.A.P.
Can anyone please, tell me why my car jerks
throttle position sensor is bad,or there is a vaccume leak have it checked out before you buy the sensor,or maybe it needs adjustment if there aint no adjustment get a new one.
replaced throttle position sensor,and idle control valve on a 454 vortect,, cranks easy, runs but idles down low rpms and dies,, give it gas .it takes gas but backfires.. im lost,,
Did you test for vacuum leaks?
Clean the throttle body with carb cleaner
I have a 99 ford ranger. wont go beyond 75 mph.
Is the engine struggling? Any vibration as you approach 75 mph? You’ll probably have to take it to a shop to have them help you diagnose the problem.
Speed limit is 65 . Consider it fixed speed racer
Its in texas…speed limit is 90.
Who do my car jerk when it want to change gear
Is the car an automatic? If so, the transmission fluid may need to be changed.
I have a 2004 trailblazer that has rpm surge in drive but runs fine in 3rd I had coil packs go bad so I replaced them. No check engine light and no codes could it be a bad throttle sensor
I suppose it could be, but I doubt it. Have the spark plugs also been replaced recently?
I have a mystery I need help. Driving my 97 Oldsmobile cutlass supreme 3100 engine drove perfectly. Goin down the highway all of a sudden it does a lil jerk I loose all power to the accelerator won’t rev up and it dies pull over won’t start next day it fired right up. So I replaced the crank sensor drove perfect for a day then going down the highway same thing died won’t start. Replaced the ignition module drove perfectly for a day then same thing won’t start. I’m lost and out of ideas can anyone please help. The fuel pump is work I have spark the fuel filter brand new. I’m out of ideas. Could it be the coil packs or the throttle position sensor? Goes straight from running fine no loss of power no jerk no nothing to dead.
I would test the coil pack next.
I had a 96 tahoe that did the same thing. Turned out to be a worn distributor. Replaced the distributor and didn’t have any more trouble.
I just replaced my TPS & now all the symptoms are WORSE! Now when I take off it goes from 1st all the way to Overdrive almost immediately & when I floor it it won’t kick down to lower gear? I assume There is an adjustment I need to make. 1997 Infiniti QX4
I’m not sure if there’s an adjustment required. Check the specifications of the factory service manual to know for sure.
What was the reason for replacing the TPS? Perhaps it wasn’t the root cause of the issue.
great post ——-solved my problem thanks
Yes but does my 2001 dodge Durango stall because of the security system maybe?