Air & Fuel Mixture ControlOBD2 Codes

P0122 – Meaning, Causes, Symptoms, & Fixes

Reading Time: 2 minutes


Code P0122 Definition

Throttle Pedal Position Sensor/Switch (TPS) A Circuit Low Input

What Does Code P0122 Mean?

Code P0122 is triggered when your vehicle’s Engine Control Module (ECM) detects that your Throttle Position Sensor (TPS) circuit A is reporting an output voltage that is below its expected voltage. Depending on your vehicle, your TPS lower output voltage limit should be around .17 to .20 volts, and if the ECM detects that it has dipped below that, then it will trigger Code P0122.

 What Are the Symptoms of Code P0122?

  • Check Engine Light
  • High Idle
  • Possible Stalling or Surging
  • Hesitation upon acceleration

 What Causes Code P0122?

  • TPS Mounted Incorrectly
  • Faulty or Frayed TPS Wiring
  • TPS Circuit Short to Ground
  • Faulty TPS

How Serious Is Code P0122? -Severe

When P0122 is triggered, your ECM will be instructed to go into failsafe mode. When this happens, your vehicle will have substantial trouble with acceleration, exhibit limited speeds, and possibly even stall. We recommend that you confront this issue as soon as possible.

Code P0122 Common Diagnosis Mistakes:

A common diagnosis mistake made when dealing with Code P0122 is replacing the TPS before visually inspecting the wiring or connectors. Often times frayed or damaged wiring is the issue, and replacing the TPS isn’t actually necessary.

P0122 Diagnosis and Repair:

  • Tools Needed to Diagnose:

Difficulty of Diagnosis and Repair

  1. Check to see if there are any other codes along with P0316 and clear your Check Engine Light with FIXD.
  2. Check the freeze frame data in order to pinpoint the issue.
  3. Conduct a visual inspection of wiring around the TPS for possible wire fraying or disconnection. If any wiring issues are found, you must repair them, clear your codes with FIXD, and re-scan to see if P0122 still shows up.
  4. Make sure the TPS is mounted correctly. If it is not in the correct position, it can give out inaccurate voltage levels. Adjust TPS if you think it is out of position
  5. If after all of these steps Code P0122 is still present, you may need to replace your TPS.


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  1. I cleaned the throttle body and position sensor . Checked spark plugs and wires , cleaned and replaced air filter. No more codes and engine running smooth.

    1. How and what did you clean the position sensor with

  2. had BATTERY CHECKED not good.put NEW battery.

  3. I am still having trouble with idle, it is high and it varies. Just before this code came up I was and am having a problem with high coolant temperature so I looked around at and moved some of the wires near the thermostat. Some of those wires go to the TPS. I might have a wiring problem of some kind….and I also still have a problem with my coolant gauge reading way too high but that does not seem to turn on any lights…I don’t know what’s up.

  4. Toyota Ractis 2006 model. After changing the gearbox (transmission), often times the car just goes into limp mode. In the morning when you start it, its normal with normal raves. But after driving it for few kms, limp mode comes back. What should I do?

  5. My Chev Spak, is shaking at idle and hasitating when eccelarating it sometimes shows up the engine light.

  6. After replacing dead battery in a 2013 VW jetta SE 2.5l L5 with 155k miles, ECP and Check engine light came on. The car shifted roughly and transmission released with a clunk at stops. Codes PO122 and PO638. Erased the codes with FIXD and drove again, and the same codes came up. Drove a couple more times then looked up codes. One site said check wires to the accelerator pedal. They seemed tight. I operated the accelerator through its full range with engine off, started the car again and no lights, car drove like normal. Besides a few electrical quirks, this has been a great car.

  7. I replaced my tps sensor and it’s still acting the same. The plug that goes to it looked fine. Any suggestions on what to do now?

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