P0122 – Meaning, Causes, Symptoms, & Fixes

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.

 P0122 Symptoms

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

 P0122 Causes

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

Code P0122 Severity- High

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

  • 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.
    1. 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.
    1. 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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