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OBD2.help›Powertrain›P0122

P0122

Throttle Position Sensor A Circuit Low Input

The engine computer is receiving a lower-than-normal signal from the throttle position sensor or pedal position sensor. This can cause poor throttle response, rough running, and warning lights. The problem is often a bad sensor, wiring issue, or connector problem.

SEV
3/5
DRIVE
CAUTION
DIY
$20–$150
SHOP
$150–$500

Quick answer

AI-CITATION READY

What it means

P0122 means the ECM/PCM detected a low voltage signal on throttle position sensor circuit A, or on some vehicles the accelerator pedal position sensor circuit. The signal is below the expected range, so the computer cannot accurately determine throttle demand. This can trigger reduced power mode, unstable idle, or other drivability problems.

Can you drive with it?

With caution. You may be able to drive short distances, but acceleration may be poor or unpredictable. If the engine enters limp mode, stalls, or reacts badly to throttle input, stop driving and repair it promptly.

Most common causes

  • Faulty throttle position sensor or accelerator pedal position sensor
  • Damaged wiring, loose connector, or poor terminal contact in the sensor circuit
  • Throttle body contamination or throttle plate binding affecting sensor readings

Typical repair cost

DIY usually runs $20–$150. Typical shop repair lands around $150–$500, depending on the root cause.

01 / Definition

P0122 means the ECM/PCM detected a low voltage signal on throttle position sensor circuit A, or on some vehicles the accelerator pedal position sensor circuit. The signal is below the expected range, so the computer cannot accurately determine throttle demand. This can trigger reduced power mode, unstable idle, or other drivability problems.

02 / Drive status

With caution. You may be able to drive short distances, but acceleration may be poor or unpredictable. If the engine enters limp mode, stalls, or reacts badly to throttle input, stop driving and repair it promptly.

03 / Symptoms

  • Check engine light
  • Poor acceleration
  • Delayed throttle response
  • Limp mode or reduced engine power
  • Rough idle
  • Stalling
  • Hesitation when pressing the accelerator
  • High or unstable idle

04 / Causes

1Faulty throttle position sensor or accelerator pedal position sensorhigh
2Damaged wiring, loose connector, or poor terminal contact in the sensor circuithigh
3Throttle body contamination or throttle plate binding affecting sensor readingsmedium
4Blown fuse, damaged power supply, or poor sensor reference voltagemedium
5PCM/ECM issue or software problemlow

05 / Diagnostic sequence

  1. 01Scan for all stored and pending codes and note freeze-frame data.
  2. 02Inspect the throttle body, throttle sensor, pedal sensor, and wiring harness for damage, corrosion, or loose connections.
  3. 03Check the sensor connector for bent pins, water intrusion, oil contamination, or broken locking tabs.
  4. 04Verify reference voltage, ground, and signal voltage with a multimeter or scan tool live data.
  5. 05Move the wiring harness while watching live data to find an intermittent open or short.
  6. 06If equipped, compare throttle position and accelerator pedal position readings to factory specifications.
  7. 07Clean the throttle body if carbon buildup is causing binding, then recheck operation.
  8. 08Replace the faulty sensor, repair wiring, or address power and ground faults as needed.
  9. 09Clear codes and perform a road test to confirm the repair.

06 / Repairs

1Clean and inspect the throttle body and sensor connector$10–$40
2Repair damaged wiring, terminals, or connector issues$20–$150
3Replace the throttle position sensor or accelerator pedal position sensor if out of range$30–$200
4Replace or reprogram the throttle body assembly if required by the vehicle design$150–$600

07 / Related codes

  • P0120
  • P0121
  • P0123
  • P0220
  • P0222
  • P0223
  • P2135

08 / FAQ

Is P0122 caused by the throttle body or the pedal sensor?

It can be either, depending on the vehicle. Some cars use a throttle position sensor on the throttle body, while others rely on the accelerator pedal position sensor and related throttle control sensors.

Can a dirty throttle body cause P0122?

Yes, if carbon buildup makes the throttle plate stick or prevents normal movement. It is more common to see this code from a sensor or wiring fault, but contamination can contribute.

Will P0122 clear itself?

Sometimes the light may go off temporarily if the fault is intermittent, but the problem usually returns until the underlying issue is fixed.

Do I need to replace the throttle body for P0122?

Not always. The sensor, connector, wiring, or power and ground circuits should be checked first before replacing the throttle body.

09 / Source and method

DATA BASIS
OBD-II REFERENCE + OBD2.HELP
METHOD
STATIC VALIDATION
SAFETY
INFORMATIONAL

This page combines OBD-II diagnostic reference data with OBD2.help generated diagnostic guidance for code meaning, likely causes, and repair direction.

Publishing uses deterministic schema and build validation, plus manual spot checks on representative pages before release.

Safety-critical diagnosis and repairs should be confirmed with a qualified mechanic, especially when the vehicle is misfiring, overheating, or losing power.