Error Code P1222 is defined as Throttle Motor Circuit Problem. This means loss of power for the engine, causing the vehicle to run slower than it should be.

This error code is a generic trouble code, meaning it applies to all vehicles equipped with OBD-II system, or vehicles made since 1996 up to present. Specifications on the definition, troubleshooting, and repairs of course, vary from one make and/or model to another.

Definition

The vehicle’s throttle control motor is controlled by the PCM or powertrain control module (also referred as ECM or engine control module, or ECU or engine control unit in other vehicle makes). It opens and closes the throttle valve. The diesel throttle position, which is mounted on the throttle body, detects the fully open condition of the throttle body. When the Error Code P1222 is stored, the PCM shuts down the power of the throttle control motor.

Common Symptoms

Symptoms for this error code usually starts with the activation of the Check Engine light. For drivability, the vehicle suffers from slow acceleration from time to time.

Possible Causes

There are many factors that may result to this error code, but usually, the problem arises from:

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  • Faulty throttle motor
  • Open or shorted throttle motor harness
  • Wiring fault or poor electrical connection in throttle motor circuit
  • Faulty throttle valve
  • Faulty throttle drive gear
  • Failure of throttle body sensor
  • Vacuum leak
  • Faulty spark plug
  • PCM fault (rare)

How to Check

Check for open or short condition in throttle control motor circuit

Check for open or short in diesel throttle position switch circuit

Check throttle valve, throttle drive gear, and throttle control motor

Check diesel throttle body, and diesel throttle position switch

Check the PCM

How to Fix

Repairs for this error code of course, depend from the diagnosis. Some of the most common repairs include:

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  • Repair or replacement of throttle control motor circuit
  • Repair or replacement of diesel throttle position switch circuit
  • Repair or replacement of valve, throttle drive gear, and throttle control motor
  • Repair or replacement of diesel throttle body, and diesel throttle position switch
  • Replace and/or update PCM

Once again, the specifics of the definition for this error code vary from one make and/or model to another. Thus, if you’re using a generic code reader, you may get a different, potentially wrong description of the error code. It is best to take your vehicle to your dealer to get the appropriate and specific reading from their advanced code reader. It’s the safest way to move forward.