Our emissions expert has put together the following information about the P0123 code. We have also included diagnostic procedures you can take to your repair shop if the mechanic is having difficulty analyzing the P0123 code.
Fault P0123Code Definition:
P0123 Code is triggered when the voltage output from the Throttle/Pedal Position Sensor/Switch to the PCM is too high.
The Throttle Position Sensor/Switch is located on the Throttle Body of the Intake Manifold and the Pedal Position Sensor/Switch is located on the Accelerator Pedal. These sensors provide precise input from the driver’s foot in terms of how much power is needed—and how urgently—from the engine.
As the Throttle Position Sensor is rotated from its base resting position to full acceleration, it sends a increasing voltage signal to the Powertrain Control Module (PCM). This decreasing or increasing voltage signal is used by the PCM to manage the Air Fuel Ratio and Spark Timing of the engine as well as other emissions system components.
Symptoms:
- Check Engine Light will illuminate
- In many cases, no abnormal symptoms may be noticed
- In some cases, the engine may be hard starting
- In some cases, the engine may hesitate during acceleration
Possible Causes:
- Defective Throttle or Pedal Position Sensor or Switch
- Dirty or carbon-filled Throttle Body
- Torn or jammed floor mats
- Chafed or corroded Throttle/Pedal Position Sensor, wiring, or connections
Possible Misdiagnoses：
- Throttle or Pedal Position Sensor is replaced when the real problem is a poor connection or chafed wiring
- Throttle Position Sensor/Switch is replaced when the real problem is a dirty or carbon-filled Throttle Body
- Pedal Position Sensor is replaced when the real problem is torn or damaged floor mats