P0122 - Throttle/Pedal Position Sensor/Switch A Circuit Low Input

Understanding the Meaning of P0122

The P0122 error code indicates that there is an issue with the Throttle/Pedal Position Sensor/Switch A Circuit. The sensor measures the position of the throttle or accelerator pedal and sends a voltage signal to the engine control module (ECM). When the voltage signal is lower than expected, it triggers the P0122 code.

Common Causes of P0122

There are several reasons that could cause the P0122 error code, including:

• Faulty throttle position sensor
• Malfunctioning accelerator pedal position sensor
• Wiring or electrical connector issues
• Problems with the engine control module (ECM)

Steps to Diagnose and Fix P0122

Follow these steps to diagnose and fix the P0122 error code:

1. Scan for Error Codes

Use an OBD-II scanner to retrieve any stored error codes. If there are other related codes, address them before tackling the P0122 code.

2. Inspect the Throttle Position Sensor

Locate the throttle position sensor and check for visible damage or wear. If it appears damaged, replace the sensor.

3. Check the Accelerator Pedal Position Sensor

Inspect the accelerator pedal position sensor for any signs of wear or damage. If the sensor is faulty, replace it.

4. Examine Wiring and Electrical Connectors

Check the wiring and electrical connectors leading to the throttle position sensor and accelerator pedal position sensor. Look for signs of damage, corrosion, or loose connections. Repair or replace any damaged components.

5. Test the Throttle Position Sensor

Using a digital multimeter, test the throttle position sensor's voltage output while slowly opening the throttle. The voltage should increase smoothly. If the voltage reading is erratic or doesn't change, replace the sensor.

6. Test the Accelerator Pedal Position Sensor

Use a digital multimeter to test the accelerator pedal position sensor's voltage output while slowly depressing the pedal. The voltage should increase smoothly. If the voltage reading is erratic or doesn't change, replace the sensor.

7. Check the Engine Control Module

If all other steps have been completed and the issue persists, the engine control module (ECM) may be at fault. Consult a professional mechanic for further diagnosis and potential ECM replacement.

8. Clear the Error Code

After fixing the issue, use the OBD-II scanner to clear the P0122 error code. If the code returns, repeat the diagnostic process to identify any missed issues.