P1122 Throttle Position (TP) Sensor Circuit Intermittent Low Voltage

Definition

Common causes

• Faulty throttle position sensor (TPS)
• Poor electrical connections or wiring issues
• Corroded or damaged connectors
• Faulty engine control module (ECM)
• Grounding issues
• Intermittent short circuits
• Voltage supply problems
• Mechanical binding in the throttle body

Common misdiagnoses

• Faulty throttle position sensor
• Wiring issues or damaged connectors
• Faulty engine control module (ECM)
• Vacuum leaks
• Faulty accelerator pedal position sensor
• Issues with the intake air temperature sensor
• Problems with the mass airflow sensor (MAF)
• Fuel delivery issues
• Ignition system problems
• Other sensor malfunctions (e.g., coolant temperature sensor)

Troubleshooting steps

1. 1. Visual Inspection

   Wiring and Connectors: Check the wiring and connectors associated with the throttle position sensor for any signs of damage, corrosion, or loose connections

2. 2. Sensor Condition

   Inspect the throttle position sensor itself for physical damage or contamination

3. 3. Check the Throttle Position Sensor

   Resistance Testing: Use a multimeter to measure the resistance of the TP sensor. Compare the readings to the specifications provided in the vehicle’s service manual

4. 4. Voltage Testing

   With the ignition on (engine off), check the voltage at the TP sensor connector. You should see a reference voltage (usually around 5 volts) and a varying voltage as the throttle is moved

5. 5. Inspect the Throttle Body

   Clean the Throttle Body: Carbon buildup can affect the throttle position sensor's readings. Clean the throttle body and ensure the throttle plate moves freely

6. 6. Check for Mechanical Issues

   Ensure that the throttle plate is not sticking and that the throttle linkage is functioning properly

7. 7. Check for Ground Issues

   Ground Connections: Ensure that the ground connections for the TP sensor and the engine control module (ECM) are secure and free of corrosion

8. 8. Scan for Additional Codes

   Check for Related Codes: Use an OBD-II scanner to check for any other trouble codes that may be present. This can provide additional context for the issue

9. 9. Test the Engine Control Module (ECM)

   ECM Functionality: If all other components check out, the issue may lie with the ECM itself. Ensure that the ECM is functioning properly and that it is receiving the correct signals from the TP sensor

10. 10. Perform a Wiggle Test

    Intermittent Issues: While monitoring the TP sensor voltage with a multimeter, gently wiggle the wiring harness and connectors to see if the voltage fluctuates. This can help identify intermittent wiring issues

11. 11. Replace the Throttle Position Sensor

    If all tests indicate that the sensor is faulty, replacing the throttle position sensor may be necessary

12. 12. Clear Codes and Test Drive

    After repairs, clear the trouble codes using an OBD-II scanner and take the vehicle for a test drive to see if the code returns

13. 13. Consult a Professional

    If the issue persists after following these steps, it may be best to consult a professional mechanic for further diagnosis.Additional Tips: - Always refer to the vehicle’s service manual for specific testing procedures and specifications. - Ensure that you have the proper tools and safety equipment when performing any diagnostics or repairs. By following these steps, you should be able to identify and resolve the issue related to the P1122 code