The P0668 OBD-II code indicates a problem with the internal temperature sensor circuit of the Powertrain Control Module (PCM), Engine Control Module (ECM), or Transmission Control Module (TCM). This code is triggered when the temperature sensor reports a low voltage, suggesting that the module may not be able to accurately monitor its temperature, which is crucial for its operation.
What Does the P0668 Code Mean?
The P0668 code means that the PCM/ECM/TCM has detected a low voltage from its internal temperature sensor. This sensor is vital for preventing the module from overheating and ensuring it operates within the optimal temperature range. When the sensor fails to report correctly, the vehicle’s performance may be compromised.
What Causes the P0668 Code?
- Failure of the Powertrain Control Module (PCM)
- Failure of the Transmission Control Module (TCM)
- Wiring issues such as shorts or disconnections in the sensor circuit
What Are the Symptoms of the P0668 Code?
- Transmission may not shift properly
- Decreased engine performance
- Increased engine temperature
How Serious Is the P0668 Code?
The P0668 code is classified as urgent, meaning immediate action is necessary. Ignoring this code could lead to severe damage to the vehicle’s control modules, resulting in costly repairs and potential safety hazards for the driver and passengers.
How to Diagnose the P0668 Code
- Use an OBD-II scanner to confirm the P0668 code and check for any other related codes.
- Inspect the wiring and connectors associated with the PCM, ECM, and TCM for any visible damage or corrosion.
- Test the internal temperature sensor’s functionality to ensure it is reporting the correct values.
- Check for proper grounding and voltage supply to the control module.
Common Repairs for the P0668 Code
- Repair or replace damaged wiring or connectors
- Replace the faulty Powertrain Control Module (PCM)
- Replace the faulty Transmission Control Module (TCM)
- Clear the trouble codes and perform a test drive to see if the issue reoccurs
How Much Does It Cost to Fix the P0668 Code?
The cost to fix the P0668 code can vary widely depending on the root cause of the issue. Simple wiring repairs may cost around $100 to $300, while replacing a PCM or TCM could range from $500 to $1,500 or more, depending on the make and model of the vehicle.
Can I Fix the P0668 Code Myself?
While some diagnostic steps can be performed at home, such as inspecting wiring and connectors, repairing or replacing control modules typically requires specialized knowledge and equipment. If you are not experienced in automotive repairs, it is advisable to seek professional assistance to ensure the issue is resolved correctly.
