PCM/ECM/TCM Internal Temperature Sensor Range/Performance
The P0667 code indicates that the powertrain control module (PCM), engine control module (ECM), or transmission control module (TCM) has detected an internal temperature sensor reading that is out of the expected range or not performing correctly. This sensor monitors the temperature inside the module to prevent overheating. A fault can cause the module to miscalculate engine or transmission parameters, potentially leading to drivability issues.
1. Most Common Causes
- Internal failure of the temperature sensor integrated into the PCM/ECM/TCM
- Internal hardware failure of the control module (processor or signal conditioning circuit)
- Calibration error or software corruption in the control module
- Physical damage to the control module due to overvoltage, water ingress, or excessive vibration
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine performance issues such as stalling, hesitation, or rough idle
- Transmission shifting problems (if TCM involved)
- Reduced fuel economy
3. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for other related codes.
Step 2: Inspect the PCM/ECM/TCM connectors and wiring for damage, corrosion, or loose connections.
Step 3: Monitor the module's internal temperature using a scan tool to see if it's within normal range.
Step 4: If wiring and connectors are fine, the module may need to be replaced or reprogrammed.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with this code as it can lead to engine or transmission performance issues and potential damage. Have it diagnosed promptly.
How much does it cost to fix?▼
Diagnosis typically costs $50-$150. If the module needs replacement, costs can range from $500 to $1500 including labor and programming.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.