PCM/ECM/TCM Internal Temperature Sensor Circuit High
The P0669 code indicates that the Powertrain Control Module (PCM), Engine Control Module (ECM), or Transmission Control Module (TCM) has detected an abnormally high voltage signal from its internal temperature sensor circuit. This sensor monitors the module's internal temperature to prevent overheating. A high circuit condition typically means the sensor is reading an excessively high temperature or there is a short to voltage, which can lead to incorrect temperature readings and potential module damage.
1. Most Common Causes
- Internal failure of the control module temperature sensor
- Damage to the PCM/ECM/TCM printed circuit board (PCB)
- Loose or corroded connections at the module connector
- Previous module overheating that damaged internal components
- Complete control module failure
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine performance issues (hesitation, stalling)
- Transmission shifting problems
- Overheating of the control module
3. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for other related codes.
Step 2: Visually inspect the PCM/ECM/TCM connectors and wiring for damage, corrosion, or loose connections.
Step 3: Test the internal temperature sensor circuit using a multimeter to check for high voltage or shorts.
Step 4: If no wiring issues are found, 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 module overheating and potential failure, causing stalling or transmission issues.
How much does it cost to fix?▼
Diagnosis typically costs $50-$150. If the module needs replacement, it can range from $500 to $1500 including labor.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.