What it means
The internal temperature sensor of the control module shows intermittent jumps or dropouts. Module thermal protection may falsely activate or fail to activate when needed.
At a glance
- Usually lights the check-engine light
How it works
Control Module Internal Temperature Sensor A monitors temperature inside the module so the controller can respond to heat. This code sets when the sensor's signal becomes intermittent or erratic, which can make the module's thermal protection respond incorrectly.
Common causes
Most likely first.
- Cracked solder joint at internal sensor
- Electromagnetic interference on sensor trace
- Connector with intermittent contact under vibration
Symptoms
- Check-engine light
- Intermittent warning or reduced engine performance
How to diagnose it
- Record freeze-frame data and monitor the module temperature reading on a scan tool for implausible jumps or dropouts.
- Check for related module or communication codes and note whether the fault appears during vibration, heat, or a particular operating condition.
- Inspect the module connector and accessible wiring for loose terminals, corrosion, or signs of vibration-related movement.
- Check the module's power and ground connections for intermittent contact while observing the temperature reading, using the manufacturer's wiring information.
- If external connections are sound, have the module's internal sensor circuit assessed using the manufacturer's diagnostic procedure.
Common fixes
- Repair loose, corroded, or intermittent module connector contacts.
- Repair any damaged power, ground, or wiring connections that affect the module reading.
- Replace or repair the control module if its internal sensor or solder joint is confirmed faulty.
Can I keep driving?
Use caution and limit driving if warnings or reduced performance occur, since the module may misjudge its temperature and affect engine control. Stop if the vehicle behaves unpredictably or enters a severe power limitation.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.