P0669
Control Module Internal Temperature Sensor A Circuit High
Control module (internal)
Generic OBD-II
High
What it means
P0669 means the temperature sensor built into the engine or transmission control module is reading higher than expected. The module uses this to protect itself from overheating, so it may reduce power or limit functions. It usually points to the module's own power, grounds, or internal circuitry rather than the engine.
High
Can I keep driving? Usually drivable, but the module may cut power or limit functions to protect itself if it thinks it is overheating — have it checked promptly.
Common symptoms
What you'll notice
- Check-engine light on
- Reduced power or a protective 'limp' mode in some vehicles
- Often no obvious driving symptom — the code is stored on a self-check
- Possible related power/ground fault codes stored at the same time
Common causes
Most likely first
- Faulty temperature sensor inside the ECM/PCM/TCM module itselfLikely
- Poor power supply or ground to the control moduleCommon
- Corroded or loose main module connectorCommon
- Excess heat reaching the module (nearby cooling or heat-shield issue)Less often
- Internal control-module failureLess often
How to diagnose & fix
Work through it in order
- Scan for all stored codes and note any power, ground, or related module faults.
- Check the module's power feeds, grounds, and main connector for corrosion or looseness.
- Confirm the module isn't exposed to abnormal heat (missing shield, nearby cooling fault).
- Check for a software/calibration update from the manufacturer.
- If the sensor reads high with good power and grounds, the module is internal-faulted and is replaced/reprogrammed as a last resort.
FAQ
Quick answers
Is it safe to drive with P0669?+
Short trips are usually fine, but the module may limit power to protect itself. Because it points to the computer's own thermal reading, have it diagnosed soon.
Can I just clear P0669?+
You can clear it, but it will return if the internal sensor or the module's power/ground path is still at fault. Fix the cause first.
Related codes
Often seen with P0669
Read & clear P0669 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX