P0669 code meaning
Control Module Internal Temperature Sensor A Circuit High
Powertrain system Generic code P06xx codes Check engine light
What P0669 means
Control modules measure their own circuit board temperature with an internal sensor to protect output stages (overtemperature is P0634) and, in GM transmission modules, as a substitute for fluid temperature. In GM's 6T70/6T75 and related automatics the sensor sits in the transmission module inside the valve body, with no external wiring – so the repair is practically always the module or valve body assembly. P0669 means the sensor signal is at the high voltage end (internal open or short to voltage): GM treats a converted value of 249 °C or more for 60 s as a fault, with the lamp after two trips and the power-up temperature as substitute. Unlike P0634, which reports a plausibly high real temperature (GM: 142 °C), P0669 reports a physically impossible value.
P0669 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor2 to 5 hours
- Clears after repairAfter a drive cycle
Symptoms of P0669
- Warning lamp
- Changed shift quality (substitute value)
- Scan tool shows an implausibly high module temperature
Common causes of P0669
- Most likelyModule faulty internally (sensor open)
- PossibleMoisture or corrosion in the electronics
- Less likelyModule supply or software
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Transmission control moduleControl module internal temperature sensor
What each part of P0669 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 6 | Area: computer (engine control module) and output circuits. |
| 69 | The exact fault in that area. |
What to do next
- Note P0669 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0669
What does P0669 mean?
P0669 means "Control Module Internal Temperature Sensor A Circuit High". Control modules measure their own circuit board temperature with an internal sensor to protect output stages (overtemperature is P0634) and, in GM transmission modules, as a substitute for fluid temperature. It is a generic code, so it means the same on every make.
Is it safe to drive with P0669?
Drive gently and only to a workshop. With P0669 the car can go into limp mode (reduced power) to protect itself.
Will P0669 fail an emissions test?
Yes, it can. P0669 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0669 to fix?
Difficulty: hard. A typical repair takes 2 to 5 hours of work. This is a job for a workshop.
Will P0669 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.