Internal malfunction detected in auxiliary automatic transmission fluid pump control module
What it means
The control module for the auxiliary automatic transmission fluid pump has detected a fault inside itself. The pump keeps fluid moving when the engine is off, such as during auto stop-start.
Can I keep driving? Usually yes in the short term, but the car may shift poorly or refuse to auto stop; get it read soon.
What this part does
This module runs the auxiliary electric transmission fluid pump, controlling its speed and monitoring its operation. It takes requests from the transmission control module and drives the pump when the engine is not providing fluid pressure, such as during start-stop operation. Some designs use high voltage, where service is for trained people. A failure can lead to delayed engagement or shifting problems.
Common symptoms
What you'll notice
- Check-engine or transmission warning light on
- Rough or delayed shifting after auto stop
- Auto stop-start disabled
Common causes
Most likely first
- Poor power or ground at the pump control module
- Corroded connector
- Internal control module fault
- Pump fault
How to diagnose & fix
Work through it in order
- Read all transmission codes.
- Check the pump fuse and low-voltage battery.
- Inspect the pump module connector and ground.
- Check power and ground at the module.
- Replace the module only after these pass.
Related codes
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