Electric/Auxiliary Transmission Fluid Pump A Control Circuit / Open
The controller cannot drive the first auxiliary transmission fluid pump. Pressure is lost during stop-start engine-off events.
Affected components
- Aux trans pump a
- Pump relay
- Wiring harness
Common causes
- High likelihood: Open pump motor winding
- Medium likelihood: Broken control wire
Possible symptoms
- Check engine or transmission warning light on
- Harsh, delayed, or missing shifts
- Possible limp mode (locked in one gear)
- Slipping or shuddering during gear changes
Diagnostic notes
- The malfunction indicator lamp may illuminate
Related codes
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.