Electric/Auxiliary Transmission Fluid Pump B Stuck On
The second auxiliary transmission fluid pump runs even when no command is active.
Affected components
- Aux trans pump b
- Control module
- Wiring harness
Common causes
- High likelihood: TCM output driver stuck on
- Medium likelihood: Control wire shorted to a permanent B+ supply
- Low likelihood: Carbon or debris buildup preventing free movement
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.