Electric/Auxiliary Transmission Fluid Pump B Hydraulic Leakage
The second auxiliary transmission fluid pump cannot maintain pressure even at high duty cycle. Indicates internal hydraulic leakage downstream of the pump.
Affected components
- Aux trans pump b
- Hydraulic circuit
- Valve body seals
Common causes
- High likelihood: Worn or hardened seals downstream of pump
- Medium likelihood: Pressure relief or bypass valve stuck open
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.