Hydraulic Pump Relay Circuit/Open
Open circuit at the auxiliary hydraulic pump relay used to maintain transmission line pressure during start-stop or hybrid operation.
Affected components
- Hydraulic pump relay
- Auxiliary hydraulic pump
- Wiring harness
Common causes
- High likelihood: Relay coil open
- Medium likelihood: Wiring break
- Low likelihood: Pin pushed back out of connector body
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
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.