Lost Communication With Engine Coolant Pump
The vehicle bus reports loss of communication with smart engine coolant pump (electric water pump). Pump speed cannot be commanded; coolant flow falls back to a default duty.
Affected components
- Engine coolant pump
- Vehicle bus wiring
Common causes
- High likelihood: Bus wiring open or shorted
- Medium likelihood: Module without power or ground
- Medium likelihood: Module failed
Possible symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Diagnostic notes
- The malfunction indicator lamp may illuminate
- A drive cycle may be required after repair
- Reduced-power or limp mode may occur
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.