Fault Description
Engine cooling system, low power operation: coolant pump supply voltage too low.
Fault Cause Analysis
The diagnostic system monitors the coolant pump status. If ‘operation without lubrication’ is detected, this fault will be identified.
Fault Troubleshooting Method (in sequence)
- Check whether the vehicle battery voltage is within the normal range (after starting, the voltage should be between 12–14V).
- Disconnect the coolant pump connector and inspect for oxidation or burn marks. Measure the supply voltage at the connector terminals (the two thickest wires).
- If the voltage is different from the battery voltage, inspect the wiring.
- If the voltage is the same, check the contact resistance between the connector and the pump plug, or directly replace the harness connector. In most cases, this resolves the fault.
- Replace the coolant pump with the same model.
