What does it mean?
P1488 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: After Run Coolant Pump Control Circuit Low .
Symptoms
- MIL on
- The after run pump operates continuously, even with a cold engine
- Battery discharges because the pump keeps running with the key off
- Audible humming from the pump long after the engine is shut down
- Slow warm up and reduced heater performance
- The circuit fuse may blow in some cases
Likely causes
- After run coolant pump control circuit shorted to ground
- Pump relay coil shorted internally
- Control wire chafed and grounding against the body or engine
- Corrosion bridging terminals in the pump or relay connector
- Water intrusion into an underhood connector in the circuit
- Module driver stuck low from an internal failure
- Incorrect or damaged aftermarket wiring spliced into the circuit
How to fix it
- Confirm whether the pump is running at times when it should be off
- Unplug the relay or the pump and measure the control wire resistance to ground
- Inspect the harness routing for chafe points and repair any damaged insulation
- Test the relay coil for an internal short
- Clean and dry corroded connectors, then reseal them against water
- Replace the relay or the pump if either tests shorted
- Clear the code and verify the pump only runs during its normal after run period