What does it mean?
P1486 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Cooling Fan Output Circuit Low Voltage .
Symptoms
- MIL on
- Cooling fan runs constantly, even with a stone cold engine
- Warm up takes far longer and heater output is poor in cold weather
- Battery drain if the fan keeps running after the engine is switched off
- Slightly higher fuel consumption while the engine runs below normal temperature
Likely causes
- Cooling fan output circuit shorted to ground
- Fan relay coil shorted internally and holding the output low
- Control wire chafed and grounding against the engine or body
- Corrosion inside the relay socket bridging adjacent pins
- Water intrusion into the front harness connector
- Fan control module with a stuck low output
- Module driver shorted internally
How to fix it
- Command the fan output off with the scan tool and see whether the fan actually stops
- Unplug the relay and measure the resistance from the control wire to ground
- Inspect harness routing near the fan shroud and radiator for chafe points
- Test the relay coil for an internal short
- Dry and clean any water contaminated connectors, then reseal them properly
- Repair the shorted wire, or replace the relay or fan control module
- Confirm the fan now cycles normally with coolant temperature after the repair