Cooling Fan Power/Ground Circuit Malfunction
The PCM detected a malfunction in the cooling fan control circuit, such as an open circuit, short to power, or short to ground between the fan module and engine control unit. This prevents proper cooling fan operation, which could lead to engine overheating if left unaddressed.
What You Might Notice
- Cooling fan runs continuously or not at all
- Engine temperature gauge reads higher than normal
- Engine overheating warning light may illuminate
- Reduced air conditioning efficiency
- Check Engine light (MIL) illuminated
Most Common Causes
- 1
Cooling fan module failure
The cooling fan module itself has failed electrically and cannot respond to PCM commands. This is the most common cause of this code.
- 2
Open or broken wire in fan control circuit
The wiring between the PCM and cooling fan module is disconnected, broken, or corroded, preventing signal transmission.
- 3
Short to power or ground on fan circuit
A wire in the fan control circuit has shorted to power or ground, causing voltage irregularities that the PCM detects as a fault.
- 4
Faulty PCM or internal wiring
Less commonly, the PCM itself has an internal failure in the cooling fan control circuit or associated components.
How to Diagnose It
- 1
Check Cooling fan module failure — The cooling fan module itself has failed electrically and cannot respond to PCM commands. This is the most common cause of this code.
- 2
Check Open or broken wire in fan control circuit — The wiring between the PCM and cooling fan module is disconnected, broken, or corroded, preventing signal transmission.
- 3
Check Short to power or ground on fan circuit — A wire in the fan control circuit has shorted to power or ground, causing voltage irregularities that the PCM detects as a fault.
- 4
Check Faulty PCM or internal wiring — Less commonly, the PCM itself has an internal failure in the cooling fan control circuit or associated components.
How to Fix It
- 1
Test and replace cooling fan module
Use a multimeter to verify power and ground at the fan module connector. If voltage is present but the fan doesn't run, replace the cooling fan module.
- 2
Inspect and repair wiring harness
Check the wiring between the PCM and cooling fan module for breaks, corrosion, or loose connections. Repair or replace damaged sections and ensure all connectors are clean and tight.
- 3
Check PCM power and ground circuits
Verify that the PCM is receiving proper power and ground. Test continuity on the fan control circuit wiring from the PCM to the fan module using a multimeter.
- 4
Replace PCM if internal failure confirmed
If all external circuits test good but the fault persists, the PCM may have an internal failure and will need replacement and reprogramming.
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