X65 - DTC 1479: Check High Fan Control (HFC) Circuit

Continuous Memory Diagnostic Trouble Code (DTC) 1479 indicates that an HFC circuit failure has occurred during vehicle operation.

NOTE: For one speed fan applications disregard DTC 1479.

Possible Causes:
- Open or shorted HFC circuit.

- Key Off.

- Scan Tool connected.

- Disconnect cooling fan connector. Inspect connectors for damaged or pushed out pins, corrosion, loose wires, etc. Service as necessary.

- Connect a non-powered test lamp between the Power-to-High Speed Fan circuit and ground circuit at the cooling fan vehicle harness connector.

- Key On, Engine Off.

- Access Output Test Mode on Scan Tool. Output Test Mode

- Command High Speed Fan On.

- Observe test lamp for an indication of a fault while performing the following (the lamp will turn off when a fault is detected, indicated an open or short to power):
- Shake, wiggle, bend the HFC circuit between the PCM and CCRM.
- Lightly tap on the CCRM to simulate road shock.

- Is a fault indicated?

YES -- Key Off. ISOLATE fault and SERVICE as necessary. Complete PCM reset to clear DTCs. Clearing Diagnostic Trouble Codes

Rerun quick test. Diagnostic Subroutines (DSR) - Extracting Codes

NO -- GO to X66. X66 - Check HFC Circuit For Short to Ground