X66 - Check HFC Circuit For Short to Ground

- Key On, Engine Off.

- Cooling fan disconnected, test lamp installed.

- Scan Tool connected.

- Command High Speed Fan Off.

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

- Key Off.

- Is a fault indicated?

YES -- 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 Pinpoint Test Step Z1 with the following data: HFCA PID and list of Possible Causes. Z1 - Intermittent Test Procedure