Test Aa: No Communication With COMPUVALVE (Bi-Fuel Only)
- Turn ignition switch to LOCK position. Disconnect compuvalve connector C4025. Turn ignition switch to RUN position. Measure voltage between ground and terminal No. 2 (White wire) at compuvalve harness connector C4025. See Fig 1. Measure voltage between ground and terminal No. 11 (White wire) at compuvalve harness connector C4025. If battery voltage is present, go to next step. If battery voltage is not present, repair open circuit in appropriate White wire(s).
- Turn ignition switch to LOCK position. Measure resistance between ground and terminal No. 64 (Black wire) at compuvalve harness connector C4025. If resistance is 5 ohms or less, see
MODULE COMMUNICATIONS NETWORK - EXCURSION & F250-F550 SUPER DUTY PICKUPS article. If resistance is more than 5 ohms, repair open in Black wire and retest.
Courtesy of FORD MOTOR CO.