The fuel pumps work fine if connected directly to the battery with jumpers to the sending units, but when in the tanks or otherwise connected through the wiring harness neither pump will engage. The EEC-IV self test code is # 542 "Fuel pump secondary circuit failure PCM to ground" according to the Chiltons manual for the truck. Also when testing the fuel tank selector switch the readings are incorrect. Where do I go from here other than trying to trace every possible wire for shorts?
Jan 2, 2010 at 8:57 PM