Diagnostic Aids

WARNING: This page is about a different car, the 2002 Isuzu Trooper. However, it is still accessible from the selected car via links, so may be relevant.

Check for poor connection, rubbed-through wire insulation or a broken wire inside insulation. Inspect harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection, and damaged harness. If harness appears to be okay, use DVOM to observe suspect driver circuits at PCM while moving connectors and harnesses. See WIRING DIAGRAMS article. A change in display will indicate location of fault. Check for poor, loose or corroded terminals or harness connectors at: instrument cluster harness, canister purge solenoid, A/C clutch relay. An open circuit at and of these components will cause DTC P1650 to set. If DTC cannot be duplicated, check scan tool FAILURE RECORDS to determine mileage since last DTC was set. QDM controls voltage at PCM harness connector E-22 terminals No. 7 (EVAP canister purge valve) and No. 74 (variable intake manifold vacuum switching valve).