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 scan tool to observe TPS1 display while moving connectors and harnesses. A change in display will indicate location of fault. Using wiring diagrams to determine if TPS 1 shares common power or ground points may aid in diagnostic. See WIRING DIAGRAMS article. If DTC P1120 cannot be duplicated, check scan tool FAILURE RECORDS to determine mileage since last DTC was set.