Diagnostic Aids

An intermittent may be caused by a poor connection, rubbed-through wire insulation or a wire broken inside insulation. Inspect ECM harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal-to-wire connection and damaged harness.

If connections and harness are okay, connect a digital volt-ohmmeter between affected terminal to ground, and monitor meter while moving related connectors and wiring harness. If failure is induced, voltage reading will change.

Fig 1: Code 42, Schematic, EST Ckt Open or Grounded, Riviera

Fig 2: Code 42, Schematic, EST Ckt Open or Grounded, Toronado & Trofeo

Fig 3: Code 42, Flow Chart, EST Ckt Open or Grounded

Fig 4: Code 42