Diagnostic Aids

The "Scan" tester cannot help diagnose a Code 42 problem. See INTERMITTENTS in H - TESTING W/O CODES article.

Fig 1: Code 42: EST With HEI Ignition Circuit Diagram

Fig 2: Code 42: EST With HEI Ignition Flow Chart (All But R/V & G/P Models)

Fig 3: Code 42: EST With HEI Ignition Flow Chart (R/V & G/P Models)