Diagnostic Aids

If Code 86 is intermittent, all circuits leading to the PCM that are connected to the A/D multiplexer should be checked for an intermittent short to battery voltage. Monitor each input circuit on a scan tester and wiggle related circuits (wiring and connectors). Any circuit that intermittently shorts to battery voltage will show a change in data on the scan tester.

Fig 1: Code 86: Analog/Digital Error Schematic

Fig 2: Code 86: Analog/Digital Error Flow Chart