Diagnostic Aids

If Codes 22, 24 and 41 are also set, problem is open in sensor ground circuit.

An intermittent condition may be caused by poor connection, rubbed-through insulation, or a broken wire inside insulation. Check ECM harness connectors for backed-out, improperly mated, broken locks, improperly formed, or damaged terminals, and poor terminal-to-wire connections before component replacement.

Fig 1: Code 31 Schematic (Except LSi) MAP Sensor Circuit, Open Or Shorted Circuit

Fig 2: Code 31 Flow Chart (Except LSi) MAP Sensor Circuit, Open Or Shorted Circuit