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Diagnostic Aids

Check for faulty connections or damaged harness. Ensure harness is not routed too close to high-voltage wires, such as spark plug cables. If connections and harness appear okay, observe scan tool while moving all related harness and connectors. A change in scan tool display indicates fault location. Check for skewed MAP signal or faulty MAP sensor.

If DTC cannot be duplicated, the information included in the FAILURE RECORDS data can be useful in determining vehicle mileage since DTC was last set. If it is determined that DTC is intermittent, performing DTC P1121 and P1122 diagnosis may isolate cause of fault.

Fig 1: Identifying Throttle Position Sensor Connector
G00058833Courtesy of GENERAL MOTORS CORP.