Diagnostic Aids
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2002 Pontiac Grand Prix, 2002 Pontiac Bonneville, 2002 Chevrolet Monte Carlo, 2002 Chevrolet Impala, and 2002 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.
Check for skewed MAP signal. A skewed MAP signal may cause the PCM to incorrectly determine the TP sensor is out of range. Inspect for an unusually low or high MAP reading.
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 diagnosis may isolate cause of fault. See DTC P1121: TP SENSOR CIRCUIT INTERMITTENT - HIGH VOLTAGE .