Diagnostic Aids
WARNING: This page does not describe the selected car, but rather 11 other vehicles, including the 2002 GMC Yukon XL, 2002 GMC Yukon, 2002 GMC Sierra, 2002 GMC Cab & Chassis Sierra, and 2002 Chevrolet Tahoe. However, it is still accessible from the selected car via links, so may be relevant.
Inspect for the following conditions:
- A skewed MAP sensor. A skewed MAP signal may cause the PCM to incorrectly determine that the TP sensor is out of range. Inspect for an unusually low or unusually high MAP reading.
- If the DTC is determined to be intermittent, or the TP sensor system is still suspect, see DTC P1121: TP SENSOR CIRCUIT - INTERMITTENT HIGH VOLTAGE and INTERMITTENT CONDITIONS under SELF-DIAGNOSTIC SYSTEM.