Diagnostic Aids

2003 Chevrolet TrailBlazer 4.2 S, 4WDSECTION Diagnostic Aids
WARNING: This page is about a different car, the 2002 Pontiac Aztek and 2002 Buick Rendezvous. 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 VOLTAGEΒ  and INTERMITTENT CONDITIONSΒ  under SELF-DIAGNOSTIC SYSTEM.

RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.