Diagnostic Procedures

WARNING: This page does not describe the selected car, but rather 13 other vehicles, including the 2003 Hummer H2, 2003 GMC Yukon XL, 2003 GMC Yukon, 2003 GMC Sierra, and 2003 GMC Cab & Chassis Sierra. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: DTC P2121: APP Sensor Circuits Out Of Correlation (Steps 1-9)

Courtesy of GENERAL MOTORS CORP.

Fig 2: DTC P2121: APP Sensor Circuits Out Of Correlation (Steps 10-19)

Courtesy of GENERAL MOTORS CORP.