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Home >> GMC >> 2002 >> C3500 HD 8.1 G, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - 8.1L >> Diagnostic Information and Procedures >> DTC P1276 >> Test Description

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. 2. This step determines if a communication condition exists.
  2. 5. This step isolates an internal APP sensor failure. The condition may only occur at a certain accelerator pedal position. Monitoring the APP angles for sensor 2 and sensor 3 is an accurate way of verifying the actual position of the pedal. The APP angles for all 3 sensors should be within a few percent of each other. When the pedal is at rest the APP angle for all 3 sensors should be 0 percent, when the pedal is fully depressed all APP angles should be 100 percent.
  3. 6. The APP sensor 1 shares a common 5 volt reference circuit with the TP sensor 1. Monitoring the TP sensor 1 voltage aids in diagnosing the APP sensor 5-volt reference and low reference circuits. If the scan tool displays near 0 volts, the circuits are OK.
  4. 9. With the TAC module still connected, this test will help determine a short to the signal circuit either within the TAC module or wiring.
  5. 10. This step determines whether the TAC module or a shorted circuit is causing the condition.
  6. 19. When the TAC module detects a condition within the TAC system, more than one TAC system related DTC may set. This is due to the many redundant tests run continuously on this system. Locating and repairing one individual condition may correct more than one DTC. Disconnecting components during testing may set additional DTCs. Keep this in mind when reviewing the stored information, Capture Info.
Fig 1: DTC P1276 (1 Of 3)
G01599093Courtesy of GENERAL MOTORS CORP.
Fig 2: DTC P1276 (2 Of 3)
G01599094Courtesy of GENERAL MOTORS CORP.
Fig 3: DTC P1276 (3 Of 3)
G01599095Courtesy of GENERAL MOTORS CORP.