Express 3/4 Ton Van V8-6.5L DSL Turbo VIN F (1999)
Accelerator Pedal: Customer Interest
Fuel - Reduced Power, Various DTCs May Be Present
File In Section: 06 - Engine/Propulsion System
Bulletin No.: 99-06-04-039
Date: September, 1999
TECHNICAL
Subject:
Reduced Engine Power, DTC(s) P1125, P1275, P1276, P1280, P1281, P1285, and/or P1286 May be Present [Current or in History]
(Replace Accelerator Pedal Assembly)
Models:
1999 Chevrolet and GMC B7 Models
with 7.4L Engine (VINs B, D - RPOs L21, LP4)
1999 Chevrolet and GMC G2-3 Van Models
with 6.5L Diesel Engine (VIN F - RPO L65)
Condition
Some owners/operators may comment about reduced engine power. During this condition, the REDUCED ENGINE POWER lamp/message illuminates
and powertrain control module (PCM) Diagnostic Trouble Codes (DTC) for the throttle actuator control (TAC) system are set. Cycling the ignition key
to the "OFF" position for 15 seconds or more will reset the PCM allowing normal engine operation until the condition recurs.
The DTCs set will be for the accelerator pedal position (APP) sensor and may consist of one or more of the following DTCs: P1125, P1275, P1276,
P1280, P1281, P1285 or P1286.
Cause
An incorrect signal from the APP sensor may cause this condition. The TAC module monitors three sensor inputs generated from the APP sensor. If one
of these inputs is incorrect, the TAC module will default the PCM to control the engine in a reduced power mode. This reduced power mode will only
allow a maximum throttle angle of approximately 16 percent.
Correction
Replace the accelerator pedal assembly, which includes the APP sensor, on affected vehicles. Use the following procedure and the appropriate part
number listed below.
Accelerator Pedal and Bracket Assembly (B Models)
