Loss of Cruise Control, Decreased Pedal Dampening or Tip in Driveline Clunk (Inspect Wiring and NSBU Switch)
| Subject: | Loss of Cruise Control, Decreased Pedal Dampening or Tip In Driveline Clunk (Inspect Wiring and NSBU Switch) |
| Models: | 2001 Chevrolet Silverado Pickup Models |
| 2001 GMC Sierra Pickup Models |
| with 6.6L Duramax™ Diesel Engine (VIN 1 -RPO LB7) |
| and Allison® Automatic Transmission (RPO M74) |
Condition
Some customers may comment on a loss of cruise control function, decreased accelerator pedal dampening or a tip in driveline clunk noise. Additionally, the customer may perceive a change in the sound of the running engine.
Cause
Circuit 1786 ORN/BLK from the Park/Neutral Start Back-Up (NSBU) switch to the PCM may be shorted to ground, or the NSBU may not be switching correctly and grounding the circuit internally.
Correction
Using Service Manual procedures, repair any short to ground on the 1786 circuit or replace the Park/Neutral Start Back-Up Switch if internally shorted to ground. Also, be sure that the vehicle contains the latest PCM Calibration.
Warranty Information
For vehicles repaired under warranty, use:
Labor Operation | Description | Labor Time |
|---|---|---|
J6355 | Powertrain Controller - Reprogram | 0.4 hr |
N6630 | Transmission/Transfer Case/ Trans-Axle/Front and Rear Axle Control Wiring and or Connector Repair or Replace | 0.1-0.5 hr |
K5228 | Switch, Park/Neutral Position - Replace | 0.5 hr |
