A/T - Wide Open Throttle 1-2 Double Bump/Harsh Shift

File In Section 06 - Engine/Propulsion System

Bulletin No.: 99-06-04-049

Date: October, 1999

TECHNICAL

Subject:
Wide Open Throttle (WOT) 1-2 Double Bump and/or Harsh Upshift (Reprogram PCM)

Models:
2000 Chevrolet and GMC C/K Models (Silverado and Sierra) With 4.8 L Engine (VIN V - RPO LR4) and 4L60-E Automatic Transmission (RPO M30) Built Prior to the following VIN Breakpoints:

Plant VIN Breakpoint

Pontiac East YE124221
Fort Wayne YZ124556
Oshawa Y1108340

Condition

Some customers may comment on a double bump or harsh shift when making a wide open throttle (WOT) 1-2 upshift.

Cause

Some early built 2000 model year production Siverado and Sierra pickups, with the 4.8 L engine and the 4L60-E automatic transmission, were built with an engine calibration that may place the engine fuel cut-off RPM too close to the transmission 1-2 WOT upshift point.

Correction

A new calibration has been released, raising the engine fuel cut-off to 6000 RPM. Reprogram the PCM with the new calibration listed below.

Parts Information

Previous New
Calibration Calibration Description

16263681 9357621 C/K 10 003-53
and LR4 and M30

The calibration listed is an electronic calibration and is NOT available from GMSPO. The calibration will be available from Techline starting August 12,1999, on the TIS 2000 Disc 17 CD ROM.

Warranty Information

For vehicles repaired under warranty, use:

Labor
Operation Description Labor Time

J6355 Prom-Reprogramming Use published
On Vehicle labor operation
time