C 2500 Suburban 2WD V8-6.5L DSL Turbo VIN F (1995)
PROM - Programmable Read Only Memory: All Technical Service Bulletins
A/T - No Upshift After Cold Start, Intermittent DTC 87
File In Section: 7 - Transmission
Bulletin No.: 67-71-53A
Date: June, 1997
Subject:
No Upshift/2nd Gear Only After Cold Start-Intermittent DTC 87 - High Ratio Error (Replace EPROM)
Models:
1994-95
Chevrolet and GMC C, K, P Truck, G Van
1996
Chevrolet and GMC P Truck, G Van
equipped with HYDRA-MATIC 4L80E Automatic Transmission (RPO MT1)
This bulletin is being revised to add Part Numbers for Gasoline/Diesel engines that are TCM controlled parts and to include all Engine applications.
Please discard Corporate Bulletin Number 67-71-53 (Section 7 - Transmission).
Condition
Some owners may comment about no transmission upshift after a cold start. In conjunction, Diagnostic Trouble Code (DTC) 87 is setting intermittently
causing the PCM to command the default action of second gear only.
Cause
The commanded shift to third gear or fourth gear has taken longer than 2 seconds with a minimum 25% TP Sensor reading which has caused DTC 87 to
set.
Correction
If normal diagnostics fail to lead to a resolution or the condition cannot be duplicated, replace the EPROM.
Service Information/Procedure
