A/T - No Upshift/Stuck in 1ST/No Codes/Exterior Leaks
BULLETIN NUMBER: 93-7A-58SECTION: 7A
NUMBER: 10
CORPORATE REFERENCE NUMBER: 377118
DATE: April 1993
SUBJECT:
NO UPSHIFT/STUCK IN FIRST/NO CODES/EXTERIOR LEAKS (REPLACE [1][2]SPEED SENSOR)
MODELS:
1991-93 C/K, R/V, P, AND G VEHICLES WITH 4L8O-E/4L80-EHD TRANSMISSIONS
CONDITION
Some 1991-93 C/K, R/V, P, and G Vehicles With 4L80-E/4L80-EHD transmissions may experience a no upshift, stuck in first with no Diagnostic Trouble Codes (DTC) stored.
CAUSE
Input/output speed sensor malfunction, or leaking (wicking) fluid through the [1][2]speed sensor connector (internal and/or external). If the input speed sensor is not functioning correctly, the output speed sensor is not used for reference by the PCM/TCM and an upshift cannot occur.
CORRECTION
Diagnose per the input speed sensor circuit check as outlined in Section 7A of the appropriate service manual. Replace the [1][2]speed sensor if necessary.
DATE OF PRODUCTION: (Figure 1)
Starting January 15, 1993 (Julian Date 015) all 1993 C/K, R/V, P, and G Vehicles With 4L80-E/4L80-EHD transmissions will have the new [1][2]speed sensor assemblies.
SERVICE PARTS INFORMATION
Part # Description
8685042 [1][2]Speed Sensor Assembly
WARRANTY INFORMATION
For vehicles repaired under warranty, use:
Labor Codes:
Replace input sensor K6311 or output sensor K6312.
Parts are expected to be available on March 22, 1993.