RWAL Brakes - Repeated Code 4
90chevy28Number: 90-282-5
Section: 5
Date: June 1990
Corp.Bulletin No.: 065002R
Subject: GROUNDED VALVE RESET SWITCH CIRCUIT REPEAT CODE 4
Model and Year: 1990 G VAN WITH RWAL BRAKES
RWAL Trouble Code 4 Diagnosis Chart:
TO: ALL CHEVROLET DEALERS
Incidents of repeated code 4 conditions may be observed on the above vehicles. This condition can be caused by contamination of the dual coil electrical connector which is part of the RWAL control valve assembly. The contamination can cause a short to ground within the connector resulting in a code 4 being set and deactivation of the anti-lock feature of the RWAL System. A new dual coil connector has been released which prevents water and contamination intrusion into the connector. The new connector can be identified by its natural whitish/yellow color. All previous connectors have been black.
Figure No. 1:
IMPORTANT: The dual coil connector is manufactured as an integral component of the RWAL control valve assembly therefore the control valve must be replaced as a unit (see Figure 1).
DIAGNOSIS INFORMATION
Technicians should refer to the RVGP Light Duty Truck Service Manual for correct diagnostic procedures. If the connector is the cause of the Code 4, the manual will identify the control valve assembly as the probable cause. See attached Code 4 diagnosis chart.
When the control valve has been replaced the technician should clear all codes, and assure that no other codes are set by performing a function test and Diagnostic Circuit Check.
Figure No. 2:
IMPORTANT: The wiring diagram for control valve to the ECU is given in Figure 2. This diagram shows the correct wire/color sequence and connections.
PARTS INFORMATION
Description Part Number Model
Control valve - pressure limit 15635214 G3 WITH JB7 BRAKES
15633174 G3 WITH JD7 BRAKES
G3 WITH JB8 BRAKES
15633176 G1 AND G2
Parts are currently available from GMSPO.
LABOR OPERATION INFORMATION
For vehicles repaired under warranty use:
Labor Operation: H2480
Labor Time: Use time as indicated in the labor time guide.