Trouble Shooting
NOTE:
Only "S" and "T" Series pickup equipped with 4.3L and manual transmission use a Vehicle Control Module (VCM) to control RWAL system. All other vehicles use an Electronic Brake Control Module (EBCM) to control RWAL system.
SYMPTOM DIAGNOSIS
| Symptom | Go to Figure No. | |
|---|---|---|
| Except VCM Controlled RWAL | ||
| Functional Test | 4 | |
| BRAKE Light On | 5 | |
| Intermittent BRAKE Light | 8 | |
| BRAKE Light Flashing | 9 | |
| BRAKE Light Off | 10 | |
| VCM Controlled RWAL | ||
| Functional Test | 22 | |
| BRAKE Light On | 23 | |
| Intermittent BRAKE Light | 24 | |
| BRAKE Light Flashing | 25 | |
| BRAKE Light Off | 26 | |
TROUBLE CODES
| Code | Description |
|---|---|
| 2 | Open Isolation Solenoid Or EBCM Malfunction |
| 3 | Open Dump Solenoid Or EBCM Malfunction |
| 4 | Grounded Anti-Lock Pressure Valve Reset Switch |
| 5 | Excessive Dump Valve Actuations During An Anti-Lock Stop |
| 6 | Erratic Speed Signal |
| 7 | Shorted Isolation Solenoid Or EBCM Malfunction |
| 8 | Shorted Dump Solenoid Or EBCM Malfunction |
| 9 | Open Or Grounded Speed Signal Circuit |
| 10 | Brake Light Switch Circuit |
| 1, 11 & 12 | Invalid Diagnostic Trouble Codes |
| 13, 14 & 15 | EBCM Malfunction |
TROUBLE CODES
| Code | Description |
|---|---|
| 2 | Open Isolation Solenoid Or VCM Malfunction |
| 3 | Open Dump Solenoid Or VCM Malfunction |
| 4 | Grounded Anti-Lock Pressure Valve Reset Switch |
| 5 | Excessive Dump Valve Actuations During An Anti-Lock Stop |
| 6 | Erratic Speed Sensor Signal |
| 7 | Shorted Isolation Solenoid Or VCM Malfunction |
| 8 | Shorted Dump Solenoid Or VCM Malfunction |
| 9 | Vehicle Speed Sensor Input Missing |
| 10 | Brake Switch Circuit |
| 17 | Brake Enable Relay Circuit |