Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSGMC1992JIMMY BASE, 2D UTILITY, 4.3 W, RWD, AUTOMATICREPAIR AND DIAGNOSIS (SINGLE PAGE)BRAKESANTI-LOCK BRAKESANTI-LOCK BRAKE SYSTEM - 4-WHEELDIAGNOSIS & TESTINGRETRIEVING CODES
1992 GMC Jimmy Base, 2D Utility, 4.3 W, RWD, Automatic
Retrieving Codes
1992 GMC Jimmy Base, 2D Utility, 4.3 W, RWD, AutomaticSECTION Retrieving Codes
NOTE:
Perform DIAGNOSTIC CIRCUIT CHECK chart under TROUBLE SHOOTING CHARTS . See Figure.
- If using Tech 1 for retrieving codes, go to step 3). If using ANTILOCK light for retrieving codes, turn ignition on. Using a jumper wire, connect terminal "H" to terminal "A" in ALDL connector. See Fig 1. System will repeat trouble code(s) as long as ALDL connector terminals are jumpered.
- Trouble codes will begin displaying by a flashing ANTILOCK warning light. As an example, Code 25 would be displayed by ANTILOCK warning light flashing 2 times, followed by a pause, then flashing 5 more times. See 4WAL FAULT CODES table for diagnosis. See CLEARING FAULT CODES to erase stored trouble codes. If no fault codes are present, see 4WAL SYMPTOM DIAGNOSIS table.
- Turn ignition off. Connect Tech 1 to ALDL connector. Access 4WAL brake trouble codes with Tech 1. Tech 1 will display trouble code(s). Repair trouble codes in order they appear. See 4WAL FAULT CODES table for diagnosis. See CLEARING FAULT CODES for erasing stored trouble codes. If no fault codes are present, see 4WAL SYMPTOM DIAGNOSIS table.
4WAL SYMPTOM DIAGNOSIS
| Symptom | Perform Chart | ||
|---|---|---|---|
| ANTILOCK Light On | ANTILOCK LIGHT ON (Fig. Figure) | ||
| ANTILOCK Light Off | ANTILOCK LIGHT OFF (Fig. Figure) | ||
| Brake Pedal Pulses (1) | BRAKE PEDAL PULSES (Fig. Figure) | ||
| Wheel Pull During Hard Braking (1) | WHEEL PULL DURING HARD BRAKING (Fig. Figure) | ||
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4WAL FAULT CODES
| Fault Code | Description | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 21, 25, 31 or 35 (1) | Speed Sensor Failure Or Open Circuit | ||||||||||
| 22, 26, 32 Or 36 (2) | Missing Speed Signal | ||||||||||
| 23, 27, 33 Or 37 (3) | Erratic Speed Sensor | ||||||||||
| 28 | Erratic Speed Sensor Signal (2 Dropouts Above 20 MPH) | ||||||||||
| 29 | Simultaneous Dropout Of All 4 Speed Sensors Above 8 MPH | ||||||||||
| 35 (4) | Speed Sensor Failure Or Open Circuit | ||||||||||
| 36 (4) | Missing Speed Sensor Signal | ||||||||||
| 37 (4) | Erratic Speed Sensor Signal | ||||||||||
| 38 | Speed Sensor Error | ||||||||||
| 41-54 | Control Valves | ||||||||||
| 61, 62 Or 63 | Reset Switches | ||||||||||
| 65 & 66 | Motor Relay Open Or Shorted | ||||||||||
| 67 (5) | Pump Motor Circuit Open Or EHCU Output Shorted | ||||||||||
| 68 (5) | Pump Motor Locked Or Motor Circuit Shorted | ||||||||||
| 71-74 | Memory Errors | ||||||||||
| 81 | Brake Switch Circuit Open Or Shorted | ||||||||||
| 86 | ANTILOCK Light Shorted | ||||||||||
| 88 | BRAKE Light Shorted | ||||||||||
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RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.