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.
Retrieving DTCS
Turn ignition off. Connect Tech 1 scan tool to DLC and retrieve DTCs. Repair DTCs in order they appear. See 4WAL FAULT CODES table for diagnosis. If no fault codes are present, see 4WAL SYMPTOM DIAGNOSIS table.
The scan tool has 5 modes to assist in diagnosing 4WAL system. After selecting 4WAL from the select system menu, scan tool will automatically display SELECT MODE menu. From this menu, one of the 5 test modes can be selected by pressing appropriate key. The 5 test modes are:
- MODE F0: DATA LIST This mode allows continuous monitoring of 4WAL parameters. Scan tool displays data parameters in pairs. The parameters and its values will be displayed. The scan tool can be programmed to display specific pairs of parameters by following the screen commands, allowing you to monitor specific values that are not normally displayed together.
- MODE F1: FUNCTION TEST This mode allows actuation of 4WAL system. Scan tool sends a signal to the EBCM that causes it to cycle the system. For a short period, the EBCM will cycle the valve and activate the pump motor.
- MODE F2: DTCS This mode allows access and clearing DTCs. The screen will display the DTC and a brief description of what it represents.
- MODE F3: SNAPSHOT This mode helps isolate an intermittent condition. You can specify a trigger condition or manually trap the data. The scan tool captures and stores data before and after the trigger. Snapshot mode is divided into 3 phases; setup, data capture and data display.
- MODE F4: MISC. TESTS This mode allows researching the PROM ID to see which version of software is used in the EBTCM, history data, history codes, and tire size calibration.
| DTC | Description |
|---|---|
| 21 | Right Front Wheel Speed Sensor Circuit Open |
| 22 | Right Front Wheel Speed Sensor Signal Missing |
| 23 | Erratic Right Front Wheel Speed Sensor Signal |
| 25 | Left Front Wheel Speed Sensor Circuit Open |
| 26 | Left Front Wheel Speed Sensor Signal Missing |
| 27 | Erratic Left Front Wheel Speed Sensor Signal |
| 29 | Simultaneous Signal Drop-out Of Front Wheel Speed Sensors |
| 35 | Open Or Grounded Rear Wheel Speed Sensor Circuit |
| 36 | Missing Rear Wheel Speed Sensor Signal |
| 37 | Erratic Rear Wheel Speed Sensor Signal |
| 38 | Wheel Speed Error |
| 41 | BPMV Control Valves |
| 42 | BPMV Control Valves |
| 43 | BPMV Control Valves |
| 44 | BPMV Control Valves |
| 45 | BPMV Control Valves |
| 46 | BPMV Control Valves |
| 47 | BPMV Control Valves |
| 48 | BPMV Control Valves |
| 49 | BPMV Control Valves |
| 50 | BPMV Control Valves |
| 51 | BPMV Control Valves |
| 52 | BPMV Control Valves |
| 53 | BPMV Control Valves |
| 54 | BPMV Control Valves |
| 65 | Open Or Shorted Pump Motor Relay |
| 66 | Open Or Shorted Pump Motor Relay |
| 67 | Open Pump Motor Circuit Or Shorted EBCM Output |
| 68 | Locked Motor Or Shorted Motor Circuit |
| 71 | EBCM Memory Errors |
| 72 | EBCM Memory Errors |
| 73 | EBCM Memory Errors |
| 74 | EBCM Memory Errors |
| 81 | Brake Switch Circuit Open Or Shorted |
| 86 | Shorted ABS Indicator Light |
| 88 | Shorted Brake Warning Light |
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.