mm28 Anti Lock Braking Systems ABS for Trucks, Tractors, and Buses C Version

3 Troubleshooting

Step

Condition

Cause

Action

I, III

Code continues to repeat.

Ignition and blink code switch not turned off.

Turn Blink Code switch off. Wait for lamp to stop flashing. Turn Ignition off.

Fault not repaired.

Review Diagnostics Chart or TP-94157 to ensure all possible conditions were corrected. Verify all repair work.

Fault not erased from ECU after report.

Repeat procedure until System O.K. code received.

II

Code not listed on Diagnostics Chart or TP-94157.

Blink Code Diagnostics Use the following charts to identify blink codes.

Table D: Blink Codes

Additional 6S/6M and 6S/4M blink codes follow this table. Fault Code Blink Code 1 Location Cause

Solution

1-0-0 2-0-0 4-0-0 1-6-6 2-6-6 4-6-6 1-6-7 2-6-7 4-6-7 1-6-8 2-6-8 4-6-8 1-6-9 2-6-9 4-6-9

N/A

No Faults — System O.K.

No action needed.

Voltage Relay 1

Low voltage to the diagonal relay or defective relay.

Check vehicle voltage or replace relay if needed.

Voltage Relay 2

Right Front Wheel

Erratic wheel speed signal from the steering axle.

Check for loose wheel bearings, faulty sensor wiring connections, excessive hub runout, a sensor gap that is too wide, or damage to tooth wheels on the steering axle.

Left Front Wheel

WABCO Maintenance Manual MM-28 (Revised 03.2020)

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