75 - ECU Internal Failure

ECU INTERNAL FAILURE-75
For a complete wiring diagram, refer to Wiring Diagram Information.

When Monitored
- Ignition on.

Set Condition
When the CAB internal micro processor has an open/short in the status line which fails to transmit at the correct frequency.

Possible Causes
- WHEEL SPEED SENSOR FAILURE
- CONTROLLER ANTI-LOCK BRAKE

Diagnostic Test
1. VERIFYING DTC

NOTE: Before continuing, check the Controller Anti-lock Brake harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary. Turn the ignition on. With the DRBIII (R) erase DTC's. Turn the ignition off. Turn the ignition on.

NOTE: Ensure that the Wheel Speed sensor are working properly. With the DRBIII (R) read DTC's.

Does the DRBIII (R) display ECU INTERNAL FAILURE and a WHEEL SPEED SENSOR DTC'S?
Yes >> Refer to the symptom list and diagnose the display Wheel Speed DTC.
Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test
No >> Replace the Controller Anti-lock Brake in accordance with the Service Information. Refer to the symptom *Replacing the Controller Anti-Lock Brake.
Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test