Description of On-Board Diagnostics

The RWAL system performs a self-check every time the ignition key is turned from OFF to ON position. The system check consists of the following:

1. Checks the rear anti-lock light by illuminating for approximately two seconds.
2. Checks all of the electrical circuits for shorts or opens.
3. Checks the RWAL system operation by activating the isolation valve and dump valve.
If a malfunction is detected in any of these tests, the electronic control module (ECM) will cancel the anti-lock function, illuminate the anti-lock brake system warning lamp, and generate a related Diagnostic Trouble Code (DTC) to be stored in memory, for later diagnosis and testing procedures.

In the rare event that a self shutdown of the RWAL system cannot occur, the ECM will melt an internal fuse pellet. This will prevent the system from operating.