On-Board Diagnostics

The TCU has a built-in self-diagnostic system. It constantly monitors the speed sensor, solenoid valves and their circuitry, and stores failure data in its long-term memory. This memory can store up to 3 faults, which can be accessed through the use of a DRB-II tester. To properly interface with Jeep/Eagle vehicles, the DRB-II must be attached through an adapter.