Fail-Safe And Diagnostic Functions

The TCL/ASC-ECU regularly monitors input and output signals. If an error is detected in the system, the ECU sends a fail signal and the TCL/ASC indicator is illuminated or blinks. Various controls are processed depending on the cause of malfunction as shown in the illustration below. When the ABS system fails, the TCL/ASC system is also suspended. However, when the TCL/ASC system fails, no other system is suspended. The appropriate indicator lights are illuminated/flashed.

The TCL/ASC-ECU includes the following functions to make system inspection easier.

• Diagnostic trouble code
• Displays Data list
• Actuator test

All of the above operations can be carried out using scan tool MB991958.