Much like the Powertrain Control Module (PCM), the ABS system is capable of storing Diagnostic Trouble Codes (DTCs) which can be accessed using the HDS, or a suitable 16-pin Data Scan Tool (DST).
If the Anti-lock Braking System (ABS) is OK, the ABS indicator lamp will light and then go out two seconds after turning the ignition switch to the ON position. The ABS lamp may illuminate a second time and then go off again. This is also normal.
The ABS lamp may illuminate under the below conditions.
The ABS lamp may or may not stay illuminated continuously if a fault is detected. It depends which DTC was detected and if the system corrected the problem or not. The ABS lamp may go off only after the problem is corrected and the vehicle has been restarted and driven a few miles. Remember it depends on which code was thrown and the duration or number of times that the code was detected.
This system can perform an initial diagnosis and a regular diagnosis. The initial diagnosis is performed immediately after the engine is started and continues until the ABS lamp goes out. The regular diagnosis is performed after the initial system check and monitors the system constantly until the ignition switch is turned OFF .