Circuit Description
The ABS Diagnostic System Check is an organized approach to identify problems associated with the EBCM. This check must be the starting point for any EBCM complaint and will direct you to the next logical step in diagnosing the complaint. The EBCM is a very reliable component and is not likely the cause of the malfunction. Most system complaints are linked to faulty wiring, connectors, and occasionally to components. Understanding the ABS system and using the tables correctly will reduce diagnostic time and prevent unnecessary parts replacement.
Diagnostic Aids
| • | An intermittent failure in the electronic system may be very difficult to detect and to accurately diagnose. The EBCM tests for different malfunctions under different vehicle conditions. For this reason, a thorough test drive is often needed in order to repeat a malfunction. If the system malfunction is not repeated during the test drive, a good description of the complaint may be very useful in locating an intermittent malfunction. Faulty electrical connections or wiring causes most intermitting problems. When an intermitting condition is suspected, check the suspected circuits for the following conditions: |
| - | Poor mating of connector halves or backed out terminals |
| - | Improperly formed or damaged terminals |
| - | Wire chafing |
| - | Poor wire to terminal connections |
| - | Dirty or corroded terminals |
| - | Damage to connector bodies |
| • | If the DTC is a history DTC, the problem may be intermittent. Perform the tests shown while moving related wiring and connectors. This can often cause the malfunction to occur. Perform a thorough inspection of all related wiring and connectors pertaining to the history DTC stored. Refer to General Electrical Diagnosis in Wiring Systems. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 |
Does the Scan Tool communicate with the EBCM? | -- | Go to Step 3 | Go to Step 2 |
2 | Does the scan tool communicate with other modules on the serial data line? | -- | Go to Scan Tool Does Not Communicate with Electronic Brake Control Module in Data Link Communications | Go to Diagnostic Starting Point - Data Link Communications in Data Link Communications. |
3 |
Are there any current Diagnostic Trouble Codes? | -- | Go to Applicable DTC Table | Go to Step 4 |
4 | Cycle the ignition switch from the OFF to ON position. Does the ABS Indicator come ON then go OFF after several seconds? | -- | Go to Step 6 | Go to Step 5 |
5 | Does the ABS Indicator come ON and stay ON? | -- | Go to ABS Indicator Always On | |
6 | Are there any History DTCs? | -- | Go to Step 7 | System OK |
7 |
Did the History DTC set as a current DTC while the vehicle was being driven? | -- | Go to Applicable DTC Table | System OK |
