Circuit Description
The ABS Diagnostic System Check is an organized approach to identify problems associated with the EBTCM. This check must be the starting point for any EBTCM complaint, and will direct you to the next logical step in diagnosing the complaint. The EBTCM 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 EBTCM test 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 EBTCM? | -- | Go to Step 3 | Go to Step 2 |
2 | Does the scan tool communicate with other modules on the class 2 line? | -- | Go to No Communication with Electronic Brake and Traction Control Module | Go to Scan Tool Does Not Communicate with Class 2 Data Line in Data Link Communications |
3 |
Are there any current DTCs? | -- | Go to Step 4 | |
4 |
Is the TRACTION OFF message displayed on the DIC? | -- | Go to Step 5 | |
5 | Press the traction control switch to disable traction control. Is the TRACTION OFF message displayed on the DIC? | -- | Go to Step 6 | |
6 | Are there any history DTCs? | -- | Go to Step 7 | |
7 | Is the Stabilitrak® inoperative? | -- | Go to Step 8 | |
8 | Is the Stabilitrak® active unwantedly? | -- | Go to Vehicle Stability Enhancement System Unwanted Activation | Go to Step 9 |
9 | Is there excessive brake pedal vibration during Stabilitrak® activation? | -- | Go to Vehicle Stability Enhancement System Excessive Brake Pulsation | System OK |
