The Diagnostic System Check is an organized method of identifying any problems caused by a malfunction in the ABS/DDRP system.
A service technician should begin diagnosis of any ABS/DDRP complaint with the Diagnostic System Check. The Diagnostic System Check directs a service technician to the next logical step when diagnosing a complaint.
Serial data is transmitted/received by the electronic brake control module (EBCM) through terminal 21. The EBCM is supplied with constant battery feed voltage through terminals 1 and 2, and switched ignition voltage through terminal 13. The EBCM ground is provided through terminal 14 and 15.
Serial data is transmitted/received by the EBCM through terminal 7. The EBCM is supplied with constant battery feed voltage through terminals 9 and 25, and switched ignition voltage through terminal 4. The EBCM ground is provided through terminal 8 and 24.
Use the following ordered procedure when servicing the ABS/DDRP system:
• | Verify the brake reservoir fluid level is correct. |
• | Inspect the master for fluid contamination. |
• | Inspect the brake master/modulator for leaks. |
• | Inspect the brake components at all wheels. |
• | Verify no brake drag exists after brake switch adjustment. |
• | Verify even brake application with no pull or lead. |
• | Inspect for worn/damaged brake pads. |
• | Inspect for worn/damaged wheel bearings. |
• | Inspect the wheel speed sensor/wiring. |
• | Inspect the exciter rings for damage. |
• | Inspect the tires for tread depth/wear. |
• | Road test the vehicle to verify the complaint. |
Step | Action | Yes | No | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
1 |
Does the scan tool communicate with the EBCM? | Go to Step 2 | Go to Step 4 | ||||||||
2 | Where any DTCs stored current or history? | Go to Step 3 | Go to Step 6 | ||||||||
3 |
Were any DTCs stored? | Go to Step 6 | |||||||||
4 | Does the scan tool communicate with other modules on the data line? | Go to Step 5 | |||||||||
5 |
Did you complete the repair? | System OK | -- | ||||||||
6 |
Did the ABS warning lamp and brake warning lamp turn ON for 3 seconds and then turn OFF bulb test? | System OK |