No Response From Controller Antilock Brake

Possible Causes are:

• NO RESPONSE FROM CAB
• REPLACE FUSE No. 19
• CONTROLLER ANTILOCK BRAKE SHORTED TO GROUND
• FUSED IGNITION SWITCH OUTPUT CIRCUIT SHORTED TO GROUND
• JUNCTION BLOCK SHORTED TO GROUND
• GROUND CIRCUIT OPEN
• OPEN FUSED IGNITION SWITCH OUTPUT CIRCUIT
• OPEN PCI BUS CIRCUIT
• CONTROLLER ANTILOCK BRAKE

1. Turn ignition on. As soon as one or more module communicates Using the DRBIII(R), answer the question. Using the DRBIII(R), attempt to communicate with the Airbag Control Module (ACM) and the Body Control Module (BCM). Was the DRBIII(R) able to I.D. or establish communications with either of the modules? If yes, go to next step. If no, diagnose using appropriate procedure. See COMMUNICATION  under DIAGNOSTIC TESTS. Perform ABS VERIFICATION TEST VER 1  under VERIFICATION TESTS.
2. Turn ignition off. Remove and inspect fuse No. 19 in the junction block. Is the fuse open? If yes, go to next step. If no, go to step  6 .
3. Turn ignition off. Replace Fuse No. 19 in the junction block. Turn ignition on. Remove and inspect fuse No. 19 in the junction block. Is the fuse open? If yes, go to next step. If no, check the Fused Ignition Switch Output circuit for an intermittent short to ground. See WIRING DIAGRAMS  . Perform ABS VERIFICATION TEST VER 1  under VERIFICATION TESTS.
4. Turn ignition off. Replace fuse No. 19 in the junction block. Disconnect the CAB harness connector. Turn ignition on. Remove and inspect fuse No. 19 in the junction block. Is the fuse open? If yes, go to next step. If no, replace the Controller Antilock Brake. Perform ABS VERIFICATION TEST VER 1  under VERIFICATION TESTS.
5. Turn ignition off. Disconnect the CAB harness connector. Disconnect the Junction Block C2 harness connector. Measure the resistance between ground and the Fused Ignition Switch Output circuit. Is the resistance less than 5 ohms? If yes, repair the Fused Ignition Switch Output circuit for a short to ground. Perform ABS VERIFICATION TEST VER 1  under VERIFICATION TESTS. If no, replace the junction block. Perform ABS VERIFICATION TEST VER 1  under VERIFICATION TESTS.
6. Turn ignition off. Disconnect the CAB harness connector. Using a 12-volt test light connected to 12 volts, probe each ground circuit. Is the test light illuminated for each circuit? If yes, go to next step. If no, repair the ground circuit(s) for an open. Perform ABS VERIFICATION TEST VER 1  under VERIFICATION TESTS.
7. Turn ignition off. Ensure fuse No. 19 is installed in the junction block. Disconnect the CAB harness connector. Turn ignition on. Using a 12-volt test light connected to ground, probe the Fused Ignition Switch Output circuit. Is the test light illuminated? If yes, go to next step. If no, repair the Fused Ignition Switch Output circuit for an open. Perform ABS VERIFICATION TEST VER 1  under VERIFICATION TESTS.
8. Disconnect the CAB harness connector. Use Scope Input Cable (CH7058), Cable To Probe Adapter (CH7062), and the Red and Black test probes. Connect the scope input cable to the channel one connector on the DRBIII(R). Attach the Red and Black leads and the cable to probe adapter to the scope input cable. Using the DRBIII(R), select Pep Module Tools. Select lab scope. Select Live Data. Select 12-volt square wave. Press F2 for Scope. Press F2 and use the down arrow to set voltage range to 20 volts. Set Probe to x10. Press F2 again, when complete. Connect the Black lead to the chassis ground. Connect the Red lead to the PCI Bus circuit in the CAB connector. Turn ignition on. Observe the voltage display on the DRBIII(R) Lab Scope. Does the voltage pulse from 0 to approximately 7.5 volts? If yes, go to next step. If no, repair the PCI Bus circuit for an open. Perform ABS VERIFICATION TEST VER 1  under VERIFICATION TESTS.
9. If there are no possible causes remaining, replace the Controller Antilock Brake. Perform ABS VERIFICATION TEST VER 1  under VERIFICATION TESTS.