No Response From Controller Anti-lock Brake

Possible Causes:

No response from CAB
Ground Circuit Open
Open Fused Ignition Switch Output Circuit
Open PCI Bus Circuit
Controller Anti-lock Brake

Testing

NOTE: As soon as one or more module communicates with the DRBIII(R), answer the question.

Turn the ignition on. With the DRBIII(R), attempt to communicate with the Airbag Control Module (ACM) and 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, refer to COMMUNICATIONS and perform the symptom NO RESPONSE FROM PCM (PCI BUS). See SYMPTOM IDENTIFICATION table. Perform ABS VERIFICATION TEST .
Turn the ignition off. Disconnect the CAB harness connector. Using a 12-volt test light connected to 12-volts, probe both ground circuits. Is the test light illuminated for both circuits? If yes, go to next step. If no, repair the ground circuits for an open. Perform ABS VERIFICATION TEST .
Turn the ignition off. Disconnect the CAB harness connector. Turn the 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 .

NOTE: Ensure there is PCI Bus communication with other modules on the vehicle before proceeding. If not, diagnose and repair Communication problem as necessary. See COMMUNICATIONS in DIAGNOSTIC TROUBLE CODE IDENTIFICATION and SYMPTOM IDENTIFICATION table.

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. With the DRBIII(R) select Pep Module Tools. Select lab scope. Select Live Data. Select 12 volt square ware. 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 the 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 .
If there are no possible causes remaining, replace the Controller Anti-lock Brake (CAB). See CONTROLLER ANTI-LOCK BRAKE (CAB) . Perform ABS VERIFICATION TEST .