No Response From ABS (Antilock Brake Module)

NO RESPONSE FROM ANTILOCK BRAKE MODULE

No Response From Antilock Brake Module:

POSSIBLE CAUSES
- (Z107) (Z127) Ground circuit open
- (F500) Fused ignition switch output circuit open
- (D25) PCI BUS circuit open
- Antilock brake module

Diagnostic Test

1. ESTABLISH COMMUNICATIONS WITH OTHER PCI BUS MODULES
Turn the ignition on.

NOTE:
- As soon as one or more modules communicates with the DRB, answer the question.
- Ensure there is PCI bus communication with other modules. If not, refer to the PCI Bus Communication Failure symptom and repair as necessary.

With the DRB, attempt to communicate with the ORC.
With the DRB, attempt to communicate with the Instrument Cluster.

Q: Was the DRB able to I/D or communicate with either of the modules?

YES: Go To 2
NO: Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test

2. (Z107) (Z127) GROUND CIRCUIT OPEN




Turn the ignition off.
Disconnect the Antilock Brake Module C1 harness connector.
Using a 12-volt test light connected to 12-volts, probe each (Z107) (Z127, if equipped) ground circuit.

Q: Is the test light illuminated for each circuit?

YES: Go To 3
NO: Repair the (Z107) or (Z127) Ground circuit for an open. Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test

3. (F500) FUSED IGNITION SWITCH OUTPUT CIRCUIT OPEN




Turn the ignition on.
Using a 12-volt test light connected to ground, probe the (F500) Fused Ignition Switch Output circuit.

Q: Is the test light illuminated?

YES: Go To 4
NO: Repair the (F500) Fused Ignition Switch Output circuit for an open. Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test

4. (D25) PCI BUS CIRCUIT OPEN




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 DRB.
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 wave.
Press F2 for Scope.
Press F2 and use the down arrow to set voltage range to 20 volts.
Press F2 again when complete.
Connect the Black lead to the chassis ground.
Connect the Red lead to the PCI Bus circuit in the Antilock Brake Module connector.
Observe the voltage display on the DRB Lab Scope.

Q: Does the voltage pulse from 0 to approximately 7.5 volts?

YES: Replace the Antilock Brake Module. Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test
NO: Repair the (D25) PCI Bus circuit for an open. Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test