No Response From HFM (Hands Free Module)
NO RESPONSE FROM HANDS FREE MODULENo Response From Hands Free Module:
POSSIBLE CAUSES
- (Z970) Ground circuit open
- (A114) Fused B+ circuit open
- (F983) Fused ignition switch output circuit open
- (D25) PCI BUS circuit open
- Hands free module
Diagnostic Test
1. ESTABLISH COMMUNICATIONS WITH THE INSTRUMENT CLUSTER (MIC)
Turn the ignition on.
NOTE: 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 MIC.
Q: Was the DRB able to I/D or communicate with the MIC?
YES: Go To 2
NO: Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
2. (Z970) GROUND CIRCUIT OPEN
Turn the ignition off.
Disconnect the Hands Free Module C1 harness connector.
Using a 12-volt test light connected to 12-volts, probe the (Z970) ground circuit.
Q: Is the test light illuminated?
YES: Go To 3
NO: Repair the (Z970) Ground circuit for an open. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
3. (A114) FUSED B+ CIRCUIT OPEN
Using a 12-volt test light connected to ground, probe the (A114) Fused B+ circuit.
Q: Is the test light illuminated?
YES: Go To 4
NO: Repair the (A114) Fused B+ circuit for an open. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
4. (F983) FUSED IGNITION SWITCH OUTPUT CIRCUIT OPEN
Turn the ignition on.
Using a 12-volt test light connected to ground, probe the (F983) Fused Ignition Switch Output circuit.
Q: Is the test light illuminated?
YES: Go To 5
NO: Repair the (F983) Fused Ignition Switch Output circuit for an open. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
5. (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 HFM 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 Hands Free Module. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Repair the (D25) PCI Bus circuit for an open. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test