Final Drive Control Module

C2100-BATTERY VOLTAGE LOW (FDCM)

For a complete wiring diagram refer to diagrams.
^ When Monitored:
Continuously.
^ Set Condition:
The Final Drive Control Module detects that system voltage is below 9.0 volts for 60 seconds.

Possible Causes

- INTERMITTENT BATTERY VOLTAGE LOW
- CHARGING SYSTEM DTCS PRESENT
- FINAL DRIVE CONTROL MODULE POWER CIRCUITS OPEN OR HIGH RESISTANCE
- FINAL DRIVE CONTROL MODULE

Diagnostic Test

1. CHARGING SYSTEM DTCS PRESENT
Ignition on.
With the scan tool, select View DTCs in the Powertrain Control Module.

Are there any Charging System or related voltage DTCs present?
Yes >>Refer to the symptom list and perform any Charging System DTC diagnostic procedures before continuing with this test.
No >>Go to 2

2. DTC IS ACTIVE
With the scan tool, select View DTCs in the Final Drive Control Module.

Is the status Active for this DTC?
Yes >>Go to 3
No >>Go to 5

3. (A34) FUSED B+ CIRCUIT OPEN OR HIGH RESISTANCE





Turn the ignition off.
Disconnect the Final Drive Control Module harness connector.
Turn the ignition on.
With a 12-volt test light connected to ground, check the (A34) Fused B+ circuit in the Final Drive Control Module harness connector.

NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.

Does the test light illuminate brightly?
Yes >>Go to 4
No >>Repair the (A34) Fused B+ circuit for an open circuit or high resistance.
Perform the FDCM VERIFICATION TEST.
4. FINAL DRIVE CONTROL MODULE
View repair.

Repair
Replace the Final Drive Control Module in accordance with the Service information.
Perform the FDCM VERIFICATION TEST.
5. INTERMITTENT WIRING AND CONNECTORS
The conditions necessary to set this DTC are not present at this time.
Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
While monitoring the scan tool data relative to this circuit, wiggle test the wiring and connectors.
Look for the data to change or for the DTC to reset during the wiggle test.

Were any problems found?
Yes >>Repair as necessary.
Perform the FDCM VERIFICATION TEST.
No >>Test complete.