Dodge Ram Truck 1500-2500-3500. Manual — part 306

C2100–BATTERY VOLTAGE LOW (FDCM) (CONTINUED)

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 bright-
ness 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. (Refer to 3 -
DIFFERENTIAL & DRIVELINE - DIAGNOSIS AND TEST-
ING)

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. (Refer to 3 - DIFFERENTIAL & DRIVELINE - DIAGNOSIS
AND TESTING)

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. (Refer to 3 - DIFFERENTIAL & DRIVELINE - DIAGNOSIS
AND TESTING)

No

>> Test complete.

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ELECTRONIC CONTROL MODULES - ELECTRICAL DIAGNOSTICS

DR/DH

C2101–BATTERY VOLTAGE HIGH (FDCM)

For a complete wiring diagram Refer to Section 8W

•

When Monitored:
Continuously.

•

Set Condition:
The Final Drive Control Module detects that system voltage is above 16.0 volts for 10 seconds with engine
RPM greater than 350.

Possible Causes

INTERMITTENT BATTERY VOLTAGE HIGH

CHARGING SYSTEM DTCS PRESENT

FINAL DRIVE CONTROL MODULE GROUND 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 con-

tinuing 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

DR/DH

ELECTRONIC CONTROL MODULES - ELECTRICAL DIAGNOSTICS

8E - 97

C2101–BATTERY VOLTAGE HIGH (FDCM) (CONTINUED)

3.

FINAL DRIVE CONTROL MODULE GROUND CIRCUITS 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 B+, check the Ground circuits in
the Final Drive Control Module harness connector.

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

Does the test light illuminate brightly for each of the Ground
circuits?

Yes

>> Go to 4

No

>> Repair the Ground circuit(s) for an open circuit or high

resistance.

Perform the FDCM VERIFICATION TEST. (Refer to 3 -
DIFFERENTIAL & DRIVELINE - DIAGNOSIS AND TEST-
ING)

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. (Refer to 3 - DIFFERENTIAL & DRIVELINE - DIAGNOSIS
AND TESTING)

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. (Refer to 3 - DIFFERENTIAL & DRIVELINE - DIAGNOSIS
AND TESTING)

No

>> Test complete.

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ELECTRONIC CONTROL MODULES - ELECTRICAL DIAGNOSTICS

DR/DH

C2201-FDCM ECU INTERNAL (FDCM)

For a complete wiring diagram Refer to Section 8W

•

When Monitored:
With the ignition on.

•

Set Condition:
The Final Drive Control Module has detected a failure internal to the controller.

Possible Causes

FINAL DRIVE CONTROL MODULE

1.

FINAL DRIVE CONTROL MODULE

The Final Drive Control Module has detected an internal failure.

View repair

Repair

Replace the Final Drive Control Module in accordance with the Service Information.

Perform the FDCM VERIFICATION TEST. (Refer to 3 - DIFFERENTIAL & DRIVELINE - DIAGNOSIS
AND TESTING)

DR/DH

ELECTRONIC CONTROL MODULES - ELECTRICAL DIAGNOSTICS

8E - 99