Dodge Ram Truck 1500-2500-3500. Manual — part 52

C144B-REAR DIFFERENTIAL RETURN CIRCUIT HIGH (CONTINUED)

3.

(T528) REAR LOCKER RETURN CIRCUIT SHORTED TO BATTERY VOLTAGE

Turn the ignition off.

Disconnect the FDCM harness connector.

Turn the ignition on.

Measure the voltage of the (T528) Rear Locker Return circuit at the
FDCM harness connector.

Does the voltmeter indicate voltage present?

Yes

>> Repair the short to voltage in the (T528) Rear Locker

Return circuit.

Perform FDCM VERIFICATION TEST.

No

>> Go To 4

4.

(T528) REAR LOCKER RETURN CIRCUIT SHORTED TO (T526) REAR LOCKER SOURCE CIRCUIT

Turn the ignition off.

Measure the resistance between the (T526) Rear Locker Source cir-
cuit and the (T528) Rear Locker Return circuit in the Rear Locker
Solenoid harness connector.

Is the resistance below 100 ohms?

Yes

>> Repair the short between (T526) Rear Locker Source cir-

cuit and the (T528) Rear Locker Return circuit.

Perform FDCM VERIFICATION TEST

No

>> Go To 5

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DIFFERENTIAL & DRIVELINE - ELECTRICAL DIAGNOSTICS

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C144B-REAR DIFFERENTIAL RETURN CIRCUIT HIGH (CONTINUED)

5.

FDCM

NOTE: Before continuing, check the FDCM harness connector terminals for corrosion, damage, or terminal
push out. Repair as necessary.
Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and
Ground circuits.

Were there any problems found?

Yes

>> Repair as necessary.

Perform FDCM VERIFICATION TEST

No

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

Perform FDCM VERIFICATION TEST.

6.

INTERMITTENT WIRING AND CONNECTORS

The conditions necessary to set this DTC are not present at this time.

Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.

Wiggle test the wiring harness and connectors while checking for shorted and open circuits.

Using the DRBIII

T

, monitor the data related to this circuit while performing the wiggle test. Look for the data to

change or for the DTC to reset.

Were there any problems found?

Yes

>> Repair as necessary.

Perform FDCM VERIFICATION TEST.

No

>> Test Complete.

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DIFFERENTIAL & DRIVELINE - ELECTRICAL DIAGNOSTICS

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C144E-FRONT DIFFERENTIAL POSITION SENSOR PERFORMANCE

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DIFFERENTIAL & DRIVELINE - ELECTRICAL DIAGNOSTICS

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C144E-FRONT DIFFERENTIAL POSITION SENSOR PERFORMANCE (CONTINUED)

For a complete wiring diagram Refer to Section 8W.

•

When Monitored:
The ignition on. Axle Locker Switch in the FR/RR position.

•

Set Condition:
The FDCM detects that the Front Differential Position Sensor is in an unexpected state.

Possible Causes

(T522) FRONT DIFFERENTIAL POSITION SENSOR (WIRING, CONNECTOR AND/OR TERMINAL CONDITION)

FRONT DIFFERENTIAL POSITION SENSOR

(T522) FRONT LOCKER SENSOR SENSE OPEN

FDCM

Diagnostic Test

1.

ACTIVE DTC

CAUTION: Before removing the FDCM harness connector, clean the connector and locking cam area of dirt
and debris. Failure to do so can result in the connector being jammed or damage to the locking cams on
the harness connector or module. Do not force the assist arm when releasing or installing the harness con-
nector.
Ignition on, engine not running.

With the DRBIII

T

, read DTCs.

Is the DTC active at this time?

Yes

>> Go To 2

No

>> Go To 6

2.

FRONT DIFFERENTIAL POSITION SENSOR WIRING

NOTE: Before continuing with the below diagnostic test, ensure the FDCM harness connector seal is
installed correctly. Inspect the terminals on both harness connector and the module for damage. Failure to
do so can result in misdiagnoses of the system.
Using the DRBIII

T

, actuate the Front Locker Solenoid.

Monitor the Front Differential Position Sensor State.

Wiggle the related wiring harness from the FDCM to the Front Locker Solenoid connector at the axle.

With a DRBIII

T

, actuate the Front Locker Solenoid.

Does the state on the DRBIII

T

change while wiggling the wiring harness?

Yes

>> Using the schematics as a guide, inspect the wiring and connectors specific to this circuit. Check the

Locker Solenoid terminals and connectors for corrosion and/or dirty that may compromise the connec-
tion. Repair as necessary.

Perform FDCM VERIFICATION TEST.

No

>> Go To 3

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