Dodge Ram Truck 1500-2500-3500. Manual — part 1841

C1400-TRANSFER CASE RANGE SELECT SWITCH PERFORMANCE

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TRANSFER CASE - ELECTRICAL DIAGNOSTICS (POWER WAGON)

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C1400-TRANSFER CASE RANGE SELECT SWITCH PERFORMANCE (CONTINUED)

For a complete wiring diagram Refer to Section 8W

•

When Monitored:
With the ignition on and no system undervoltage or overvoltage condition present.

•

Set Condition:
The Final Drive Control Module is not receiving a valid voltage for any switch position.

Possible Causes

INTERMITTENT TRANSFER CASE RANGE SELECT SWITCH PERFORMANCE

(K77) TRANSFER CASE POSITION SENSE CIRCUIT OPEN

(K77) TRANSFER CASE POSITION SENSE CIRCUIT SHORTED TO GROUND

(T525) TRANSFER CASE RETURN CIRCUIT OPEN

(T525) TRANSFER CASE RETURN CIRCUIT SHORT TO GROUND

TRANSFER CASE POSITION SENSOR

FINAL DRIVE CONTROL MODULE

Diagnostic Test

1.

DTC IS ACTIVE

Ignition on, engine not running.

NOTE: Repair any system undervoltage or overvoltage DTCs that are set in this module before proceeding.
With the scan tool, select View DTCs in the Final Drive Control Module.

Is the status Active for this DTC?

Yes

>> Go To 2

No

>> Go To 9

2.

(K77) TRANSFER CASE POSITION SENSE CIRCUIT VOLTAGE

Turn the ignition off.

Disconnect the Transfer Case Position Sensor harness connector.

Turn the ignition on.

Measure the voltage of the (K77) Transfer Case Position Sense circuit.

Is the voltage between 4.7 and 5.2 volts?

Yes

>> Go To 5

No

>> Go To 3

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C1400-TRANSFER CASE RANGE SELECT SWITCH PERFORMANCE (CONTINUED)

3.

(K77) TRANSFER CASE POSITION SENSE CIRCUIT OPEN

Turn the ignition off.

Disconnect the Final Drive Control Module harness connector.

Measure the resistance of the (K77) Transfer Case Position Sense cir-
cuit.

Is the resistance greater than 5.0 ohms?

Yes

>> Repair the (K77) Transfer Case Position Sense circuit for

an open.

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

No

>> Go To 4

4.

(K77) TRANSFER CASE POSITION SENSE CIRCUIT SHORTED TO GROUND

Measure the resistance between the (K77) Transfer Case Position
Sense circuit and ground.

Is the resistance less than 5.0 ohms?

Yes

>> Repair the (K77) Transfer Case Position Sense circuit for

a short to ground. (Refer to 3 - DIFFERENTIAL & DRIV-
ELINE - DIAGNOSIS AND TESTING)

Perform the FDCM VERIFICATION TEST.

No

>> Go To 8

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TRANSFER CASE - ELECTRICAL DIAGNOSTICS (POWER WAGON)

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C1400-TRANSFER CASE RANGE SELECT SWITCH PERFORMANCE (CONTINUED)

5.

TRANSFER CASE POSITION SENSOR

Ignition on, engine not running.

With the scan tool in Data Display, read the 4wd Range Switch Volt-
age with the Transfer Case Position Sensor harness connector discon-
nected.

The switch voltage should be approximately 0 volts.

Turn the ignition off.

Connect a jumper wire between the (K77) Transfer Case Position
Sense circuit and the (T525) Transfer Case Return circuit in the Trans-
fer Case Position Sensor harness connector.

Ignition on, engine not running.

With the scan tool in Data Display, read the 4wd Range Switch Volt-
age.

The switch voltage should be approximately 5 volts.

Does the voltage display as described?

Yes

>> Replace the Transfer Case Position Sensor.

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

No

>> Go To 6

6.

(T525) TRANSFER CASE RETURN CIRCUIT OPEN

Turn the ignition off.

Disconnect the Final Drive Control Module harness connector.

Measure the resistance of the (T525) Transfer Case Return circuit
between the Transfer Case Position Sensor harness connector and
the Final Drive Control Module harness connector.

Is the resistance above 5.0 ohms?

Yes

>> Repair the (T525) Transfer Case Return circuit for an

open.

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

No

>> Go To 7

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