Diagnostic Test

WARNING: This page is about a different car, the 2015 RAM 3500 HD and 2015 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.

VERIFY THE ACTIVE DTC
1. Ignition on, engine not running.
2. With the scan tool, record and erase DTCs.
3. With the scan tool, read DTCs.
  Is the DTC active at this time?
  
  Yes
  - Go To 2
  No
  - Go To 12
(F946) FUSED IGNITION RUN/START CONTROL OUTPUT CIRCUIT OPEN OR HIGH RESISTANCE
1. Turn the ignition off to the lock position.
2. Disconnect the FAD Module harness connector.
3. Disconnect the DTCM C1 harness connector.
4. Ignition on, engine not running.
5. Using a 12-volt test light connected to ground, check the (F946) Fused Ignition Run/Start Control Output circuit at the FAD Module harness connector and the DTCM C1 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 3
  No
  - Repair the (F946) Fused Ignition Run/Start Control Output circuit for an open or high resistance. Inspect the related fuse. If the fuse is open, check the circuit for a short to ground.
  - Perform the DTCM VERIFICATION TEST. Refer to STANDARD PROCEDURE .
(G303) FRONT AXLE LOCK SIGNAL CIRCUIT SHORTED TO VOLTAGE
1. Measure the voltage between ground and the (G303) Front Axle Lock Signal circuit at the DTCM harness connector.
  Is any there voltage present?
  
  Yes
  - Repair the (G304) Front Axle Lock Control circuit for a short to voltage.
  - Perform the DTCM VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 4
(G303) FRONT AXLE LOCK SIGNAL CIRCUIT SHORTED TO GROUND
1. Turn the ignition off to the lock position.
2. Measure the resistance between ground and the (G303) Front Axle Lock Signal Control circuit at the DTCM harness connector.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Repair the (G303) Front Axle Lock Signal circuit for a short to ground.
  - Perform the DTCM VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 5
(G303) FRONT AXLE LOCK SIGNAL CIRCUIT OPEN
1. Measure the resistance of the (G303) Front Axle Lock Signal circuit between the DTCM harness connector and the FAD Module harness connector.
  Is the resistance above 5.0 Ohms?
  
  Yes
  - Repair the (G303) Front Axle Lock Signal circuit for an open or high resistance.
  - Perform the DTCM VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 6
(G304) FRONT AXLE LOCK CONTROL CIRCUIT OPEN
1. Measure the resistance of the (G304) Front Axle Lock Control circuit between the DTCM harness connector and the FAD Module harness connector.
  Is the resistance above 5.0 Ohms?
  
  Yes
  - Repair the (G304) Front Axle Lock Control circuit for an open or high resistance.
  - Perform the DTCM VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 7
(G304) FRONT AXLE LOCK CONTROL CIRCUIT SHORTED TO VOLTAGE
1. Measure the voltage between ground and the (G304) Front Axle Lock Control circuit at the DTCM harness connector.
  Is any there voltage present?
  
  Yes
  - Repair the (G304) Front Axle Lock Control circuit for a short to voltage.
  - Perform the DTCM VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 8
(G304) FRONT AXLE LOCK CONTROL CIRCUIT SHORTED TO GROUND
1. Turn the ignition off to the lock position.
2. Measure the resistance between ground and the (G304) Front Axle Lock Control circuit at the DTCM harness connector.
  Is the resistance below 5.0 Ohms?
  
  Yes
  - Repair the (G304) Front Axle Lock Control circuit for a short to ground.
  - Perform the DTCM VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 9
(Z908) GROUND CIRCUIT OPEN
1. Measure the resistance of the (Z908) Ground circuit between the DTCM harness connector and the FAD Module harness connector.
  Is the resistance above 5.0 Ohms?
  
  Yes
  - Repair the (Z908) Ground circuit for an open or high resistance.
  - Perform the DTCM VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 10
(Z908) GROUND CIRCUIT SHORTED TO VOLTAGE
1. Measure the voltage between ground and the (Z908) Ground circuit at the DTCM harness connector.
  Is any there voltage present?
  
  Yes
  - Repair the (Z908) Ground circuit for a short to voltage.
  - Perform the DTCM VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Go To 11
FRONT AXLE DISCONNECT (FAD) MODULE
1. Replace the Drive Train Control Module (DTCM) in accordance with the Service Information. Refer to MODULE, DRIVETRAIN CONTROL, REMOVAL .
2. Ignition on, engine not running.
3. With the scan tool, read DTCs.
  Does the DTC remain active?
  
  Yes
  - Replace the Front Axle Disconnect (FAD) Module.
  - Perform the DTCM VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Test Complete.
INTERMITTENT CONDITION AND WIRING HARNESS PROCEDURE
1. The conditions necessary to set this DTC are not present at this time.
2. Using the wiring diagram/schematic as a guide, inspect the wiring harness and connectors for corrosion, water intrusion, proper pin tension and bent or broken pins/terminal ends.
3. Wiggle test the wiring harness and connectors while monitoring the scan tool data relative to this circuit.
4. Look for the data to change or for the DTC to reset during the wiggle test.
5. While monitoring the scan tool data relative to this circuit, move the selector switch to each position several times.
6. Look for the data to change other than as expected or for the DTC to reset.
  Were there any problems found?
  
  Yes
  - Repair as necessary.
  - Perform the DTCM VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  No
  - Test Complete.