Diagnostic Test

WARNING: This page is about a different car, the 2019 RAM 3500 HD and 2019 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.

CHECK FOR ACTIVE DTC
1. Ignition on, engine not running.
2. With the scan tool, read DTCs.
  Is the DTC Active?
  
  Yes
  - Go To 2
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
CHECK FOR OTHER DTCS
NOTE:
Repair any Voltage Low DTCs before proceeding with this test procedure.

NOTE:
The J1939 Datalink is a BUS circuit which the PCM uses to communicate with the DEF Quality Sensor, Turbo Actuator, DEF Dosing Control Unit, NOx Sensor 1/1, NOx Sensor 1/2, and Particulate Matter Sensor (if equipped). The Turbo Actuator and NOx Sensor 1/1 are located on their own network in the engine harness. The DEF Quality Sensor, DEF Dosing Control Unit, NOx Sensor 1/2, and Particulate Matter Sensor (if equipped) are located on a separate network in the vehicle harness. If the J1939 Datalink in the engine harness is shorted, communication lost DTC's will be set against the Turbo Actuator and NOx Sensor 1/1. If the J1939 Datalink in the vehicle harness is shorted, communication lost DTCs will be set against the DEF Quality Sensor, DEF Dosing Control Unit, NOx Sensor 1/2, and Particulate Matter Sensor (if equipped). The DEF Quality Sensor, NOx Sensor 1/1, NOx Sensor 1/2, and Particulate Matter Sensor (if equipped) share the same fused battery supply circuit in the PDC. All these sensors will lose communication and set DTCs if the fuse is blown. The Turbo Actuator and the DEF Dosing Control Unit have their own separate fused battery circuits in the PDC.

Are there lost communication DTCs present against ALL the components in the vehicle harness (DEF Quality Sensor, NOx Sensor 1/2, DEF Dosing Control Unit)?

Yes
- Go To 8
No
- Go To 3
CHECK THE DEF DCU CONNECTOR FOR CORROSION OR FOREIGN MATERIAL
1. Turn the ignition on.
2. With the scan tool, record all Freeze frame data.
3. With the scan tool, erase DTCs.
4. Disconnect the DEF Dosing Control Unit C1 harness connector.
  NOTE:
  Check connectors for corrosion or foreign materials- Clean/repair as necessary.
5. Reconnect the DEF Dosing Control Unit C1 harness connector.
6. Test drive the vehicle for an extended amount of time.
  Did the DTC return?
  
  Yes
  - Go To 4
  No
  - Repair is complete.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE (A969) FUSED BATTERY SUPPLY CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Turn the ignition off.
2. Disconnect the DEF Dosing Control Unit C1 harness connector.
  NOTE:
  Check connectors - Clean/repair as necessary.
3. Measure the voltage of the (A969) Fused Battery Supply circuit at the DEF Dosing Control Unit C1 harness connector.
  NOTE:
  Check the voltage at key-on and during engine cranking.
  
  Is the voltage within 1.0 volt of battery voltage?
  
  Yes
  - Go To 5
  No
  - Using the appropriate wiring diagram as a guide, repair the (A969) Fused Battery Supply circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE (K970) DCU WAKE-UP SIGNAL CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Turn the ignition off.
2. Measure the voltage of the (K970) DCU Wake-up Signal circuit at the DEF Dosing Control Unit C1 harness connector.
  NOTE:
  Check the voltage at key-on and during engine cranking.
  
  Is the voltage within 1.0 volt of battery voltage?
  
  Yes
  - Go To 6
  No
  - Using the appropriate wiring diagram as a guide, repair the (K970) DCU Wake-up Signal circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE (Z914) DEF DOSING CONTROL UNIT GROUND CIRCUIT FOR AN OPEN/HIGH RESISTANCE
1. Turn the ignition off.
2. Measure the resistance between ground and the (Z914) DEF Dosing Control Ground circuits at the DEF Dosing Control Unit C1 harness connector.
  Is the resistance below 5.0 Ohms for the ground circuit?
  
  Yes
  - Go To 7
  No
  - Using the appropriate wiring diagram as a guide, repair the (Z914) DEF Dosing Control Unit Ground circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE J1939 DATALINK CIRCUITS FOR AN OPEN/HIGH RESISTANCE
1. Disconnect the NOx Sensor Module 1/2 harness connector.
2. Disconnect the DEF Quality Sensor Module C1 harness connector.
3. Disconnect the PCM C2 harness connector.
  NOTE:
  Check connectors - Clean/repair as necessary.
4. Measure the resistance of the (D134) J1939 Datalink (+) circuit between the DEF Dosing Control Unit C1 harness connector and the PCM C2 harness connector.
5. Measure the resistance of the (D135) J1939 Datalink (-) circuit between the DEF Dosing Control Unit C1 harness connector and the PCM C2 harness connector.
  Is the resistance below 5.0 Ohms for both circuits?
  
  Yes
  - Replace the DEF Dosing Control Unit in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Repair the J1939 circuit that measured above 5.0 Ohms for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE COMPONENTS ON THE J1939 DATALINK
NOTE:
Disconnect only one component at a time during this next step. If the DTCs for the components that are STILL CONNECTED change from active to stored, the component that was disconnected is faulty. If all of the DTCs remain active, then the disconnected component is not the problem. Reconnect each component before going on to the next one so that only one component is disconnected at a time.
1. Turn the ignition off.
2. Disconnect the DEF Dosing Unit C1 Connector. Cycle the ignition key on and off 3 times ending with the ignition on. Leave the ignition in the off position for 75 seconds each time.
  NOTE:
  Monitor the status of the DTCs for the remaining connected components with the scan tool.
3. Turn the ignition off and reconnect the DEF Dosing Unit C1 Connector.
4. Disconnect the NOx Sensor Module 1/2 harness connector. Cycle the ignition key on and off 3 times ending with the ignition on. Leave the ignition in the off position for 75 seconds each time.
  NOTE:
  Monitor the status of the DTCs for the remaining connected components with the scan tool.
5. Turn the ignition off and reconnect the NOx Sensor Module 1/2 harness connector.
6. Disconnect the DEF Quality Sensor C1 harness connector. Cycle the ignition key on and off 3 times ending with the ignition on. Leave the ignition in the off position for 75 seconds each time.
  NOTE:
  Monitor the status of the DTCs for the remaining connected components with the scan tool.
7. Turn the ignition off and reconnect the DEF Quality Sensor C1 harness connector.
  Did the status of the DTCs change to stored for the components STILL CONNECTED when disconnecting any one of the components listed above?
  
  Yes
  - Replace the component that caused the DTC change from active to stored in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 9
CHECK THE J1939 DATALINK CIRCUITS FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Disconnect the NOx Sensor Module 1/2, DEF Dosing Control Unit C1, DEF Quality Sensor C1, and the PCM C2 harness connectors.
3. Measure the resistance between ground and the (D134) J1939 Datalink (+) circuit at the PCM C2 harness connector.
4. Measure the resistance between ground and the (D135) J1939 Datalink (-) circuit at the PCM C2 harness connector.
  Is the resistance above 10k Ohms for both circuits?
  
  Yes
  - Go To 10
  No
  - Repair the J1939 circuit that measured below 10k Ohms for a short to ground.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE J1939 DATALINK CIRCUITS FOR A SHORT
1. Measure the resistance between the (D134) J1939 Datalink (+) circuit at the PCM C2 harness connector and all other circuits in the PCM C2 harness connector.
2. Measure the resistance between the (D135) J1939 Datalink (-) circuit at the PCM C2 harness connector and all other circuits in the PCM C2 harness connector.
  NOTE:
  Disregard any resistance between 50 and 70 Ohms between the J1939 (+) and the J1939 Datalink (-) pins.
  
  Is the resistance above 10k Ohms for both measurements?
  
  Yes
  - Go To 11
  No
  - Repair the J1939 circuit for a short circuit.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE J1939 DATALINK CIRCUITS FOR AN OPEN/HIGH RESISTANCE
1. Measure the resistance of the (D134) J1939 Datalink (+) circuit between the DEF Dosing Control Unit C1 harness connector and the PCM C2 harness connector.
2. Measure the resistance of the (D135) J1939 Datalink (-) circuit between the DEF Dosing Control Unit C1 harness connector and the PCM C2 harness connector.
  Is the resistance below 5.0 Ohms for both circuits?
  
  Yes
  - Go To 12
  No
  - Repair the J1939 circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
POWERTRAIN CONTROL MODULE
1. Disconnect all PCM harness connectors.
2. Disconnect all related in-line harness connections (if equipped).
3. Disconnect the related component harness connectors.
4. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
  - Proper connector installation.
  - Damaged connector locks.
  - Corrosion.
  - Other signs of water intrusion.
  - Weather seal damage (if equipped).
  - Bent terminals.
  - Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
  - Terminals that have been pushed back into the connector cavity.
  - Perform a terminal drag test on each connector terminal to verify proper terminal tension.
  Repair any conditions that are found.
5. Reconnect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
6. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
7. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
8. With the scan tool, erase DTCs.
9. Using the recorded Freeze Frame and Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
10. With the scan tool, read PCM DTCs.
  Did the DTC return?
  
  Yes
  - Replace the Powertrain Control Module (PCM) in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Test complete.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .