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Diagnostic Test

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NOTE:

The CAN C bus modules are connected in series. The Data Link Connector (DLC) is connected to the bus through the Body Control Module (BCM). The termination resistors for the CAN C bus are located in the BCM and Powertrain Control Module (PCM). Normal bus resistance is approximately 60 Ohms when both the BCM and PCM are connected. The bus resistance is approximately 120 Ohms when only the BCM or PCM is connected.

  1. CHECK THE CAN C BUS CIRCUITS FOR A SHORT TO VOLTAGE 
    1. Disconnect the scan tool.
    2. Turn the ignition on.
    3. Measure the voltage between ground and the CAN C Bus (+) circuit at the DLC.
    4. Measure the voltage between ground and the CAN C Bus (-) circuit at the DLC.

      Is either voltage above 10.0 volts?

      Yes 

      • Go To  2

      No 

      • Go To  3
  2. CHECK THE CAN C BUS CIRCUITS FOR A SHORT TO VOLTAGE IN THE HARNESS FROM THE DLC TO BCM 
    1. Turn the ignition off.
    2. Disconnect the BCM C3 harness connector.
    3. Turn the ignition on.
    4. Measure the voltage between ground and the CAN C Bus (+) circuit at the DLC.
    5. Measure the voltage between ground and the CAN C Bus (-) circuit at the DLC.

      Is any voltage present?

      Yes 

      • Repair the short to voltage in the CAN C Bus circuit.
      • Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .

      No 

      • Diagnose the short to voltage in the CAN C Bus circuit. The concern is located in one of the CAN C Bus circuits or modules between the BCM and the PCM. Starting with the PCM and working towards the BCM, use the module connectors to isolate portions of the bus to assist in determining the location of the concern. Repair as necessary. Only replace a module after all harness concerns are diagnosed.
      • Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  3. CHECK THE CAN C BUS CIRCUITS FOR A SHORT TO GROUND 
    1. Turn the ignition off.
    2. Disconnect and isolate the negative battery cable.
    3. Measure the resistance between ground and the CAN C Bus (+) circuit at the DLC.
    4. Measure the resistance between ground and the CAN C Bus (-) circuit at the DLC.

      Are the resistances above 5.0 Ohms?

      Yes 

      • Go To  5

      No 

      • Go To  4
  4. CHECK THE CAN C BUS CIRCUITS FOR A SHORT TO GROUND IN THE HARNESS FROM THE DLC TO BCM 
    1. Disconnect the BCM C3 harness connector.
    2. Measure the resistance between ground and the CAN C Bus (+) circuit at the DLC.
    3. Measure the resistance between ground and the CAN C Bus (-) circuit at the DLC.

      Are the resistances above 10k Ohms?

      Yes 

      • Diagnose the short to ground in the CAN C Bus circuit. The concern is located in one of the CAN C Bus circuits or modules between the BCM and the PCM. Starting with the PCM and working towards the BCM, use the module connectors to isolate portions of the bus to assist in determining the location of the concern. Repair as necessary. Only replace a module after all harness concerns are diagnosed.
      • Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .

      No 

      • Repair the short to ground in the CAN C Bus circuit.
      • Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  5. CHECK THE CAN C BUS CIRCUITS FOR A SHORT TOGETHER 
    Fig 1: Checking CAN C Bus Circuits For A Short Together
    GC0143419Courtesy of CHRYSLER GROUP, LLC
    1. Measure the resistance between the CAN C Bus (+) circuit and the CAN C Bus (-) circuit at the DLC.

      Is the resistance below 5.0 Ohms?

      Yes 

      • Go To  6

      No 

      • Go To  7
  6. CHECK THE CAN C BUS CIRCUITS FOR A SHORT TOGETHER IN THE HARNESS FROM THE DLC TO BCM 
    Fig 2: Checking CAN C Bus Circuits For A Short Together
    GC0143419Courtesy of CHRYSLER GROUP, LLC
    1. Disconnect the BCM C3 harness connector.
    2. Measure the resistance between the CAN C Bus (+) circuit and the CAN C Bus (-) circuit at the DLC.

      Is the resistance above 10k Ohms?

      Yes 

      • Diagnose the short between the CAN C Bus (+) circuit and the CAN C Bus (-). The concern is located in one of the CAN C Bus circuits or modules between the BCM and the PCM. Starting with the PCM and working towards the BCM, use the module connectors to isolate portions of the bus to assist in determining the location of the concern. Repair as necessary. Only replace a module after all harness concerns are diagnosed.
      • Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .

      No 

      • Repair the short between the CAN C Bus (+) circuit and the CAN C Bus (-).
      • Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  7. CHECK THE CAN C BUS CIRCUITS FOR AN OPEN IN THE HARNESS FROM THE DLC TO BCM 
    1. Disconnect the BCM C3 harness connector.
    2. Measure the resistance of the CAN C Bus (+) circuit between the DLC and the BCM C3 harness connector.
    3. Measure the resistance of the CAN C Bus (-) circuit between the DLC and the BCM C3 harness connector.

      Are the resistances below 5.0 Ohms?

      Yes 

      • Go To  8

      No 

      • Repair the open in the CAN C Bus circuit.
      • Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  8. CHECK FOR CORRECT BUS TERMINATION RESISTANCE 
    Fig 3: Checking For Correct BUS Termination Resistance
    GC0143419Courtesy of CHRYSLER GROUP, LLC
    1. Reconnect the BCM C3 harness connector.
    2. Measure the resistance between the CAN C Bus (+) circuit and the CAN C Bus (-) at the DLC.

      Is the resistance below 67 Ohms?

      Yes 

      • Test complete, the condition or conditions that originally set this DTC are not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.
      • Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .

      No 

      • For a resistance measurement of approximately 120 Ohms, Go To  9
      • For all others, repair the open or high resistance in the CAN C Bus (+) circuit or the CAN C Bus (-) circuit. The concern is located in one of the CAN C Bus circuits or modules between the BCM and the PCM. Starting with the PCM and working towards the BCM, use the module connectors to isolate portions of the bus to assist in determining the location of the concern. Repair as necessary. Only replace a module after all harness concerns are diagnosed.
      • Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  9. DETERMINE WHICH TERMINATION MODULE IS NOT CONNECTED TO THE CAN C BUS 
    Fig 4: Checking Which Termination Module Is Not Connected To The Can C Bus
    GC0143419Courtesy of CHRYSLER GROUP, LLC
    1. Disconnect the PCM harness connectors.
    2. Measure the resistance between the CAN C Bus (+) circuit and the CAN C Bus (-) at the DLC.

      Is the resistance approximately 120 Ohms?

      Yes 

      • The BCM is connected to the CAN C bus. The open is between the BCM and PCM. Use the module connectors to isolate portions of the bus to assist in determining the location of the concern. Repair as necessary. Only replace a module after all harness concerns are diagnosed.
      • Perform the BODY VERIFICATION TEST. Refer to STANDARD PROCEDURE .

      No 

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