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Home >> Dodge and Ram >> 2024 >> ProMaster 2500 Base >> Repair and Diagnosis >> External Pages >> Different car >> Section 16 (Body Control Module (BCM) - DTCS B1872-23 To U0254-86) >> DTC Troubleshooting >> U0010-00 Can BH Bus Mute >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different car, the 2024 RAM ProMaster EV. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK FOR AN ACTIVE DTC 
    NOTE:

    The CAN IHS Bus may also be known as the CAN B Bus or CAN BH Bus. 

    NOTE:

    If the scan tool will not communicate with the vehicle, proceed to SCAN TOOL DOES NOT COMMUNICATE WITH VEHICLE. Refer to  SCAN TOOL WILL NOT COMMUNICATE WITH VEHICLE  . 

    NOTE:

    Due to a loss of communication on the CAN Bus, multiple Electrical Control Units (ECUs) may not communicate on the network. If the scan tool communicates with the vehicle, but does not communicate with the Body Control Module (BCM), Go To Next Step. 

    1. Turn the ignition on.
    2. With the scan tool, read the BCM DTCs and record on the repair order.
    3. With the scan tool, erase the BCM DTCs.
    4. Turn the ignition off and wait 10 seconds.
    5. Turn the ignition on.
    6. With the scan tool, read the BCM DTCs.

      Did the DTC return?

      Yes 

      • Go To Next Step.

      No 

  2. CHECK THE (D101) CAN IHS BUS (+) AND THE (D102) CAN IHS BUS (-) CIRCUITS FOR A SHORT TO VOLTAGE 
    NOTE:

    Disconnecting the BCM may result in a loss of ignition status messages and may cause scan tool communication concerns. 

    NOTE:

    With a scan tool, refer to the network display to help identify ECUs that are unable to communicate with other ECUs on the CAN network. ECUs unable to communicate on the network will appear in red. 

    1. Make sure the ignition is on.
    2. Using the appropriate back-probe pins, back-probe and measure the voltage on the CAN IHS Bus (+) circuit at Security Gateway (SGW) Module harness connector.
    3. Using the appropriate back-probe pins, back-probe and measure the voltage on the CAN IHS Bus (-) circuit at SGW Module harness connector.

      Is the voltage above 5.0 volts on the CAN IHS Bus (+) or CAN IHS Bus (-) circuit?

      Yes 

      • Diagnose the short to voltage on the CAN IHS Bus (+) or CAN IHS Bus (-) circuit. Disconnecting Inline connectors and modules on the CAN IHS Bus can isolate portions of the CAN IHS Bus to assist in determining the location of the concern. Repair the shorted circuit or replace the module, that when disconnected, allows the CAN IHS Bus voltage to return to normal.
      • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .

      No 

      • Go To Next Step.
  3. CHECK THE (D101) CAN IHS BUS (+) AND THE (D102) CAN IHS BUS (-) CIRCUITS FOR A SHORT TO GROUND 
    1. Turn the ignition off.
    2. Disconnect and isolate the negative battery cable.
    3. If equipped with Engine Stop Start (ESS), disconnect and isolate the negative auxiliary battery cable.
    4. Using the appropriate back-probe pins, back-probe and check for continuity between ground and the CAN IHS Bus (+) circuit at SGW Module harness connector.
    5. Using the appropriate back-probe pins, back-probe and check for continuity between ground and the CAN IHS Bus (-) circuit at SGW Module harness connector.

      Is there continuity between ground and the CAN IHS Bus (+) or CAN IHS Bus (-) circuit?

      Yes 

      • Diagnose the short to ground on the CAN IHS Bus (+) or CAN IHS Bus (-) circuit. Disconnecting inline connectors and modules on the CAN IHS Bus can isolate portions of the bus to assist in determining the location of the concern. Repair the shorted circuit or replace the module, that when disconnected, allows the CAN IHS Bus voltage to return to normal.
      • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .

      No 

      • Go To Next Step.
  4. CHECK FOR CORRECT CAN IHS BUS TERMINATION RESISTANCE 
    NOTE:

    Total resistance of CAN networks must be measured with the battery disconnected. The average resistance is approximately 60 Ohms. The termination resistors are integral to the dominant modules. 

    NOTE:

    If resistances are higher than expected, inspect connectors for corrosion or poor terminal tension. 

    NOTE:

    The CAN IHS Bus Dominant Modules are the Body Control Module (BCM) and Instrument Panel Cluster (IPC). Refer to  COMMUNICATION, DESCRIPTION AND OPERATION  . 

    1. Disconnect the battery.
    2. Disconnect the SGW Module connector.
    3. Using the appropriate back-probe pins, back-probe and measure the resistance between the CAN IHS Bus (+) circuit and CAN IHS Bus (-) circuit at the SGW Module harness connector.

      If the resistance is approximately 60 Ohms (resistance is correct):

      • Go To  12.

      If the is resistance approximately 120 Ohms (resistance indicates an open or missing dominant module) :

      • Go To  10.

      If the resistance less than 55 Ohms (resistance indicates a shorted module or a short between the CAN IHS (+) and (-) circuits):

      • Go to  9.

      If the resistance is higher than 125 Ohms (resistance indicates an open circuit on the CAN IHS (+) and/or (-) circuits):

      Yes 

      • Go To  5.
  5. ISOLATE AND CHECK THE CAN IHS (+) CIRCUIT FOR AN OPEN TO BCM 
    1. Disconnect the related BCM connector.
    2. Measure the resistance on CAN IHS (+) circuit between the BCM connector and the SGW Module connector.

      Is the resistance over 3 Ohms?

      Yes 

      • Repair the open circuit, continue with Next Step.
      • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .

      No 

      • Go To Next Step.
  6. ISOLATE AND CHECK THE CAN IHS (-) CIRCUIT FOR AN OPEN TO BCM 
    1. Disconnect the related BCM connector.
    2. Measure the resistance on CAN IHS (-) circuit between the BCM connector and the SGW Module connector.

      Is the resistance over 3 Ohms?

      Yes 

      No 

      • Go to Next Step.
  7. ISOLATE AND CHECK THE CAN IHS (+) CIRCUIT FOR AN OPEN TO IPC 
    1. Disconnect the related IPC connector.
    2. Measure the resistance on CAN IHS (+) circuit between the IPC connector and the SGW Module connector.

      Is the resistance over 3 Ohms?

      Yes 

      • Repair the open circuit, continue with Next Step.
      • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .

      No 

      • Go To Next Step.
  8. ISOLATE AND CHECK THE CAN IHS (-) CIRCUIT FOR AN OPEN TO IPC 
    1. Disconnect the related IPC connector.
    2. Measure the resistance on CAN IHS (-) circuit between the IPC connector and the SGW Module connector.

      Is the resistance over 3 Ohms?

      Yes 

      No 

      • Go To the appropriate Diagnostic Information .
  9. ISOLATE THE SHORT BETWEEN THE CAN IHS (+) AND CAN IHS (-) 
    1. Using the appropriate back-probe pins, back-probe and measure the resistance between the CAN IHS Bus (+) circuit and CAN IHS Bus (-) circuit at the SGW Module harness connector.
    2. Continue to monitor the resistance at the SGW Module connector. Refer to Wiring diagrams and disconnect all of the CAN IHS modules connected to the SGW Module one at a time.

      Does the resistance change to above 55 Ohms?

      Yes 

      • Replace the module, that when disconnected, allows the CAN IHS Bus resistance to return to normal.
      • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .

      No 

      • Repair the short between the CAN IHS Bus (+) circuit and CAN IHS Bus (-) circuits.
      • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  10. CHECK THE CAN IHS BUS TERMINATION RESISTANCE AT THE BCM 
    1. Disconnect the related BCM.
    2. Using the appropriate back-probe pins, back-probe and measure the resistance of the CAN IHS Bus (+) circuit and CAN IHS Bus (-) circuit at the related BCM harness connector.

      Is the resistance approximately 120 Ohms?

      Yes 

      • Go To  12.

      No 

      • Go To Next Step.
  11. CHECK THE CAN IHS BUS TERMINATION RESISTANCE AT THE INSTRUMENT PANEL CLUSTER (IPC) 
    1. Reconnect the BCM.
    2. Disconnect the IPC.
    3. Using the appropriate back-probe pins, back-probe and measure the resistance between the CAN IHS Bus (+) circuit and CAN IHS Bus (-) circuit at the IPC.

      Is the resistance approximately 120 Ohms?

      Yes 

      No 

      • Go to Next Step.
  12. LOAD TEST THE POWER SUPPLY AND GROUND CIRCUIT TO THE BCM 

    Read the CIRCUIT LOAD TESTING PROCEDURE for information on building a simple load test tool, additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to CIRCUIT LOAD TESTING PROCEDURES .

    1. Disconnect the BCM harness connector.
    2. Connect one lead of the load test tool to the power supply circuit and the other lead of the load test tool to the ground circuit.
    3. Ensure that the power supply circuit is being powered on.
    4. If there is no resistance in either circuit the bulb on the load test tool should be illuminated and bright. Compare the brightness of the bulb in the load test tool to that of a direct connection to battery.
      NOTE:

      To verify with certainty that the circuit is good, perform a simple voltage drop test across the 3156 bulb of the load test tool. The voltage drop across the bulb should be equal to the voltage reading across the battery terminals if there is no resistance in either circuit. 

      NOTE:

      A 12-volt test light can be substituted for the load test tool, but only if the test light draws enough current to effectively load test the circuit. Many high impedance test lights draw very little amperage (less than 0.1 amps) and are not reliable to load test a circuit. To perform a proper load test of a circuit, the tool being used should draw more than approximately 0.75 amps. 

      Is the load test bulb illuminated and bright?

      Yes 

      • Go To Next Step

      No 

      • If the circuits fail the load test, remove the lead connected to the ground circuit and connect it to a good chassis ground. Check the bulb illumination and voltage drop across the 3156 bulb of the load test tool again. If the bulb is not bright or the voltage drop is still less than battery voltage, repair the battery supply circuit for an open or high resistance. If the bulb is bright or the voltage drop is now equal to battery voltage, repair the ground circuit for an open or high resistance.
      • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  13. CHECK THE BCM RELATED HARNESS CONNECTIONS 
    1. Disconnect all BCM 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 BCM 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 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 BCM DTCs.

      Did the DTC return?

      Yes 

      No 

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