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Diagnostic Test

  1. READ AND RECORD DTCS AND ENVIRONMENTAL DATA - ERASE DTCS AND CHECK FOR THE DTC TO RETURN 
    NOTE:

    Diagnose and repair any other LIN Bus related DTCs before proceeding with this diagnostic procedure.

    1. With the scan tool, read DTCs in all Electronic Control Units (ECU's) and record on the repair order.
    2. With the scan tool, run a vehicle Scan Report, or record the Environmental Data related to the DTCs.
    3. With the scan tool, erase all DTCs.
    4. Turn the ignition off for a minimum of 10.0 seconds.
    5. Turn the ignition on.
    6. Using the recorded Environmental Data and the When Monitored Conditions above, operate the vehicle in the conditions that set the DTC.
    7. With the scan tool, read Body Control Module (BCM) DTCs.

      Did the DTC return?

      Yes 

      • Go To  2

      No 

  2. DISCONNECT THE UPPER SWITCH BANK MODULE HARNESS CONNECTOR AND CHECK THE (A232) FUSED B(+) CIRCUIT BY LOAD TESTING THE CIRCUIT 
    1. Disconnect the component harness connector to isolate the Fused B(+) circuit.
    2. Connect the positive lead of the load test tool to the Fused B(+) circuit at the component harness connector (A). Note:  refer to the diagram below.
    3. Connect the negative lead of the load test tool to the ground circuit of the Battery or a good chassis ground.
    4. Make sure the circuit being tested is being powered on. If the circuit being tested is an ignition feed for example, the ignition must be on. If testing an output from a relay, verify that the relay is energized and on.
    5. The bulb on the load test tool should be illuminated and bright if there is no resistance in the circuitry.
      NOTE:

      Note: Why load test a circuit?  A load test is used to determine if a circuit is capable of carrying the amperage needed to perform properly. The 3156 Bulb in the load tool illustrated, is a simple but effective method of testing circuit functionality. A 3156 Bulb has approximately 6.0 Ohms of resistance when the bulb is powered  and draws approximately 2.0 amps of current. Read the CIRCUIT VOLTAGE DROP AND LOAD TESTING PROCEDURES for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to: VOLTAGE DROP TEST PROCEDURE and CIRCUIT LOAD TESTING PROCEDURES .

      NOTE:

      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.

      NOTE:

      Note: Why perform a Voltage Drop Test:  To verify with certainty there is not any resistance in the circuit being tested, perform a simple voltage drop test across the 3156 Bulb of the load test tool. To do so perform the following:

      • 1. Connect the leads of a DVOM to the alligator clips on the load test tool while the load test tool is connected in series with the circuit.
      • 2. Compare the voltage drop across the bulb to the voltage reading across the Battery terminals.
      • 3. The voltage dropped across the bulb should be equal to the voltage reading across the Battery terminals if there is no resistance in the circuit being tested.

      Example:  2.0 Ohms of resistance in the circuit being tested will cause the voltage measurement across the bulb to be 25% less than when compared to Battery voltage. The reason for this is that the 2.0 Ohms in the circuit makes up 25% of the total circuit resistance of 8.0 Ohms. Read the CIRCUIT VOLTAGE DROP AND LOAD TESTING PROCEDURES for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to: VOLTAGE DROP TEST PROCEDURE and CIRCUIT LOAD TESTING PROCEDURES .

      NOTE:

      When probing a circuit at any harness connector, always use an appropriate probing tool to prevent any possible damage to the harness connector terminals.

      NOTE:

      Compare the brightness of the bulb in the load test tool to that of a direct connection to Battery.

      GC0174938Courtesy of CHRYSLER GROUP, LLC

      Is the load test bulb illuminated and bright?

      Yes 

      • Go To  3

      No 

      • Remove the Fuse for the Upper Switch Bank Module and inspect it for an open.
      • If Fuse Is Good:  Install the Fuse that was removed and repair the open or high resistance in the Fused Ignition circuit. Using the wiring diagrams as a guide inspect the circuit, related in-line connectors and splice connections for an open or high resistance.
      • If Fuse Is Open:  Repair the short to ground in the Fused Ignition circuit. Using the wiring diagrams as a guide inspect the circuit, related in-line connectors and splice connections for a short. Replace the Fuse that was removed.
      • Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .
  3. CHECK THE (Z910) GROUND CIRCUIT FOR AN OPEN OR HIGH RESISTANCE BY LOAD TESTING THE CIRCUIT 
    1. Connect the positive lead of the load test tool to a 12 volt circuit at the component harness connector.
    2. Connect the negative lead of the load test tool to the ground circuit at the component harness connector (A). Note:  refer to the diagram below.
    3. The bulb on the load test tool should be illuminated and bright if there is no resistance in the circuitry.
      NOTE:

      Note: Why load test a circuit?  A load test is used to determine if a circuit is capable of carrying the amperage needed to perform properly. The 3156 Bulb in the load tool illustrated, is a simple but effective method of testing circuit functionality. A 3156 Bulb has approximately 6.0 Ohms of resistance when the bulb is powered  and draws approximately 2.0 amps of current. Read the CIRCUIT VOLTAGE DROP AND LOAD TESTING PROCEDURES for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to: VOLTAGE DROP TEST PROCEDURE and CIRCUIT LOAD TESTING PROCEDURES .

      NOTE:

      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.

      NOTE:

      Note: Why perform a Voltage Drop Test:  To verify with certainty there is not any resistance in the circuit being tested, perform a simple voltage drop test across the 3156 Bulb of the load test tool. To do so perform the following:

      • 1. Connect the leads of a DVOM to the alligator clips on the load test tool while the load test tool is connected in series with the circuit.
      • 2. Compare the voltage drop across the bulb to the voltage reading across the Battery terminals.
      • 3. The voltage dropped across the bulb should be equal to the voltage reading across the Battery terminals if there is no resistance in the circuit being tested.

      Example:  2.0 Ohms of resistance in the circuit being tested will cause the voltage measurement across the bulb to be 25% less than when compared to Battery voltage. The reason for this is that the 2.0 Ohms in the circuit makes up 25% of the total circuit resistance of 8.0 Ohms. Read the CIRCUIT VOLTAGE DROP AND LOAD TESTING PROCEDURES for information on building a simple load test tool and for additional load testing information and alternative methods of load testing or voltage drop testing a circuit. Refer to: VOLTAGE DROP TEST PROCEDURE and CIRCUIT LOAD TESTING PROCEDURES .

      NOTE:

      When probing a circuit at any harness connector, always use an appropriate probing tool to prevent any possible damage to the harness connector terminals.

      NOTE:

      Compare the brightness of the bulb in the load test tool to that of a direct connection to Battery.

      GC0174957Courtesy of CHRYSLER GROUP, LLC

      Is the load test bulb illuminated and bright?

      Yes 

      • Go To  4

      No 

      • Repair the ground circuit for an open or high resistance. Using the wiring diagrams as a guide, make sure to also inspect any related in-line connectors or splice connections.
      • Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .
  4. DISCONNECT THE BCM HARNESS CONNECTOR(S) AND CHECK THE (D401) LIN BUS 1 CIRCUIT FOR AN OPEN OR HIGH RESISTANCE 
    1. The ignition must be off when checking the resistance of a circuit.
    2. Disconnect all Electronic Control Unit (ECU) harness connectors containing the circuit being tested. Note:  Use the wiring diagram as a guide to follow the path of the circuit.
    3. Before measuring the resistance of any circuit, first measure the resistance between the two leads of the DVOM. Note:  The meter leads can add resistance to the measurement value.
    4. Connect one lead of the DVOM to the circuit being tested at the component harness connector.
    5. Connect the other lead to the circuit being tested at the ECU harness connector and measure the resistance of the circuit.
      NOTE:

      When probing a circuit at any harness connector, always use an appropriate probing tool to prevent any possible damage to the harness connector terminals.

      Is the resistance above 3.0 Ohms?

      Yes 

      • Repair the circuit for an open or high resistance.
      • Perform the BODY VERIFICATION TEST. Refer to: BODY VERIFICATION TEST .

      No 

      • Go To  5
  5. RECONNECT THE BCM HARNESS CONNECTOR(S) AND CHECK THE VOLTAGE ON THE (D401) LIN BUS 1 CIRCUIT AT THE UPPER SWITCH BANK MODULE 
    1. Connect all Electronic Control Unit (ECU) harness connectors containing the circuit being tested.
    2. Turn the ignition on.
    3. Using a DVOM, measure the voltage on the circuit being tested at the component harness connector.
      NOTE:

      When probing a circuit at any harness connector, always use an appropriate probing tool to prevent any possible damage to the harness connector terminals.

      Is there any voltage present?

      Yes 

      No 

      • Go To  6
  6. DISCONNECT RELATED MODULE HARNESS CONNECTIONS AND INSPECT FOR PROBLEMS 
    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. Connect all BCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
    6. Connect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
    7. Connect 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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