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Home >> Jeep >> 2021 >> Compass Trailhawk >> Repair and Diagnosis (Single Page) >> General Information >> OEM General Information >> (Global Telematics Box Module - Electrical Diagnostics) >> DTC Troubleshooting >> B1555-15-Emergency Call Button Backlight Led Control-Circuit Short To Battery Or Open >> Diagnostic Test

Diagnostic Test

  1. CHECK FOR AN ACTIVE DTC 
    1. With the scan tool, read DTCs in all Electronic Control Units (ECUs) 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 TBM2 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 TBM2 DTCs.

      Did the DTC return?

      Yes 

      • Go To  2

      No 

  2. CHECK THE INSIDE REARVIEW MIRROR 
    1. Turn the ignition off.
    2. Disconnect the Inside Rearview Mirror harness connector.
    3. Turn the ignition on.
    4. Wait 10 seconds.
    5. With the scan tool, read DTCs.

      Is the DTC active?

      Yes 

      • Go To  3

      No 

  3. CHECK THE (X804) EMERGENCY BACKLIGHT CONTROL CIRCUIT FOR A SHORT TO VOLTAGE 
    1. Turn the ignition off.
    2. Disconnect the harness connector at the component of the circuit being tested. Note:  Use the appropriate SYSTEM WIRING DIAGRAM as a guide to follow the path of the circuit.
    3. Turn the ignition on.
    4. Using a DVOM, measure the voltage of the circuit being tested at the component harness connector.

    Is there any voltage present?

    Yes 

    • Go To  4

    No 

    • Go To  5
  4. ISOLATE AND CHECK THE (X804) EMERGENCY BACKLIGHT CONTROL CIRCUIT FOR A SHORT TO ANOTHER CIRCUIT AT THE TBM2 HARNESS CONNECTOR 
    1. The ignition must be off when performing a resistance check to find a short between circuits.
    2. Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and every component harness connector containing the circuit being tested. At this time leave all in-line connectors connected. Note:  Use the appropriate SYSTEM WIRING DIAGRAM as a guide to follow the path of the circuit.
    3. Connect one lead of the DVOM to the circuit being tested at the ECU harness connector.
    4. With the other lead of the DVOM probe all other circuits at the ECU harness connector.
    NOTE:

    When probing a circuit at an Electronic Control Unit (ECU) harness connector, always use an appropriate back probing tool to prevent any possible damage to the ECU terminals.

    NOTE:

    With the circuit isolated there should be no continuity between the circuit being tested and any other circuit.

    Is there continuity between the circuit being tested and any other circuit?

    Yes 

    • Repair the short between the circuits that have continuity. Use the appropriate SYSTEM WIRING DIAGRAM as a guide to trace the circuits and look for any in-line connectors to help isolate the location of the short.
    • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .

    No 

    • Go To  5
  5. ISOLATE AND CHECK THE (X804) EMERGENCY BACKLIGHT CONTROL CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. The ignition must be off when checking the continuity of a circuit.
    2. Isolate the circuit by disconnecting the Electronic Control Unit (ECU) and the component harness connector containing the circuit being tested. Note:  Use the appropriate SYSTEM 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 an Electronic Control Unit (ECU) harness connector, always use an appropriate back probing tool to prevent any possible damage to the ECU terminals.

    Is the resistance below 3.0 Ohms?

    Yes 

    • Go To  6

    No 

    • Repair the circuit for an open or high resistance.
    • Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  6. CHECK RELATED HARNESS CONNECTIONS 
    1. Disconnect all TBM2 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 TBM2 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 TBM2 DTCs.

      Did the DTC return?

      Yes 

      No