Diagnostic Test

If possible, pay particular attention to the ambient air temperature when the DTC set. Electrical connections, such as wire terminal connections, solder joints, and printed circuit board traces will expand and contract due to temperature changes. If the DTC was set in extreme cold conditions, the vehicle may need to be tested in extreme cold conditions.

IMPORTANT:  Poor wire harness terminal connections are a big contributor to intermittent electrical connections. Follow the directions below to help identify the source of the intermittent electrical condition:

• Record all DTCs on the repair order.
• Run a Vehicle Scan Report.
• With a scan tool, check all electronic control modules for software updates that are related to the customer complaint.
  • Update the electronic control module(s) as needed.
• Use the Search function in TechCONNECT to search for any related information under SERVICE ACTIONS/TIPS.
  • Perform any Service Bulletins or other procedures that may apply.
• With the scan tool, perform any applicable System Tests or Actuations to the component(s) that may cause the DTC to set.
• For Communication DTCs, perform the scan tool LOSS OF COMM TEST. This will force the modules on the CAN C bus to continuously ping each other every one second. Wiggle the applicable wires while reading the NUMBER OF NO RESPONSES. A value above 0 indicates the location of a circuit fault.
• For Relay related DTCs, with the scan tool, actuate the Relay and wiggle the related wiring harness and connectors to attempt to interrupt the actuation.
• Review any applicable scan tool Freeze Frame, Event and Environmental Data information and attempt to duplicate the conditions under which the DTC set. If needed, operate the vehicle.
• Monitor the scan tool parameters related to the DTC while wiggling the related wiring harness and connectors. Look for the DTC status or parameter values to change.
  • Using a data recorder and/or a lab scope may help diagnose intermittent conditions.
• Using the appropriate SYSTEM WIRING DIAGRAMS as a guide, visually inspect the related wiring harness and check for the following:
  • Proper wiring harness routing.
  • Chafed, pierced, pinched or open wiring harness insulation.
  • Partially broken wires.
  • Wiring or wiring strands broken inside of the insulation.
• If multiple DTCs are set, use the appropriate SYSTEM WIRING DIAGRAMS and inspect the following for poor connections or corrosion:
  • Module power and ground circuits.
  • Sensor reference and return circuits.
  • Chassis grounds.
  • Any common circuits.
• Disconnect all the related module, component and in-line wiring harness connectors and perform the following steps:
  1. Visually inspect the connector casings, locks, and weather-proof seals for any damage or water intrusion.
  2. Visually inspect for broken, bent, pushed out, or corroded terminals.
  3. Visually inspect the connectors and terminals for overheating due to a poor connection (terminals may be discolored due to excessive current draw).
  4. Verify the terminals in the connectors are fully seated into the connector/component and properly locked into position.
  5. Inspect the male and female connector terminals for proper terminal tension (drag test).
  6. Connect all the related module, component and in-line wiring harness connectors and verify they are fully seated.
• Check for any aftermarket accessories and verify they are installed and operate correctly. If needed, disconnect them to verify they are not the cause of the problem.
• For additional information on performing circuit tests .
• Before releasing the vehicle, perform the following steps:
  1. Verify all connectors are fully seated, connected and properly locked.
  2. With the scan tool, erase DTCs.
  3. Using the recorded Freeze Frame Data (if available), Event Data (if available), Environmental Data, and the When Monitored information for the DTC being diagnosed, operate the vehicle in the conditions that set the DTC.
  4. With the scan tool, read DTCs.
     • If the DTC sets, refer to the appropriate DTC procedure.

• Review the code monitored and set conditions for any DTCs that are stored and attempt to reproduce the conditions listed.
  WARNING:

  Maintain a safe distance from all airbags while performing the following steps. Failure to follow these instructions may result in possible serious or fatal injury.

  WARNING:

  On vehicles equipped with the high voltage system, disconnecting the 12-volt battery negative cable alone will not power down the 12-volt system. You must perform the 12-volt Power Down procedure before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.

• Wiggle the wiring harness and connectors of the related airbag circuit, sensor, or component.
• Disconnect components and inspect the harness and connectors for damage.
• Reconnect components and ensure they are properly seated.
  WARNING:

  Turn the ignition on, then reconnect the 12-volt battery and wait two minutes before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.

• If codes are related to the Driver Airbag circuits, rotate the steering wheel from stop to stop.
• Turn the ignition off.

Was the source of the customer complaint found or did any DTCs appear and stay active?

Yes 

• Make the appropriate repairs and either perform the RESTRAINTS SYSTEM VERIFICATION TEST. Refer to RESTRAINTS SYSTEM VERIFICATION TEST  . for the appropriate diagnostic procedure. Refer to DTC TROUBLESHOOTING .

No 

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• Using the appropriate SYSTEM WIRING DIAGRAM/schematic as a guide, inspect the wiring and connectors related to the stored code or component in question.
• Look for chafed, pierced, pinched, or partially broken wires and broken, bent, pushed out, spread, corroded, or contaminated terminals.
• Reconnect any disconnected components and harness connectors and ensure they are properly seated.
  WARNING:

  Turn the ignition on, then reconnect the battery and wait two minutes before proceeding. Failure to follow these instructions may result in possible serious or fatal injury.

• If numerous trouble codes were set, use a schematic and inspect any common ground or supply circuits.

Was the source of the intermittent condition located?

Yes 

• Make the appropriate repairs and perform the RESTRAINTS SYSTEM VERIFICATION PROCEDURE. Refer to RESTRAINTS SYSTEM VERIFICATION TEST  .

No 

• The problem cannot be found at this time.