Diagnostic Test

CHECK FOR AN ACTIVE DTC
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 2.
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 2
  No
  - Perform the appropriate INTERMITTENT CONDITION diagnostic procedure. Refer to TESTING FOR AN INTERMITTENT CONDITION .
CHECK THE CAN C1 BUS (+) AND (-) CIRCUITS FOR A SHORT TO VOLTAGE
NOTE:
Disconnecting the Radio Frequency (RF) Hub Module or 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 C1 Bus (+) circuit at Security Gateway (SGW) Module C1 harness connector - terminal 5.
3. Using the appropriate back-probe pins, back-probe and measure the voltage on the CAN C1 Bus (-) circuit at SGW Module C1 harness connector - terminal 12.
  Is the voltage above 10.0 volts on the CAN C1 Bus (+) or CAN C1 Bus (-) circuit?
  
  Yes
  - Diagnose the short to voltage on the CAN C1 Bus (+) or CAN C1 Bus (-) circuit. Disconnecting each module on the CAN C1 Bus, one at a time, can isolate portions of the CAN Bus to assist in determining the location of the concern. Repair the shorted circuit or replace the module, that when disconnected, allows the CAN Bus voltage to return to normal.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 3
CHECK THE CAN C1 BUS (+) AND (-) 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 C1 Bus (+) circuit at SGW Module C1 harness connector - terminal 5.
5. Using the appropriate back-probe pins, back-probe and check for continuity between ground and the CAN C1 Bus (-) circuit at SGW Module C1 harness connector - terminal 12.
  Is there continuity between ground and the CAN C1 Bus (+) or CAN C1 Bus (-) circuit?
  
  Yes
  - Diagnose the short to ground on the CAN C1 Bus (+) or CAN C1 Bus (-) circuit. Disconnecting each module on the CAN C1 Bus, one at a time, can isolate portions of the CAN Bus to assist in determining the location of the concern. Repair the shorted circuit or replace the module, that when disconnected, allows the CAN Bus voltage to return to normal.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 4
CHECK FOR CORRECT CAN C1 BUS TERMINATION RESISTANCE
1. Using the appropriate back-probe pins, back-probe and measure the resistance of the CAN C1 Bus (+) circuit and CAN C1 Bus (-) circuit between SGW Module C1 harness connector - terminal 5 and terminal 12.
  Is the resistance below 53.5 Ohms?
  
  Yes
  - Diagnose the short between the CAN C1 Bus (+) circuit and the CAN C1 Bus (-) circuit. Disconnecting each module on the CAN C1 Bus, one at a time, can isolate portions of the CAN Bus to assist in determining the location of the concern. Repair the shorted circuit or replace the module, that when disconnected, allows the CAN Bus resistance to return to normal.
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Go To 5
CHECK 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
  - Replace the Body Control Module (BCM) in accordance with the Service Information. Refer to MODULE, BODY CONTROL (BCM), REMOVAL .
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  No
  - Perform the BODY VERIFICATION TEST. Refer to BODY VERIFICATION TEST .
  - Test complete.