Diagnostic Test

CHECK THE MODULE STATUS ON THE CAN C BUS
1. Turn the ignition on.
2. With the scan tool, read the CAN topology on the Vehicle View screen.
  Does the Vehicle View screen indicate that the Module is active on the bus?
  
  Yes
  - Perform the Intermittent conditions test. Refer to TESTING FOR AN INTERMITTENT CONDITION .
  No
  - Go To 2
CHECK THE FUSED B(+) CIRCUIT FOR AN OPEN OR SHORT TO GROUND
NOTE:
The CAN bus will remain active with the scan tool connected and the ignition off.

NOTE:
Leave the scan tool connected

and on the Vehicle View screen.
1. Turn the ignition off.
2. Disconnect the Drive Train Control Module (DTCM) harness connector.
3. With a 12-volt test light connected to ground, check the Fused B(+) circuit at the DTCM harness connector.
  NOTE:
  The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.
  
  Does the test light illuminate brightly?
  
  Yes
  - Go To 3
  No
  - Repair the Fused B(+) circuit for an open or short to ground.
  - Perform the DTCM VERIFICATION TEST. Refer to DTCM VERIFICATION TEST .
CHECK THE FUSED IGNITION CIRCUIT FOR AN OPEN OR SHORT TO GROUND
1. Turn the ignition on.
2. With a 12-volt test light connected to ground, check the Fused Ignition circuit at the DTCM harness connector.
  Does the test light illuminate brightly?
  
  Yes
  - Go To 4
  No
  - Repair the Fused Ignition circuit for an open or short to ground.
  - Perform the DTCM VERIFICATION TEST. Refer to DTCM VERIFICATION TEST .
CHECK THE GROUND CIRCUIT FOR AN OPEN OR HIGH RESISTANCE
1. With a 12-volt test light connected to 12 volts, check the Ground circuit at the DTCM harness connector.
  Does the test light illuminate brightly?
  
  Yes
  - Go To 5
  No
  - Repair the Ground circuit for an open or high resistance.
  - Perform the DTCM VERIFICATION TEST. Refer to DTCM VERIFICATION TEST .
CHECK THE CAN C1 BUS (+) CIRCUIT FOR AN OPEN OR HIGH RESISTANCE
1. Measure the voltage between ground and the CAN C1 Bus (+) circuit at the DTCM harness connector.
  Is the voltage below 2.5 volts?
  
  Yes
  - Repair the CAN C1 Bus (+) circuit for an open or high resistance.
  - Perform the DTCM VERIFICATION TEST. Refer to DTCM VERIFICATION TEST .
  No
  - Go To 6
CHECK THE CAN C1 BUS (-) CIRCUIT FOR AN OPEN OR HIGH RESISTANCE
1. Measure the voltage between ground and the CAN C1 Bus (-) circuit at the DTCM harness connector.
  Is the voltage below 1.3 volts?
  
  Yes
  - Repair the CAN C1 Bus (-) circuit for an open or high resistance.
  - Perform the DTCM VERIFICATION TEST. Refer to DTCM VERIFICATION TEST .
  No
  - Go To 7
CHECK RELATED HARNESS CONNECTIONS
1. Disconnect all DTCM Module 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 DTCM Module 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 DTCM Module DTCs.
  Did the DTC return?
  
  Yes
  - Replace the DTCM Module in accordance with the Service information. Refer to MODULE, DRIVETRAIN CONTROL (DTCM), REMOVAL AND INSTALLATION .
  - Perform the DTCM VERIFICATION TEST. Refer to DTCM VERIFICATION TEST .
  No
  - Repair the poor connections as necessary.
  - Perform the DTCM VERIFICATION TEST. Refer to DTCM VERIFICATION TEST .