Diagnostic Test

TEST FOR INTERMITTENT CONDITION
1. Turn the ignition on.
2. With the scan tool, record and erase FCM DTCS
3. Cycle the ignition from on to off 3 times.
4. Turn the ignition on.
5. With the scan tool, read active FCM DTC's.
Q: Does the scan tool display this DTC as active?

Yes :
- Go To 2
No :
- The conditions that caused this code to set are not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors.
ATTEMPT TO ISOLATE THE OPEN CONDITION

Fig 1: Identifying Front Control Modules Connector Terminal
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
1. Connect the scan tool.
2. Turn the ignition on.
3. Select System select.
4. Look through the list of ECUs for any that are grayed out.
  NOTE: If an ECU is grayed out, it is not communicating, indicating that the module is not active on the Bus network.
  
  NOTE: If any module is not communicating, perform the appropriate No Response test procedure before proceeding.
5. Turn the ignition off.
6. Gain access to the Front Control Module C1 harness connector, but do not disconnect.
7. Using a fused jumper wire, connect one end to ground and with the other end backprobe the CAN B Bus (-) circuit at the FCM C1 harness connector.
8. Turn the ignition on.
9. With the scan tool, select System select.
10. Look for a grayed out ECU (s).
Q: Are there any grayed out ECUs?

Yes :
- Go To 3
No :
- Check backprobe connection to ground, make sure it is proper. The CAN B Bus open DTC may no longer be active, it may be stored. Check all module connections
- Perform BODY VERIFICATION TEST - VER 1 . (Refer to ELECTRONIC CONTROL MODULES/MODULE - FRONT CONTROL/DIAGNOSIS AND TESTING).
ATTEMPT TO ISOLATE THE OPEN CONDITION - MULTIPLE GRAYED OUT ECUs
1. With the scan tool continue monitoring the network status screen.
Q: Are there multiple grayed out ECUs?

Yes :
- The most likely cause of this condition is an open CAN B Bus (+) circuit between a common CAN B Bus splice and the modules that are grayed out. Use the wiring diagrams will help you determine where open condition exists.
- Perform BODY VERIFICATION TEST - VER 1 . (Refer to ELECTRONIC CONTROL MODULES/MODULE - FRONT CONTROL/DIAGNOSIS AND TESTING).
No :
- Go To 4
(D55) CAN B BUS (+) CIRCUIT OPEN - SINGLE GRAYED OUT ECU
1. Turn the ignition off.
2. Disconnect the module that is grayed out.
3. Turn the ignition on.
4. Measure the voltage between the (D55) CAN B Bus (+) circuit and ground.
Q: Is there any voltage present?

Yes :
- Inspect the connector and terminal for damage, inspect for spread terminals, or push out terminals. If OK, replace the module that displayed the red X next to it in accordance with the service information.
- Perform BODY VERIFICATION TEST - VER 1 . (Refer to ELECTRONIC CONTROL MODULES/MODULE - FRONT CONTROL/DIAGNOSIS AND TESTING).
No :
- Repair the (D55) CAN B Bus (+) circuit for an open between the next common splice and the module that has the red X displayed next to it. Use the wiring diagrams will help you determine where open condition exists.
- Perform BODY VERIFICATION TEST - VER 1 . (Refer to ELECTRONIC CONTROL MODULES/MODULE - FRONT CONTROL/DIAGNOSIS AND TESTING).