Combination Assembly
DTC U1120: Failure Information on Powertrain Control Module (Related to Engine)CAUTION:
- If DTC U1120 is set in the combination meter, diagnose the CAN main bus line.
- If DTC U1120 has been set, SWS related DTC 021 is also set. After SWS has been diagnosed, don't forget to erase DTC 021.
- The engine control system- related DTC may be set when DTC U1120 is set. (For details refer to Intersystem Affiliated DTC Reference Table) Diagnose the engine control system first when the engine control system- related DTC is set.
DTC SET CONDITION
The combination meter communicates with the powertrain control module via CAN bus line. If failure information is sent to the powertrain control module, DTC U1120 will be set.
TECHNICAL DESCRIPTION (COMMENT)
Current trouble
- The powertrain control module or the combination meter may be defective.
Past trouble
- Carry out diagnosis with particular emphasis on connector(s) or wiring harness between the powertrain control module and the combination meter. For diagnosis procedures, refer to "How to cope with past trouble" (Refer to How to Use Troubleshooting/Inspection Service Points).
TROUBLESHOOTING HINTS
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector.
- Malfunction of powertrain control module.
- Malfunction of combination meter.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: Vehicle Communication Interface (V.C.I.)
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A (Vehicles with CAN communication system)
STEP 1. Using scan tool MB991958, diagnose the CAN bus line.
Use scan tool MB991958 to diagnose the CAN bus lines.
1. Connect scan tool MB991958 to the data link connector.
2. Turn the ignition switch to "ON" position.
3. Diagnose the CAN bus line.
Q: Is the check result satisfactory?
YES: Go to Step 2.
NO: Repair the CAN bus lines (Refer to Information Bus, Diagnosis - Can Bus Diagnostic Chart ). On completion, go to Step 6.
STEP 2. Using scan tool MB991958, read the MFI system diagnostic trouble code.
Check if an MFI system DTC is set.
Q: Is the DTC set?
YES: Diagnose the MFI system by referring to MFI Diagnosis - Diagnostic Trouble Code Chart.
NO: Go to Step 3.
STEP 3. Using scan tool MB991958, read the diagnostic trouble code related to the other system.
Check if a DTC, which relates to CAN communication-linked systems below, is set.
- ABS-ECU
DTC U1120: Failure information on powertrain control module (related to engine)
- Multi-center display
DTC 020: Failure information on powertrain control module (related to engine)
- A/C-ECU
DTC U1120: Failure information on powertrain control module (related to engine)
Q: Is the DTC set?
YES: Go to Step 4.
NO: Go to Step 5.
STEP 4. Recheck for diagnostic trouble code.
Recheck if the DTC is set.
1. Erase the DTC.
2. Turn the ignition switch to "ON" position.
3. Check if the DTC is set.
Q: Is the check result satisfactory?
YES: A poor connection, open circuit or other intermittent malfunction is present in the lines between the powertrain control module and the combination meter (Refer to How to Use Troubleshooting/ Inspection Service Points - How to Cope with Intermittent Malfunction).
NO: Replace powertrain control module and then go to step 6.
STEP 5. Recheck for diagnostic trouble code.
Recheck if the DTC is set.
1. Erase the DTC.
2. Turn the ignition switch to "ON" position.
3. Check if the DTC is set.
Q: Is the check result satisfactory?
YES: A poor connection, open circuit or other intermittent malfunction is present in the lines between the powertrain control module and the combination meter (Refer to How to Use Troubleshooting/ Inspection Service Points - How to Cope with Intermittent Malfunction).
NO: Replace combination meter and then go to step 6.
STEP 6. Recheck for diagnostic trouble code.
Recheck if the DTC is set.
1. Erase the DTC.
2. Turn the ignition switch to "ON" position.
3. Check if the DTC is set.
Q: Is the check result satisfactory?
YES: The procedure is complete.
NO: Go to Step 1.