U1128
DTC U1128: Failure information on combination meter.CAUTION:
- If DTC U1128 is set in the ETACS-ECU, always diagnose the CAN main bus line.
- Whenever the ECU is replaced, ensure that the communication circuit is normal.
- The combination meter-related DTC may be set when DTC U1128 is set. (For details refer to Intersystem Affiliated DTC - Reference Table.) Diagnose the combination meter first when the combination meter related DTC is set.
TROUBLE JUDGMENT
The ETACS-ECU receives combination meter-related signal from the combination meter via the CAN bus lines. If a fail-safe related data is contained in the signal from the combination meter, DTC U1128 will be stored.
TECHNICAL DESCRIPTION (COMMENT)
Current trouble
- The wiring harness wire or connectors may have loose, corroded, or damage terminals, or terminals pushed back in the connector, the ECM
Past trouble
- If DTC U1128 is stored as a past trouble, carry out diagnosis with particular emphasis on wiring and connector(s) in the CAN bus line between the combination meter and the ETACS-ECU, and the power supply system to the combination meter. For diagnosis procedures, refer to "How to cope with past trouble" (Refer to How to treat past trouble).
NOTE: You cannot find a past trouble, by the M.U.T.-III CAN bus diagnostics even if there is a failure in CAN bus lines. In this case, Refer to How to Cope with Intermittent Malfunction and check the CAN bus lines. You can narrow down the possible cause of the trouble by referring to the DTC, which is set regarding the CAN communication-linked ECUs (Refer to Information Bus, CAN Bus Line Diagnostic Flow).
TROUBLESHOOTING HINTS
The ETACS-ECU may be defective
DIAGNOSIS
Required Special Tools:
- MB991223: Harness Set
- MB992006: Extra Fine Probe
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: M.U.T.-III USB Cable
- MB991910: M.U.T.-III Main Harness A
STEP 1. Using scan tool MB991958, diagnose the CAN bus line.
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958. Refer to "How to connect SWS monitor."
2. Turn the ignition switch to the "ON" position.
3. Diagnose the CAN bus line.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the CAN bus line found to be normal?
YES: Go to Step 2.
NO: Repair the CAN bus line (Refer to Information Bus, Diagnosis).
STEP 2. Using scan tool MB991958, read the ECM
Check whether engine and transaxle DTCs are set or not.
1. Turn the ignition switch to the "ON" position.
2. Check for engine and transaxle DTCs.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?
YES: Diagnose the ECM
NO: Go to Step 3.
STEP 3. Using scan tool MB991958, read the combination meter diagnostic trouble code.
Check whether the combination meter-related DTC is set.
1. Turn the ignition switch to the "ON" position.
2. Check whether the combination meter-related DTC is set.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?
YES: Diagnose the combination meter (Refer to Diagnosis in Instrument Cluster/Carrier).
NO: Go to Step 4.
STEP 4. Recheck for diagnostic trouble code.
Check again if the DTC is set.
1. Turn the ignition switch to the "ON" position.
2. Check if the DTC is set.
3. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?
YES: Replace the ETACS-ECU. When the ETACS-ECU is replaced, register the encrypted code. Refer to Encrypted Code Registration Criteria Table in Antitheft and Alarm Systems. On completion, verify that the DTC is not reset.
NO: There is an intermittent malfunction such as poor engaged connector(s) or open circuit (Refer to How to Cope with Intermittent Malfunction).