Combination Meter

DTC U1120: Failure information on ECM [M/T] or PCM [A/T] (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.

DTC SET CONDITION

The combination meter communicates with the ECM [M/T] or PCM [A/T] via CAN bus line. If failure information is sent to the ECM [M/T] or PCM [A/T], DTC U1120 will be set.

TECHNICAL DESCRIPTION (COMMENT)

Current trouble

- The ECM [M/T] or PCM [A/T] or the combination meter may be defective.
Past trouble

- Carry out diagnosis with particular emphasis on connector(s) or wiring harness between the ECM [M/T] or PCM [A/T] and the combination meter. For diagnosis procedures, refer to "How to cope with past trouble" How to Cope With Intermittent Malfunctions ).

TROUBLESHOOTING HINTS

- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
- Malfunction of ECM [M/T] or PCM [A/T]
- Malfunction of combination meter

DIAGNOSIS

Required Special Tools:

- 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.

Use scan tool MB991958 to diagnose the CAN bus lines.

(1)
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).

Connect scan tool MB991958 to the data link connector.
(2)Turn the ignition switch to "ON" position.
(3)Diagnose the CAN bus line.
(4)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the check result satisfactory?

YES Go to Step 2.

NO Repair the CAN bus lines CAN Bus Diagnostics Chart).

STEP 2. Using scan tool MB991958, read the MFI system diagnostic trouble code.

Check if an MFI system diagnostic trouble code is set.

(1)Turn the ignition switch to "ON" position.
(2)Read the diagnostic trouble code.
(3)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the DTC set?

YES Diagnose the MFI system by referring to MFI Diagnosis - Diagnostic Trouble Code Chart Multiport Fuel Injection (MFI) MFI Diagnosis - Diagnostic Trouble Code Chart Multiport Fuel Injection (MFI).

NO Go to Step 3.

STEP 3. Using scan tool MB991958, read the for any diagnostic trouble code.

(1)Turn the ignition switch to the "ON" position.
(2)Check if a diagnostic trouble code, which relates to CAN communication-linked systems below, is set.

- ETACS-ECU
- A/C-ECU
(3)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the DTC set?

YES Go to Step 4.

NO Go to Step 5.

STEP 4. Recheck for diagnostic trouble code.

When the ECM [M/T] or PCM [A/T] is replaced, register the encrypted code. Immobilizer System, and then check that the diagnostic trouble code is not reset.

(1)Turn the ignition switch to "ON" position.
(2)Erase the diagnostic trouble code.
(3)Turn the ignition switch to the "LOCK" (OFF) position.
(4)Turn the ignition switch to "ON" position.
(5)Check if the diagnostic trouble code is set.
(6)Turn the ignition switch to the "LOCK" (OFF) position.

Q. Is the check result normally?

YES The procedure is complete.

NO Replace the combination meter.

STEP 5. Recheck for diagnostic trouble code.

Replace the combination meter, and then check that the diagnostic trouble code is not reset.