Combination Meter

DTC U1101: PCM time-out (related to A/T) [A/T]

CAUTION:

- If DTC U1101 is set in the combination meter, always diagnose the CAN bus lines.
- Whenever the ECU is replaced, ensure that the communication circuit is normal.

DTC SET CONDITION

- The combination meter receives A/T control system-related signal from the PCM via CAN bus lines. If the display unit cannot receive the necessary signals, DTC U1101 will be set.

TECHNICAL DESCRIPTION (COMMENT)

CAUTION:
If the ignition switch is turned to the "ON" position without starting the engine, DTC (past trouble) U1101 may be set on the combination meter (incorporating meter-ECU) after three minutes.

Current trouble

- Connector(s) or wiring harness in the CAN bus lines between the PCM and the combination meter, the power supply system to the PCM, the PCM itself, or the combination meter may be defective.
Past trouble

- Carry out diagnosis with particular emphasis on connector(s) or wiring harness in the CAN bus lines between the PCM and the combination meter, and the power supply system to the PCM. For diagnosis procedures, refer to "How to cope with past trouble" How to Treat Past Trouble ).
NOTE:
For a past trouble, you may not find it 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 Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunction How to Cope With Intermittent Malfunctions .) 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 CAN Bus Line Diagnostics Flow ).

TROUBLESHOOTING HINTS

- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector.
- Malfunction of the PCM.
- Malfunction of the 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 A/T system diagnostic trouble code.

Check if an A/T system diagnostic trouble code is set.

(1)Turn the ignition switch "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 A/T system by referring to A/T Diagnosis - Diagnostic Trouble Code Chart Automatic Transmission.

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.

ABS-ECU
- DTC U1101: PCM time-out (related to A/T)
ETACS-ECU
- DTC U1101: PCM time-out (related to A/T)
(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 PCM 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 An intermittent malfunction is suspected. How to Cope With Intermittent Malfunctions.

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.