Code No.U1120 Failures Information on Engine-ECU <M/T> or Engine-A/T-ECU <A/T> (Related to Engine)


caution If diagnosis code U1120 is set in the centre display or multi display station, always diagnose the CAN bus lines.

TROUBLE JUDGMENT


The centre display unit or multi display station receives the vehicle speed signal for the centre display unit or multi display station from the combination meter via CAN bus lines. If failure information is sent to the vehicle speed signal for the centre display unit or multi display station, diagnosis code U1120 will be set.

PROBABLE CAUSES



DIAGNOSSIS PROCEDURE


STEP 1. M.U.T.-III CAN bus diagnostics


Use the M.U.T.-III to diagnose the CAN bus lines.

Q. Is the check result satisfactory?

Go to Step 2.

Repair the CAN bus lines (Refer to GROUP 54D - Troubleshooting ). Repair the CAN bus line and go to Step 6.

STEP 2. M.U.T.-III other system diagnosis code


Check whether the combination meter-related diagnosis code is set.

Q. Is the diagnosis code set?

Diagnose the combination meter (Refer to GROUP 54A - Troubleshooting ).

Go to Step 3.

STEP 3. M.U.T.-III other system diagnosis code


Check if a diagnosis code, which relates to CAN communication-linked systems below, is set.

Q. Is the diagnosis code set?

Go to Step 4.

Go to Step 5.

STEP 4. Check whether the diagnosis code is reset.


Replace the centre display unit or multi display station temporarily, and then check that the diagnosis code is not reset.
(1)Replace the centre display unit or multi display station temporarily.
(2)Erase the diagnosis code.
(3)Turn the ignition switch to "ON" position.
(4)Check if the diagnosis code is set.

Q. Is the check result satisfactory?

Replace centre display unit or multi display station and then go to step 6.

Go to Step 5.

STEP 5. Check whether the diagnosis code is reset.


Replace the combination meter temporarily, and then check that the diagnosis code is not reset.
(1)Replace the combination meter temporarily.
(2)Erase the diagnosis code.
(3)Turn the ignition switch to "ON" position.
(4)Check if the diagnosis code is set.

Q. Is the check result satisfactory?

Replace combination meter and then go to step 6.

A poor connection, open circuit or other intermittent malfunction is present in the lines between the centre display unit or multi display station and the combination meter (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).

STEP 6. Check whether the diagnosis code is reset.


Recheck if the diagnosis code is set.
(1)Erase the diagnosis code.
(2)Turn the ignition switch to "ON" position.
(3)Check if the diagnosis code is set.

Q. Is the check result satisfactory?

The procedure is complete.

Go to Step 1.