If the diagnosis
code No. U1000 is set, be sure to diagnose the CAN bus line.
Before replacing the ECU or combination meter, ensure that the power supply circuit, the
earth circuit and the communication circuit are normal.
DIAGNOSTIC FUNCTION
If the signal from OSS-ECU cannot be received, the combination meter sets the diagnosis
code No. U1000.
JUDGEMENT CRITERIA
With the ignition switch is at ON position, the diagnosis code No. U1190 is not stored
and the diagnosis code No. U1195 is not stored, if the communication with OSS-ECU cannot be established
for 2500 ms or more, the combination meter determines that a problem has occurred.
PROBABLE CAUSES
Malfunction of CAN bus line
Malfunction of the OSS-ECU
Malfunction of the combination meter
DIAGNOSIS 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 normal?
Go to Step 2.
Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting ).
Repair the CAN bus line and go to Step 6.
STEP 2. M.U.T.-III other system diagnosis code
Check if diagnosis code is set to the OSS-ECU.
Q.
Is the diagnosis code set?
Troubleshoot the OSS-ECU (Refer to GROUP 42B - 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.
ETACS-ECU
Code No.U1000: OSS CAN timeout
Q.
Is the diagnosis code set?
Go to Step 4.
Go to Step 5.
STEP 4. 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)On completion, check that the diagnosis code is not reset.
Q.
Is the diagnosis code set?
Replace OSS-ECU and then go to Step 6.
A poor connection, open circuit or other intermittent malfunction is present in
the CAN bus lines between the OSS-ECU and the combination meter (Refer to GROUP 00 - How
to use troubleshooting/Inspection Service Points ).
STEP 5. 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)On completion, check that the diagnosis code is not reset.
Q.
Is the diagnosis code set?
Replace combination meter and then go to Step 6.
A poor connection, open circuit or other intermittent malfunction is present in
the CAN bus lines between the OSS-ECU and the combination meter (Refer to GROUP 00 - How
to use troubleshooting/Inspection Service Points ).
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)On completion, check that the diagnosis code is not reset.
Repair the CAN bus line (Refer to GROUP 54C - Troubleshooting 
).
Repair the CAN bus line and go to Step 6.