If the EPS-ECU
sets the diagnosis code No. U1100, diagnose the CAN bus lines. If there is any fault in the
CAN bus lines, an incorrect diagnosis code may be set.
Before replacing ECU, ensure that the communication circuit is normal.
TROUBLE JUDGEMENT
EPS-ECU receives the READY signal from the EV-ECU via CAN bus lines. If the EPS-ECU cannot receive
the READY signal from the EV-ECU, the diagnosis code No. U1100 will be set.
COMMENT ON TROUBLE SYMPTOM
Current trouble
The wiring harness or connector in the CAN bus lines between the EPS-ECU and EV-ECU,
the power supply system of the EV-ECU, or the EPS-ECU itself may be faulty.
Past trouble
If the diagnosis code No. U1100 is stored as a historic trouble, carry out the diagnosis
with particular emphasis on the wiring harness and connector in the CAN bus lines between the EPS-ECU
and EV-ECU as well as on the power supply system of the EV-ECU. For diagnosis procedures, refer
to "How to treat past trouble" (Refer to GROUP 00 - How to Use Troubleshooting/Inspection
Service Points ).
note
In case of a historic trouble, the M.U.T.-III CAN bus diagnosis cannot find the problem
even when there is an abnormality in the CAN bus. In this case, be sure to diagnose the CAN
bus lines in the same manner as for "How to Cope with Intermittent Malfunction" (refer to GROUP
00 - How to Use Troubleshooting/Inspection Service Points ).
You can narrow down the possible cause of the trouble by referring to the diagnosis code, which
is set regarding the CAN communication-linked ECUs (refer to GROUP 54C - Explanation
About the M.U.T.-III CAN Bus Diagnostics ).
PROBABLE CAUSES
Defective harness wire(s) or connector(s)
Malfunction of the EV-ECU
Malfunction of the EPS-ECU
DIAGNOSIS PROCEDURE
STEP 1. M.U.T.-III CAN bus diagnosis
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 lines. (Refer to GROUP 54C, Troubleshooting .
) After repairing the CAN bus lines, go to STEP 2.
STEP 2. Use M.U.T.-III to confirm a diagnosis code of other systems.
Check if the diagnosis code is set to the EV-ECU.
Q.
Is the diagnosis code set?
Perform the troubleshooting for the EV-ECU (refer to group 54D - EV-ECU - Diagnosis
Code Chart ).
Go to Step 3.
STEP 3. Diagnosis code recheck
Recheck if the diagnosis code is set.
(1)Turn the electric motor switch to the "LOCK" (OFF) → "ON" position.
(2)Start the electric motor unit.
(3)Check if the diagnosis code No. U1100 is set as a current trouble.
Q.
Is diagnosis code U1100 set?
Replace EPS-ECU.
Intermittent malfunction. (Refer to GROUP 00 - How to Cope with Intermittent
Malfunction .)
).
