If the EPS-ECU sets the diagnosis
code No. C1522, 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.
DIAGNOSIS CODE SET CONDITIONS
The diagnosis code No. C1522 is set when the system receives an abnormal signal from the
EV-ECU, and the microprocessor determines that a problem has occurred to the system.
CRITERIA FOR JUDGING MALFUNCTION
An abnormality is judged if the READY signal from EV-ECU is not sent to EPS-ECU after
the electric motor unit is started.
PROBABLE CAUSES
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. C1522 is set as a current trouble.
Q.
Is diagnosis code C1522 set?
Replace EPS-ECU.
Intermittent malfunction. (Refer to GROUP 00 - How to Cope with Intermittent
Malfunction .)
Go to Step 2.
Repair the CAN bus lines. (Refer to GROUP 54C, Troubleshooting 
.
) After repairing the CAN bus lines, go to STEP 2.