If
there is any problem in the CAN bus lines, an incorrect diagnosis code may be set. Prior to
this diagnosis, diagnose the CAN bus lines (Refer to GROUP 54C, CAN Bus Diagnostics Table).
Whenever ECU is replaced, ensure that the CAN bus lines are normal.
OPERATION
An additional torque signal is sent from the 4WD-ECU
to the EPS-ECU.
FUNCTION
The additional torque signal is sent to the EPS-ECU
in order to control the motor.
TROUBLE JUDGEMENT
Check Conditions
The power supply circuit system diagnosis code (No. C1540, C1541) is not set.
The 4WD circuit system diagnosis code is not set.
Judgement Criterion
If the microcomputer receives abnormal additional torque signal from the 4WD-ECU
consecutively twice, it determines that the 4WD system is defective.
Fail Safe, Back Up Function
The EPS-ECU stores diagnosis code No. C1566.
PROBABLE CAUSES
Malfunction of CAN bus line
Malfunction of the EPS-ECU
Malfunction of the 4WD-ECU
DIAGNOSIS PROCEDURE
STEP 1. M.U.T.-III CAN bus diagnostics
Use M.U.T.-III to diagnose the CAN bus lines.
Q.
Is the check result normal?
Go to Step 3
Repair the CAN bus lines (Refer to GROUP 54C - CAN Bus Diagnostics Table ).
On completion, go to Step 2.
STEP 2. Diagnosis code recheck after resetting CAN bus lines
(1)Erase the diagnosis code.
(2)Turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.
(3)Check if the diagnosis code is set.
Q.
Is the diagnosis codes C1566 set?
Go to Step 3
This diagnosis is complete.
STEP 3. M.U.T.-III data list
Check the following service data .
Item No. 09: Add torque indication status
Q.
Is the check result normal?
Go to Step 5
Perform troubleshooting for 4WD-ECU (Refer to GROUP 27C - Troubleshooting/Inspection
Chart for Diagnosis code . Then go to Step 4.
STEP 4. Check whether the diagnosis code is reset
(1)Erase the diagnosis code.
(2)Turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.
(3)Check if the diagnosis code is set.
Q.
Is the diagnosis codes C1566 set?
Replace the EPS-ECU (Refer to ). Then go to
Step 5.
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent
Malfunction ).
STEP 5. Check whether the diagnosis code is reset.
(1)Erase the diagnosis code.
(2)Turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.