Code No.C1521
Motor turning angle (output) Code No.C1522 Motor turning angle range
caution
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
Power is supplied to the resolver from the EPS-ECU.
FUNCTION
To output the voltage based on the motor rotation angle to the EPS-ECU, the voltage is
supplied to the resolver.
TROUBLE JUDGEMENT
Check Conditions
The power supply circuit system diagnosis code (No. C1540, C1541) is not set.
Judgement Criterion
The resolver input voltage or the resolver output voltage does not meet a predetermined
voltage stored in the microcomputer, and the microcomputer determines that there is a problem
in the resolver system.
Fail Safe, Back Up Function
The EPS-ECU stops the motor control and illuminates the electric power steering
warning display, then sets the diagnosis code No. C1521 and C1522.
PROBABLE CAUSES
Malfunction of CAN bus line
Defective resolver of the steering column shaft assembly
Defective harness wire(s) or connector(s)
Short or open circuit between the EPS-ECU and the resolver or loose connector
contact
Malfunction of the EPS-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 C1521 or C1522 set?
Go to Step 3.
This diagnosis is complete.
STEP 3. Check of short to power supply, short to earth, and open circuit
in S1+, S3-, S2+, S4-, R1+, R2- line between
EPS-ECU connector and resolver
Q.
Is the check result normal?
Go to Step 4.
Go to Step 6.
STEP 4. M.U.T.-III data list
Check the following data list .
Item No. 04: Motor current
Item No. 05: Motor current (target)
Item No. 17: Motor electric angle
Item No. 18: Motor speed
Q.
Is the check result normal?
Go to Step 5.
Go to Step 7.
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.
(3)Check if the diagnosis code is set.
Q.
Is the diagnosis codes C1521 or C1522 set?
Replace the EPS-ECU (Refer to ).Then go to
Step 6.
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent
Malfunctions ).
STEP 6. 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 C1521 or C1522 set?
Replace the steering column shaft assembly (Refer to ).Then
go to Step 7.
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent
Malfunctions ).
STEP 7. 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.