Code No.C1520 Motor turning angle (input)
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 Nos. C1520, 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 C1520, C1521 or C1522 set?
Go to Step 3.
This diagnosis is complete.

STEP 3. Check the following connector.
Check the connectors below for improper engagement, terminal damage or terminal drawn in the connector case.

  • C-221-1 EPS-ECU connector

Q. Is the connectors and terminals in good condition?
Go to Step 4.
Go to Step 7.

STEP 4. Wiring harness check
(1)Check the wiring harness between the C-221-1 EPS-ECU connector terminals No.21,No.22,No.23,No.25,No.27 or No.28 and the resolver for damage or other problem.
(2)Check the wiring harness between the C-222 EPS-ECU connector terminal No.12 and the body earth point for damage or other problem.

Q. Is the wiring harness in good condition?
Go to Step 5.
Go to Step 7.

STEP 5. 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 8.
Go to Step 6.

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 C1520,C1521 or C1522 set?
Replace the EPS-ECU (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.
(3)Check if the diagnosis code is set.

Q. Is the diagnosis codes C1520,C1521 or C1522 set?
Replace the steering column shaft assembly (Refer to ).Then go to Step 8.
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunctions ).

STEP 8. 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 C1520,C1521 or C1522 set?
Return to Step 1.
This diagnosis is complete.