Code No.C1512 Torque sensor main/sub voltage


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 torque sensor from the EPS-ECU.

FUNCTION
The voltage based on the input torque is output to the EPS-ECU from the torque sensor main and torque sensor sub, and the sum of the torque sensor main output voltage and sub output voltage values are monitored for motor control.

TROUBLE JUDGEMENT
Check Conditions
    With the torque sensor power supply ON, 5 V is supplied to the torque sensor.
Judgement Criterion
    The sum of the torque sensor main output voltage and sub output voltage does not meet a predetermined value stored in the microcomputer, and the microcomputer determines that a problem has occurred in the mutual monitoring for the sensor main/sub systems.
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. C1512.

PROBABLE CAUSES

  • Malfunction of CAN bus line
  • Defective torque sensor of the steering column shaft assembly
  • Defective harness wire(s) or connector(s)

    • Short or open circuit between the EPS-ECU and the torque sensor 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 code C1512 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 and C-222 EPS-ECU connector
  • Intermediate connector of the wiring harness for steering column shaft assembly (connection and appearance checks only)

Q. Is the connectors and terminals in good condition?
Go to Step 4.
Go to Step 8.

STEP 4. Wiring harness check
(1)Check the wiring harness between the C-221-1 EPS-ECU connector terminal No.26 and the torque sensor main for damage or other problem.
(2)Check the wiring harness between the C-221-1 EPS-ECU connector terminal No.24 and the torque sensor sub for damage or other problem.

Q. Is the wiring harness in good condition?
Go to Step 5.
Go to Step 8.

STEP 5. Voltage measurement at the EPS-ECU connector
(1)The steering is in the neutral position.
(2) Measure the EPS-ECU voltage without disconnecting the connector (by backprobing).
(3)Turn the ignition switch from the "LOCK" (OFF) position to the "ON" position.
(4)Measure the voltage between the C-221-1 EPS-ECU connector terminal No.26 (for main system) and the C-222 EPS-ECU connector terminal No.12.
OK: 2.5 ± 0.05 V
(5)Measure the voltage between the C-221-1 EPS-ECU connector terminal No.24 (for sub system) and the C-222 EPS-ECU connector terminal No.12.
OK: 2.5 ± 0.05 V

Q. Is the check result normal?
Go to Step 6.
Go to Step 8.

STEP 6. M.U.T.-III data list
(1)The steering is in the neutral position.
(2)Check the following data list .

  • Item No. 01: Torque sensor (main)
  • Item No. 02: Torque sensor (sub)

Q. Is the check result normal?
Go to Step 9.
Go to Step 7.

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 code C1512 set?
Replace the EPS-ECU (Refer to ). Then go to Step 8.
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunctions ). Then go to Step 8.

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 code C1512 set?
Replace the steering column shaft assembly (Refer to ). Then go to Step 9.
Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunctions ).

STEP 9. 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 code C1512 set?
Return to Step 1.
This diagnosis is complete.