Code No. C1531: Abnormal motor terminal voltage







caution
  • If the EPS-ECU sets the diagnosis code No. C1531, 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 motor terminal voltage does not meet a predetermined voltage stored in the microcomputer, and the microcomputer determines that there is a problem in the motor terminal voltage.
    • Criteria for judging malfunction
    • The terminal voltage in the motor left and right is less than 0.2 V or more than 8.5 V.

PROBABLE CAUSES



  • Defective harness wire(s) or connector(s)
  • Defective motor of the steering gear and linkage assembly
  • Malfunction of the EPS-ECU

DIAGNOSIS PROCEDURE

STEP 1. Connector check: B-114-1 EPS-ECU connector

Q. Is the check result normal?
Go to Step 2.
Repair the damaged connector.

STEP 2. Measure the resistance at B-114-1 EPS-ECU connector.
(1)Disconnect the connector and measure at the wiring harness side.
(2)Measure the resistance between B-114-1 EPS-ECU connector terminal No. 2 and the body earth.
OK: Continuity exists. (300 Ω or more)
(3)Measure the resistance between B-114-1 EPS-ECU connector terminal No. 1 and the body earth.
OK: Continuity exists. (300 Ω or more)

Q. Is the check result normal?
Go to Step 3.
Replace the steering gear & linkage assembly..

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. C1531 is set as a current trouble.

Q. Is diagnosis code C1531 set?
Replace EPS-ECU.
Intermittent malfunction. (Refer to GROUP 00 - How to Cope with Intermittent Malfunction .)