VARIABLE GEAR RATIO STEERING SYSTEM, Diagnostic DTC:C15C7/78, C15C8/79

DTC Code DTC Name
C15C7/78 DC Motor Power Source Voltage Malfunction
C15C8/79 Power Supply Relay Failure

DESCRIPTION

The steering control ECU monitors PIG (motor power source voltage) and detects a malfunction in the power supply relay (located inside the steering control ECU).

If the steering control ECU detects a malfunction, it will turn on the master warning light, store these DTCs, and stop VGRS operation.

DTC Code DTC Detection Condition Trouble Area
C15C7/78 The steering control ECU detects that the IG terminal voltage is between 9 and 16 V, and the PIG terminal voltage is below 7 V or higher than 18.5 V for 2.4 seconds.

  • Harness or connector

  • Steering control ECU
C15C8/79 The steering control ECU detects a malfunction in the power source relay or an open circuit.

  • Harness or connector

  • Steering control ECU

WIRING DIAGRAM

A01X22DE09
*1 from Battery
*2 Steering Control ECU

CAUTION / NOTICE / HINT

Tech Tips

The fault may be intermittent. Check the harnesses and connectors thoroughly and retest.

PROCEDURE


  1. CHECK HARNESS AND CONNECTOR (POWER SOURCE CIRCUIT)


    1. Record and clear the DTCs Click here.

    2. A01X6P3E03
      *1 Component with harness connected: (Steering Control ECU)

      Measure the resistance and voltage according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      E77-7 (PGND) - Body ground Always Below 1 Ω
      E78-8 (PGD2) - Body ground
      Standard Voltage
      Tester Connection Condition Specified Condition
      E77-8 (PIG) - Body ground Always 11 to 14 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

    OK

  2. RECONFIRM DTC OUTPUT


    1. Check for DTCs Click here.

      Result
      Result Proceed to
      C15C7/78 or C15C8/79 is not output A
      C15C7/78 or C15C8/79 is output (for LHD) B
      C15C7/78 or C15C8/79 is output (for RHD) C

    A

    USE SIMULATION METHOD TO CHECK Click here

    B

    REPLACE STEERING CONTROL ECU Click here

    C

    REPLACE STEERING CONTROL ECU Click here