EASY AND SMOOTH START SYSTEM, Diagnostic DTC:C1390/42

DTC Code DTC Name
C1390/42 Battery Power Supply Voltage

DESCRIPTION

If a malfunction is detected in the power supply circuit, the skid control ECU stores this DTC.

This DTC is stored when the BAT terminal voltage deviates from the DTC detection condition due to a malfunction in the power supply or charging circuit such as the battery or alternator circuit, etc.

This DTC is cleared when the BAT terminal voltage returns to normal.

DTC Code DTC Detection Condition Trouble Area
C1390/42 With the engine running, the BAT terminal voltage is 19 V or less for 10 seconds or more.

  • ECU-B fuse

  • Open or short in wire harness

  • Improperly connected connector or corroded terminal

  • Power source circuit

  • Charging system

  • Skid control ECU

  • Battery

WIRING DIAGRAM

A01CHPSE01

INSPECTION PROCEDURE

PROCEDURE


  1. INSPECT ECU-B FUSE


    1. Remove the ECU-B fuse from the No. 2 relay block.

    2. A01CHV0E04
      Text in Illustration
      *1 No. 2 relay block
      *2 ECU-B Fuse

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      ECU-B (10A) fuse Always Below 1 Ω

    NG

    REPLACE ECU-B FUSE

    OK

  2. CHECK BATTERY


    1. Install the ECU-B fuse.

    2. Check the battery voltage.

      Standard Voltage
      20 to 32 V

    NG

    CHECK OR REPLACE CHARGING SYSTEM OR BATTERY (N04C-UH) Click here

    OK

  3. INSPECT SKID CONTROL ECU (BAT CIRCUIT)


    1. Disconnect the skid control ECU connector.

    2. A01CHPQE01
      Text in Illustration
      *1

      Rear view of wire harness connector

      (to Skid Control ECU)

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

      Standard Voltage
      Tester Connection Condition Specified Condition
      S13-3 (BAT) - Body ground Always 20 to 32 V

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (BAT CIRCUIT)

    OK

  4. INSPECT SKID CONTROL ECU (GND CIRCUIT)


    1. Turn the ignition switch off.

    2. Disconnect the skid control ECU connectors.

    3. A01CHTLE01
      Text in Illustration
      *1

      Rear view of wire harness connector

      (to Skid Control ECU)

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

      Standard Resistance
      Tester Connection Condition Specified Condition
      S14-2 (GND1) - Body ground Always Below 1 Ω
      S14-3 (GND2) - Body ground Always Below 1 Ω
      S11-15 (GND3) - Body ground Always Below 1 Ω
      S11-14 (GND4) - Body ground Always Below 1 Ω

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)

    OK

  5. RECONFIRM DTC


    1. Reconnect the skid control ECU connectors.

    2. Clear the DTCs Click here.

    3. Perform a road test.

    4. Check if the same DTC is recorded Click here.

      Result
      Result Proceed to
      DTC (C1390/42) is not output A
      DTC (C1390/42) is output B

      Tech Tips

      If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step Click here.


    B

    REPLACE SKID CONTROL ECU

    A

    CHECK FOR INTERMITTENT PROBLEMS Click here