RX400h · Service Manual BRAKE

C1378/44

Diagnostic trouble codes

DESCRIPTION

The brake control power supply assembly (capacitor) provides auxiliary power for brake control when an auxiliary battery (12 V) voltage drops.
The FAIL and ENA lines are placed between the skid control ECU and the brake control power supply assembly.
Signals indicating that the brake control power supply is in auxiliary mode are sent to the skid control ECU through the FAIL line.
Charge permit prohibition signals are sent to the brake control power supply through the ENA line.
DTC No.
 INF Code
 DTC Detecting Condition
 Trouble Area
C1378/44
 112
  1. Open or short in FAIL line.
  2. Malfunction inside the power back up unit.
  1. Harness and connector
  2. Brake control power supply
  3. Skid control ECU

WIRING DIAGRAM

C112005E03

INSPECTION PROCEDURE

NOTICE:
When replacing the skid control ECU, perform initialization of linear solenoid valve and calibration (Click here).


1. INSPECT BRAKE CONTROL POWER SUPPLY (IG1 TERMINAL)

  1. F100411E08
    Measure the voltage according to the value(s) in the table below.

    HINT:
    Measure the voltage from the back side of the connector with the connector connected to the skid control ECU.

    Voltage:
    Tester Connection
    		 Condition
    		 Specified Condition
    B22-5 (IG1) - Body ground
    		 Ignition switch ON
    		 10 to 14 V



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


2. CHECK HARNESS AND CONNECTOR (BETWEEN SKID CONTROL ECU AND BRAKE CONTROL POWER SUPPLY)

  1. C112026E03
    Turn the ignition switch off.

  1. Disconnect the skid control ECU connector and brake control power supply connector.

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

    Resistance:
    Tester Connection
    		 Specified Condition
    S40-30 (ENA) - B22-12 (ENA)
    		 Below 1 Ω
    S40-20 (FAIL) - B22-13 (FAIL)
    		 Below 1 Ω

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

    Resistance:
    Tester Connection
    		 Specified Condition
    S40-30 (ENA) - Body ground
    		 10 kΩ or higher
    S40-20 (FAIL) - Body ground
    		 10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


3. CHECK FREEZE FRAME DATA

  1. Check the INF code from the FREEZE FRAME DATA memorized when the DTC (C1378/44) is stored (Click here).

    Result:
    Condition
    		 Proceed To
    INF codes are not output
    		 A
    INF code (112) is output
    		 B



B
REPLACE BRAKE CONTROL POWER SUPPLY
A

REPLACE SKID CONTROL ECU


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