Open in IG1 / IG2 Power Source Circuit - Electronically Controlled Brake System

BRAKE CONTROL: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: C1241/41,C1242/42: Low Battery Positive Voltage

DTC C1241/41 - Low Battery Positive Voltage

DTC C1242/42 - Open in IG1 / IG2 Power Source Circuit

DESCRIPTION

These codes are memorized when the power source voltage for the skid control ECU drops or the voltage for the main relay 1 and main relay 2 operation drops.
Codes may be memorized when the voltage of the auxiliary battery temporarily drops.
When the power source voltage is too high, the skid control ECU stops functioning and outputs no DTCs, and the ABS and BRAKE warning lights remain on.
HINT: DTC C1256/57 (accumulator low voltage malfunction) may be memorized if the power source voltage drops.





WIRING DIAGRAM













INSPECTION PROCEDURE
NOTICE: When replacing the skid control ECU, perform initialization of linear solenoid valve and calibration Initialization.

PROCEDURE

1. CHECK HYBRID CONTROL SYSTEM
(a) Check if the hybrid control system DTC is output Hybrid Control System.
Result:






B -- INSPECT HYBRID CONTROL SYSTEM
A -- Continue to next step.
2. CHECK AUXILIARY BATTERY
(a) Check the auxiliary battery voltage.
Standard voltage:
11 to 14 V
NG -- CHARGE OR REPLACE AUXILIARY BATTERY
OK -- Continue to next step.
3. INSPECT SKID CONTROL ECU (IG AND +BI TERMINAL)




(a) Disconnect the skid control ECU connectors.
(b) Measure the voltage according to the value(s) in the table below.
Standard voltage:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (IG OR +BI CIRCUIT)
OK -- Continue to next step.
4. INSPECT SKID CONTROL ECU (GND TERMINAL)




(a) Disconnect the skid control ECU connector.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)
OK -- Continue to next step.
5. INSPECT SKID CONTROL ECU (RELAY TERMINAL)




(a) Reconnect the skid control ECU connectors.
(b) Turn the power switch on (IG).
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:






Result:






C -- REPAIR OR REPLACE HARNESS OR CONNECTOR (RELAY CIRCUIT)
B -- REPLACE SKID CONTROL ECU
A -- Continue to next step.
6. RECONFIRM DTC
(a) Turn the power switch off.
(b) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.
(c) Turn the power switch on (IG).
(d) Check if the same DTC is recorded Reading and Clearing Diagnostic Trouble Codes.
Result:






B -- REPLACE SKID CONTROL ECU
A -- CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION)