C1377

BRAKE CONTROL: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: C1377/43: Capacitor Malfunction

DTC C1377/43 - Capacitor Malfunction

DESCRIPTION

The brake control power supply (capacitor) is used as auxiliary power for brake control when the auxiliary battery voltage is low.






WIRING DIAGRAM














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

PROCEDURE

1. CHECK FREEZE FRAME DATA
(a) Check the INF code from the Freeze Frame Data memorized when the DTC (C1377/43) is stored. Freeze Frame Data
Result:






C -- CHECK AUXILIARY BATTERY
B -- REPLACE BRAKE CONTROL POWER SUPPLY
A -- Continue to next step.
2. INSPECT ABS NO. 3 FUSE





(a) Remove the ABS NO. 3 fuse from the engine room relay block.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:






NG -- REPLACE ABS NO. 3 FUSE
OK -- Continue to next step.
3. INSPECT BRAKE CONTROL POWER SUPPLY (+BC TERMINAL)





(a) Install the ABS NO. 3 fuse.
(b) Make sure that there is no looseness at the locking part and the connecting part of the connector.
(c) Disconnect the brake control power supply connector.
(d) Measure the voltage according to the value(s) in the table below.
Standard voltage:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (+BC CIRCUIT)
OK -- Continue to next step.
4. INSPECT BRAKE CONTROL POWER SUPPLY (GND TERMINAL)





(a) 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 (+BI TERMINAL)
(a) Make sure that there is no looseness at the locking part and the connecting part of the connectors.





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






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (+BI CIRCUIT)
OK -- Continue to next step.
6. INSPECT SKID CONTROL ECU (RELAY INPUT)





(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:






NG -- REPLACE SKID CONTROL ECU
OK -- Continue to next step.
7. INSPECT BRAKE CONTROL POWER SUPPLY (OUT AND CTY+ TERMINAL)





(a) Reconnect the brake control power supply connector.
(b) Turn the power switch on (IG).
(c) Measure the voltage according to the value(s) in the table below.
HINT: Perform inspection while the brake pedal is not depressed.

Standard voltage:





(*1): For 5 seconds after the driver's door is opened.
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (OUT OR CTY+ CIRCUIT)
OK -- Continue to next step.
8. RECONFIRM DTC
(a) Turn the power switch off.
(b) Clear the DTCs.
(c) Turn the power switch on (IG).
(d) Check if the same DTC is recorded.
Result:






B -- REPLACE SKID CONTROL ECU
A -- CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION)
9. 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.
10. INSPECT BRAKE CONTROL POWER SUPPLY (+BC TERMINAL)
(a) Make sure that there is no looseness at the locking part and the connecting part of the connector.





(b) Disconnect the brake control power supply connector.
(c) Measure the voltage according to the value(s) in the table below.
Standard voltage:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (+BC CIRCUIT)
OK -- Continue to next step.
11. RECONFIRM DTC
(a) Clear the DTCs.
(b) Turn the power switch on (IG).
(c) Check if the same DTC is recorded.
Result:






B -- REPLACE BRAKE CONTROL POWER SUPPLY
A -- CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION)