Electronically Controlled Brake System

BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: C1241/41, C1242/42: Low Battery Positive Voltage
C1242/42 - Open in IG1 / IG2 Power Source Circuit

DESCRIPTION

If a malfunction is detected in the power supply circuit, the skid control ECU power source voltage drops, or there is insufficient voltage to operate the ABS main relay, the skid control ECU will store these DTCs.

These DTCs may also be stored if the auxiliary battery voltage drops below 9.5 V.

HINT
DTC C1256/56 (Accumulator Low Pressure) may also be memorized if there is a drop in power source voltage.





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
When replacing the brake booster with master cylinder (skid control ECU), perform initialization and calibration of the linear solenoid valve Initialization.

PROCEDURE

1. CHECK SMART ACCESS SYSTEM WITH PUSH-BUTTON START (for Start Function)

(a) Check if the smart access system with push-button start (for start function) DTC is output Smart Access System With Push-Button Start (For Start Function).

Result:





B -- INSPECT SMART ACCESS SYSTEM WITH PUSH-BUTTON START (for Start Function) Smart Access System With Push-Button Start (For Start Function)
A -- Continue to next step.

2. CHECK HYBRID CONTROL SYSTEM

(a) Check if the hybrid control system DTC is output Hybrid Control System.

Result:





B -- INSPECT HYBRID CONTROL SYSTEM How to Proceed With Troubleshooting
A -- Continue to next step.

3. CHECK DTC

(a) Check that no main relay DTC is output Reading and Clearing Diagnostic Trouble Codes.

Result:





B -- REPAIR CIRCUITS INDICATED BY OUTPUT DTCS Electronically Controlled Brake System
A -- Continue to next step.

4. 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.

5. INSPECT SKID CONTROL ECU (POWER SOURCE TERMINAL)

(a) Make sure that there is no looseness at the locking part and the connecting part of the connector.





(b) Disconnect the skid control ECU connector.

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

Standard Voltage:





Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (POWER SOURCE CIRCUIT)
OK -- Continue to next step.

6. INSPECT SKID CONTROL ECU (GND TERMINAL)

(a) Turn the power switch off.





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

Standard Resistance:





Text in Illustration





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (GND CIRCUIT)
OK -- Continue to next step.

7. RECONFIRM DTC

(a) Reconnect the skid control ECU connector.

(b) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.

(c) Turn the power switch on (READY).

(d) Perform a road test.

(e) Check if the same DTC is recorded Reading and Clearing Diagnostic Trouble Codes.

Result:





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

B -- REPLACE BRAKE BOOSTER WITH MASTER CYLINDER Removal

A -- CHECK FOR INTERMITTENT PROBLEMS How To Proceed With Troubleshooting