C1242

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


DESCRIPTION

These codes are memorized when the power source voltage for the skid control ECU drops or the voltage for the ABS MAIN1 relay and ABS MAIN2 relay operation drops. The ABS MAIN1 relay and ABS MAIN2 relay are in the skid control ECU.

HINT
DTC C1256/57 (accumulator low pressure) may be memorized if the power source voltage drops.









WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
When replacing the skid control ECU, perform the following operations:

- Initialization of linear solenoid valve and calibration Initialization
- Yaw rate and acceleration sensor zero point calibration Calibration

PROCEDURE

1. INSPECT AUXILIARY BATTERY

(a) Check the auxiliary battery voltage.

Standard voltage:

11 to 14 V

NG -- RECHARGE OR REPLACE AUXILIARY BATTERY Service Precautions
OK -- Continue to next step.

2. CHECK DTC

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

(b) Turn the power switch OFF.

(c) Turn the power switch ON (IG).

(d) Check that the DTCs (electronically controlled brake system and hybrid control system) are recorded Reading and Clearing Diagnostic Trouble Codes.

Result





C -- REPAIR CIRCUIT INDICATED BY OUTPUT CODE Electronically Controlled Brake System

B -- GO TO HYBRID CONTROL SYSTEM (HOW TO PROCEED WITH TROUBLESHOOTING) How To Proceed With Troubleshooting
A -- Continue to next step.

3. CHECK TERMINAL VOLTAGE (IG1, IG2, +BI1, +BI2, +BI3, +BI4)

(a) Disconnect the A19 and A21 ECU connectors.





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

Standard voltage:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

4. CHECK HARNESS AND CONNECTOR (GND CIRCUIT)

(a) Disconnect the A19 and A21 ECU connectors.

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

Standard resistance:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

5. RECONFIRM DTC

(a) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.

(b) Turn the power switch ON (READY).

(c) After 2 minutes or more have elapsed, drive the vehicle 5 km/h (3 mph) or more for 20 seconds.

(d) Check if the same DTCs are recorded Reading and Clearing Diagnostic Trouble Codes.

Result





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

B -- REPLACE SKID CONTROL ECU Removal

A -- USE SIMULATION METHOD TO CHECK How To Proceed With Troubleshooting