From 08/2009

MF1A TRANSFER / 4WD / AWD: ACTIVE TORQUE CONTROL 4WD SYSTEM: C1241: Low Power Supply Voltage Malfunction
C1241 - Low Power Supply Voltage Malfunction

DESCRIPTION

If a malfunction in the power source circuit occurs, or a malfunction in communication with the skid control ECU or in a speed sensor occurs, the 4WD control ECU will prohibit operations by the fail-safe function.





WIRING DIAGRAM





INSPECTION PROCEDURE

NOTICE:
Inspect the fuses for circuits related to this system before performing the following inspection procedure.

HINT
Check the condition of each related circuit connector before troubleshooting Electronic Circuit Inspection Procedure.

PROCEDURE

1. CHECK FOR DTC (CAN COMMUNICATION SYSTEM AND BRAKE CONTROL SYSTEM)

(a) Check if the CAN communication system DTC is output Diagnosis System.

(b) Start the engine.

(c) Drive the vehicle, accelerate to a speed of 3 km/h (2 mph) or more, and check if the speed sensor DTC (brake control system DTC) is output Reading and Clearing Diagnostic Trouble Codes.

Result:





C -- REPAIR CIRCUIT INDICATOR BY OUTPUT CODE (BRAKE CONTROL SYSTEM) Vehicle Stability Control System

B -- REPAIR CIRCUIT INDICATOR BY OUTPUT CODE (CAN COMMUNICATION SYSTEM) CAN Communication System
A -- Continue to next step.

2. INSPECT BATTERY

(a) Check the battery voltage.

Standard Voltage:

11 to 14 V

NG -- INSPECT CHARGING SYSTEM
OK -- Continue to next step.

3. CHECK WIRE HARNESS (4WD CONTROL ECU - BATTERY)





(a) Disconnect the ECU connector.

(b) Measure the voltage of the wire harness side connector.

Standard Voltage:





Text in Illustration





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

4. CHECK WIRE HARNESS (4WD CONTROL ECU - BODY GROUND)





(a) Disconnect the ECU connector.

(b) Measure the resistance of the wire harness side connector.

Standard Resistance:





Text in Illustration





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) Start the engine.

(c) Drive the vehicle, accelerate to a speed of 3 km/h (2 mph or more, and check if the same DTC is output.

Result:





HINT
Reinstall the sensor, connectors, etc. and restore the vehicle to its prior condition before rechecking DTCs.

B -- CHECK INTERMITTENT PROBLEMS

A -- REPLACE 4WD ECU ASSEMBLY