Four Wheel Drive Control System

UF1AE TRANSFER: FOUR WHEEL DRIVE CONTROL SYSTEM: C1241/94: Low Power Supply Voltage
C1241/94 - Low Power Supply Voltage

DESCRIPTION

If a malfunction in the power source circuit occurs and, when 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

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

PROCEDURE

1. CHECK DTC

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

(b) Turn the engine switch on (IG) and check that no CAN communication system DTC is output.

(c) Start the engine.

(d) Drive the vehicle, accelerating to a speed of 2 mph (3 km/h) or more and check that no speed sensor DTC (brake control system DTC) is output Reading and Clearing Diagnostic Trouble Codes, and Vehicle Stability Control System).

Result:





C -- REPAIR CIRCUIT INDICATED BY OUTPUT CODE

B -- REPAIR CIRCUIT INDICATED BY OUTPUT CODE
A -- Continue to next step.

2. INSPECT FUSE (ECU-IG LH FUSE)

(a) Remove the ECU-IG LH fuse from the cowl side J/B LH.

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

Resistance:





HINT
Check for short in all harnesses and connectors connected to the ECU-IG LH fuse Electronic Circuit Inspection Procedure.

NG -- REPLACE ECU-IG LH FUSE
OK -- Continue to next step.

3. INSPECT BATTERY

(a) Check the battery voltage.

Voltage:

10 to 14 V

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

4. INSPECT 4WD CONTROL ECU (IG1 TERMINAL VOLTAGE)

(a) Disconnect the 4WD control ECU connector.





(b) Turn the engine switch on (IG).

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

Voltage:





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (IG1 CIRCUIT)
OK -- Continue to next step.

5. INSPECT 4WD CONTROL ECU (GND TERMINAL CONTINUITY)

(a) Turn the engine switch off.





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

Resistance:





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

6. RECONFIRM DTC

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

(b) Start the engine.

(c) Drive the vehicle, accelerating to a speed of 2 mph (3 km/h) 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 -- END

A -- REPLACE 4WD CONTROL ECU