C1296

UF1AE TRANSFER: FOUR WHEEL DRIVE CONTROL SYSTEM: C1296/96: ABS Malfunction
C1296/96 - ABS Malfunction

DESCRIPTION

If a malfunction in the speed sensor signal circuit occurs, the 4WD control ECU will output this DTC. When slip is detected based on signals sent from the 4 vehicle speed sensors, the 4WD control ECU controls torque distribution between front and rear wheels according to the amount of slip.





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 .

(b) Start the engine.

(c) Drive the vehicle, accelerating to a speed of 12 mph (20 km/h) or more and check if the speed sensor DTC (brake control system DTC) is output Vehicle Stability Control System.

Result:





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

2. READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Start the engine.

(c) Select the "Data List" on the Techstream .

(d) Check that the speed values detected at all four wheels displayed on the Techstream are the same when driving the vehicle.

DATA LIST: (Absorber Control ECU)





OK:

The same vehicle speed detected at all four wheels must be indicated on the Techstream.

NG -- INSPECT 4WD CONTROL ECU (GND TERMINAL CONTINUITY)
OK -- Continue to next step.

3. RECONFIRM DTC

(a) Clear the DTC .

(b) Start the engine.

(c) Drive the vehicle, accelerating to a speed of 12 mph (20 km/h) or more and check if the same DTC is output.

Result:





B -- END

A -- REPLACE 4WD CONTROL ECU

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

(a) Disconnect the 4WD control ECU connector.





(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.

5. INSPECT 4WD CONTROL ECU (INPUT SIGNAL OF VEHICLE SPEED)

(a) Connect the 4WD control ECU connector.





(b) Connect the oscilloscope to the 4WD control ECU.

(c) Start the engine.

(d) Check the signal waveform when the vehicle is driving.





Standard:





HINT
As vehicle speed (wheel rotation speed) increases, the width of the waveform narrows.





Result:





B -- CHECK HARNESS AND CONNECTOR (4WD CONTROL ECU TO SKID CONTROL ECU)

A -- REPLACE 4WD CONTROL ECU

6. CHECK HARNESS AND CONNECTOR (4WD CONTROL ECU TO SKID CONTROL ECU)

(a) Disconnect the 4WD control ECU connector and skid control ECU connector.





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

Resistance:





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

7. RECONFIRM DTC

(a) Clear the DTC .

(b) Start the engine.

(c) Drive the vehicle, accelerating to a speed of 12 mph (20 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 -- CHECK BRAKE CONTROL SYSTEM