C1296

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

DTC 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 wheel 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 Reading and Clearing Diagnostic Trouble Codes.
(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 (w/o VDIM).
Result:






B -- REPAIR CIRCUITS INDICATED BY OUTPUT DTCS (BRAKE CONTROL SYSTEM)
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 Scan Tool Testing and Procedures.
(d) Check that the speed values detected at all four wheels displayed on the Techstream are the same when driving the vehicle.

HINT: Drive the vehicle straight ahead.

DATA LIST: 4WD





OK:
The speed of all four wheels displayed on the Techstream should match.
NG -- CHECK HARNESS AND CONNECTOR (4WD CONTROL ECU TO SKID CONTROL ECU)
OK -- Continue to next step.
3. 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 12 mph (20 km/h) or more and check if the same DTC is output.
Result:






B -- CHECK INTERMITTENT PROBLEMS
A -- REPLACE 4WD CONTROL ECU
4. 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.
Standard resistance:






NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
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 -- REPLACE BRAKE CONTROL ACTUATOR ASSEMBLY (SKID CONTROL ECU)
A -- REPLACE 4WD CONTROL ECU