DTC C1299/99 Cancellation of 4WD Control: Description

If wheel slip continues, differential control will be disabled when the torque-distribution ratio of the differential clutch exceeds the set value and a malfunction in the output of the wheel speed sensors, etc. occurs.
If a difference in diameter between the front and rear wheels is determined, differential control will be disabled.

DTC C1299/99 TROUBLE DETECTION REFERENCE

DTC No.	DTC Detecting Condition	Trouble Area
C1299/99	When either of the following are detected: The torque-distribution ratio of the differential clutch exceeds the set value. The vehicle is driven with tires different in size between the front and rear.	Tire size 4WD control ECU

HINT:

Check the condition of each related circuit connector before troubleshooting (See HOW TO TROUBLESHOOT ECU CONTROLLED SYSTEMS ).