Normal Operation
WARNING: This page is about a different car, the 2008 Mercury Mariner and 2008 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
The four wheel drive (4WD) system continuously monitors vehicle conditions and automatically adjusts the torque distribution between the front and rear wheels. If wheel slip between the front and rear wheels is detected, or if the vehicle is under heavy acceleration, the 4WD system increases the torque to the rear wheels to prevent or control wheel slip.
- DTC P1635 Tire/Axle Out of Acceptable Range - When the 4X4 control module detects incorrect input values from ABS module (due to wheel size/tire mismatch greater than 5% ([minispare installed as a road wheel]), this DTC is set.
The 4X4 control module varies the torque sent to the rear wheels by sending a duty cycle to the active torque coupling located inside the rear axle. The 4X4 control module also provides the brake system with its current clutch duty cycle and whether or not the brake system may take command of the clutch duty cycle.
This pinpoint is intended to diagnose the following:
- Wheels/tires
- Wheel speed sensors
- ABS module
- 4X4 control module