Keep Those Trannys Rolling - July - 2018

Diagnosing Ford’s Intelligent AWD System

Understanding and diagnosing today’s domestic all-wheel drive systems can be quite intimidating. They’re designed to operate in conjunction with many of today’s on-board systems, such as the engine performance system, the transmission control system, and the antilock brake system, which may also include the vehicle ride and stability control systems.

In this issue of Keep those Trannys Rolling, we’ll look at the diagnostic routines needed to keep Ford’s Intelligent AWD systems rolling down the road.

WHAT IS AN INTELLIGENT AWD SYSTEM?

Ford’s new all-wheel drive systems are referred to as Intelligent All-Wheel Drive systems. These all-wheel drive systems are always active and require no input from the driver; there’s no mode-select switch.

These systems combine transparent, all-surface operation and are capable of handling all road conditions, including street and highway driving, and off-road and winter driving.

HOW DOES THE INTELLIGENT AWD SYSTEM OPERATE?

The intelligent AWD system continuously monitors vehicle conditions and automatically adjusts the torque distribution between the front and rear wheels.

During normal operation, most of the torque from the transmission is sent to the front wheels. If the computer detects wheel slip between the front and rear wheels, or if you operate the vehicle under heavy throttle, the Intelligent AWD system will increase the torque to the rear wheels to prevent or control wheel slip.

DIAGNOSING FORD’S INTELLIGENT AWD SYSTEMS

Diagnosing Ford’s Intelligent AWD system is pretty straightforward: Simply connect a compatible scan tool to the DLC and check for codes in the PCM, TCM, and the ABS control module. Document all codes you receive from each of these modules.

Before starting your diagnosis, be sure to correct all codes in the other modules. PCM and ABS problems can interfere with the all-wheel drive system operation.

After you’ve corrected all codes in the other modules, access the DEM (differential electronic module) or the 4WDCM (4wd control module) and retrieve codes from the AWD system.

DEM AND 4WDCM CODE DEFINITIONS

See figure 1 for a list of codes you might find in the DEM or 4WDCM.

DEM CODE DIAGNOSTIC ROUTINES

P0562 — System voltage is low. Check battery and charging system voltage. Verify all power and ground voltages are correct at the DEM connector. If system voltage is within specification, replace the DEM.

P0563 — System voltage is high. Check battery and charging system voltage. Verify all power and ground voltages are correct at the DEM connector. If system voltage is within specification, replace the DEM.

P0602 — PCM programming error. Attempt to clear code P0602. If it returns, verify all power and ground voltages are correct at the DEM connector. If voltages are within specification, replace the DEM.

P0606 — ECU short or open circuit. Attempt to clear code P0606. If it returns, verify all power and ground voltages are correct at the DEM connector. If voltages are within specification, replace the DEM.

P0932 — Hydraulic pressure sensor circuit. Check rear axle oil temperature sensor circuit. If the circuit is okay, suspect a faulty rear axle oil temperature sensor. Replace the rear axle oil temperature sensor.

P0937 — Hydraulic oil temperature sensor circuit. Check rear axle oil temperature sensor circuit. If the circuit is okay, suspect a faulty rear axle oil temperature sensor. Replace the rear axle oil temperature sensor.

P0939 — Hydraulic oil temperature sensor circuit low input. Check rear axle oil temperature sensor circuit. If the circuit is okay, suspect a faulty rear axle oil temperature sensor. Replace the rear axle oil temperature sensor.

P0940 — Hydraulic oil temperature sensor circuit high input. Check rear axle oil temperature sensor circuit. If the circuit is okay, suspect a faulty rear axle oil temperature sensor. Replace the rear axle oil temperature sensor.

P0960 — Pressure control solenoid A circuit open. Check ABS wheel sensor PIDs to verify that the ABS module is transmitting the correct wheel speed to the DEM. Check for fluid leaks from the active on-demand coupler. If you don’t find any leaks, check the PCS A circuit. If the PCS A circuit is okay, replace the DEM.

P0961 — Pressure control solenoid A circuit performance. Check ABS wheel sensor data to verify that the ABS module is transmitting the correct wheel speed to the DEM. Check for fluid leaks from the active on-demand coupler. If you don’t find any leaks, check the PCS A circuit. If the PCS A circuit is okay, replace the DEM.

P0961 — Pressure control solenoid A circuit low. Check ABS wheel sensor data to verify that the ABS module is transmitting the correct wheel speed to the DEM. Check for fluid leaks from the active on-demand coupler. If you don’t find any leaks, check the PCS A circuit. If the PCS A circuit is okay, replace the DEM.

P1889 — Oil pressure pump performance. Install a new, active, on-demand coupler oil pump. If the code returns, install updated DEM kit #4C016, available at your local Ford dealership.

U0001 — High-speed CAN communication error. Check high speed CAN bus system wiring and connection. Repair as needed.

U0121 — Loss of communication with ABS module. Check CAN communication system. Check wiring and connections. Check ABS module power and grounds. If CAN system and ABS module power and grounds are okay, suspect a faulty ABS module.

U2050 — No valid application for DEM. Reconfigure the DEM using as-built data.

4WDCM CODE DIAGNOSTIC ROUTINES

B1317 — Battery voltage high. Check battery and charging system operation. Repair as needed.

B1318 — Battery voltage low. Check battery and charging system operation. Repair as needed.

B1342 — ECU defective. Attempt to clear code B1342. If the code returns, check the 4WDCM power and ground circuits. If power and ground circuits are good, replace the 4WDCM.

P1635 — Tire or axle out of acceptable range. Check for correct tire sizes. Check tire pressure. Check ABS system for wheel speed sensor fault. If wheel speed sensor fault exists, repair as needed.

P1824 — 4WD clutch relay circuit failure. Check 4WD clutch relay circuit. Check active, on-demand coupler circuits. If the coupler circuits check out okay, suspect a faulty active, on-demand coupler or a faulty 4WDCM.

P1825 — 4WD clutch relay circuit open. Check 4WD clutch relay circuit. Check active, on-demand coupler circuits. If the coupler circuits check out okay, suspect a faulty active, on-demand coupler or a faulty 4WDCM.

U0100 — Loss of communication with PCM. Check the CAN communication system. Check PCM power and ground circuits. If the CAN communication system and the PCM power and ground circuits are okay, suspect a faulty PCM.

U0121 — Loss of communication with ABS. Check the CAN communication system. Check ABS module power and ground circuits. If the CAN communication system and the ABS module power and ground circuits are okay, suspect a faulty ABS module.

U0401 — Invalid data received from PCM. Check data coming from the PCM for being out of range. Repair as needed.

U0415 — Invalid data received from ABS module. Check data coming from ABS module for being out of range. Repair as needed.

U1900 — CAN communication bus fault. Check CAN communication system, wiring, and connections. Repair as needed.

Refer to the appropriate service manual for your specific vehicle’s diagnostic routines.

Well, there you have it: a quick look at the diagnostic routines needed to keep these intelligent AWD systems rolling down the road.

With a basic understanding of how Ford’s Intelligent AWD System operates and interacts with other onboard systems, you should have no problem diagnosing and repairing them.

And with a better understanding of how these AWD systems operate, you should have no problem keeping those trannys rolling.