This is part of our series of blog posts designed to help customers understand their vehicle better. Please keep in mind these are general descriptions of how these modules function. There are differences in many years and models, but generally the principles remain the same.
The Differential Electronic Module (DEM) is a vital part of modern all-wheel-drive (AWD) systems, especially in vehicles like Volvos, Land Rovers, and some Ford models. The DEM controls the engagement of the rear differential, ensuring optimal traction and vehicle stability under varying road conditions. When this module begins to fail, it can lead to performance issues and even disable the AWD system entirely.
Below, we break down the most common symptoms of a faulty DEM, some diagnostic trouble codes (DTCs) you might see, and how XeMODeX’s proven repair solutions can get you back on the road quickly.
Common Symptoms of a Faulty DEM
1 All-Wheel Drive Disabled Message
One of the most frequent symptoms is a warning on the instrument cluster stating, “All Wheel Drive Disabled” or “AWD Service Required.” This indicates the system has shut down the rear differential due to an internal fault.
2 Loss of Rear-Wheel Power
If the DEM fails, the rear differential may not engage properly, causing the vehicle to operate in front-wheel drive only. This can affect traction, especially in snow or off-road conditions.
3 Traction Control Light or ABS Warning
Since the DEM works in coordination with the vehicle’s ABS and traction control systems, faults in the DEM can trigger these warning lights.
4 Poor Handling or Uneven Tire Wear
Without proper AWD function, power delivery may become unbalanced, leading to uneven tire wear and degraded handling.
5 Communication Issues on Diagnostic Scan
A faulty DEM may not respond during diagnostic scans. This “no communication” issue is a strong sign of internal failure.
Common Diagnostic Trouble Codes (DTCs)
When scanned with a diagnostic tool, a faulty DEM may post one or more of the following codes:
- DEM-0006 – Pump activation too frequent
- DEM-0007 – Pump faulty signal
- DEM-0008 – Pressure too low
- DEM-0009 – Pressure too high
- DEM-0001 to DEM-0010 – General internal DEM errors
- U0122 – Lost communication with vehicle dynamics control module
- CEM-1A64 – Communication with DEM control module, signal missing
These codes typically indicate issues with internal circuitry, pump control, or CAN communication—all signs that the module needs professional attention.
XeMODeX: Trusted DEM Repairs for Over a Decade
At XeMODeX, we’ve been repairing Differential Electronic Modules for over 15 years. We don’t just replace components—we dig deep into the root cause of failure and rebuild the module using robust, long-lasting solutions. Each DEM repair includes:
- Complete testing of all circuits
- Replacement of faulty internal components
- Bench-testing under simulated real-world conditions
- Updated firmware when applicable
Final Thoughts
If you’re seeing AWD-related warning messages or experiencing traction issues, your DEM could be the culprit. Ignoring the issue may lead to more costly drivetrain repairs in the future.
Don’t wait—contact XeMODeX today and trust the experts who have been leading the way in module diagnostics and repair for nearly two decades.
Visit www.xemodex.com to see our DEM repair service, or our other products and services.
