This post is part of our “Deep Delve” series, where we’ll focus on one part at a time. The goal of these posts is to provide our customers with the knowledge they need to make informed decisions about their vehicle. We can’t reveal all the knowledge we have about these parts, but hopefully the information below will help you find the issue in your vehicle.
What is a Central Electronic Module (CEM)?
A future blog post will delve deeper into the role of the Central Electronic Module (CEM), but in short, it functions as a “smart fuse box,” managing key electrical and communication systems. As one of your vehicle’s most critical modules, any CEM-related issues should be addressed promptly. These modules are prone to failure, and replacing them can be complex due to vehicle-specific programming requirements. Below, we’ll cover common faults, symptoms, and how XeMODeX offers reliable solutions.
This part is found on the following Volvo models:
- 2005 – 2009 Volvo S60
- 2005 – 2006 Volvo S80
- 2005 – 2007 Volvo V70
- 2005 – 2007 Volvo XC70
- 2005 – 2013 Volvo XC90
Common CEM Faults and Symptoms
Physical Damage:
- Water damage
- Burnt smell from the CEM
Network Communication Failures:
- Complete loss of communication
- Low-speed network failure: Instrument cluster, power windows, power seats, radio, and remote lock/unlock stop working
- High-speed network failure: No start, no communication with ECM, DEM, or TCM
Electrical and Functional Issues:
- Clicking sound behind the dash
- Lights staying on even after removing the key
- No communication with scan tool
- No LIN communication with the alternator
- Starter motor inoperative despite immobilizer approval
Lighting and Signal Malfunctions:
- Turn signals malfunctioning (only one side working or one side stuck on)
- Headlight issues: flickering, low/high beams or fog lights not working
- Brake light failure (left/right brake lights not working, but high-mounted brake light operational)
Horn and Wiper Problems:
- Horn either non-functional or stuck on continuously
- Windshield wipers not working, stuck on high speed, or operating erratically
- Windshield washer pump failure
Brake Control and Key Issues:
- No power at fuse 15, leading to no communication with the Brake Control Module (BCM)
- Keys not recognized by the vehicle
Common Diagnostic Codes Indicating CEM Failure.
Please note the presence of these codes (minus the internal fault codes) does not necessarily mean your CEM is faulty. These are some of the common codes seen in the faulty CEMs we’ve worked on over the years. Thorough diagnostics should always be performed prior to working on a module.
- CEM-1D02, CEM-1D07, CEM-1D08, CEM-1D09 – Control Module Internal Fault
- CEM-DF13 – CAN-H, high speed network. Signal too high
- CEM-DF16 – CAN-L, high speed network. Signal too low
- CEM-6C48 – Transponder type. Faulty signal
- CEM-6C49 – Transponder communication. Faulty signal
- CEM-8F05 – Hazard warning signal switch activated too long
- CEM-8F04 – Turn signal lamp. Faulty signal
- CEM-8F12 – Low beam relay faulty
- CEM-8F22 – High beam relay faulty
- CEM-8F2F – Turn signal relay faulty
- CEM-3F90 – Fuel pump relay short to ground
- CEM-8F52 – Headlamp wash/wipe relay signal missing
- CEM-8F21 – Windshield wiper faulty signal
- CEM-DF17 – Communication with the SWM (Steering Wheel Module) missing
- CEM-9C03 – Antenna / light ring signal missing
- CEM-1A51 – Communication with the SRS Module (Supplemental Restraint System) missing
- CEM-1A52 – Communication with the DDM (Driver Door Module) missing
- CEM-1A53 – Communication with the PDM (Passenger Door Module) missing
- CEM-1A54 – Communication with the PSM (Power Seat Module) missing
- CEM-1A55 – Communication with the CCM (Climate Control Module) missing
- CEM-1A56 – Communication with the DIM (Driver Information Module) missing
- CEM-1A5F – Communication with the ECM (Engine Control Module) missing
- CEM-1A62 – Communication with the TCM (Transmission Control Module) missing
- CEM-1A64 – Communication with the DEM (Differential Electronic Module) missing
- CEM-1A5D – Communication with the REM (Rear Electronic Module) missing
- CEM-1A5E – Communication with the UEM (Upper Electronic Module) missing
- CEM-1A5F – Communication with BCM (Brake Control Module) missing
- And more
Why Replacing the CEM is Difficult
CEM issues are common, but replacing the module isn’t straightforward. The CEM is programmed specifically to each vehicle, meaning that simply swapping in a used unit—even with matching part numbers—won’t work. A new unit requires special scan tool programming, making it costly and inconvenient.
Part Numbers We Service
For your reference, here are some of the part numbers we’ve worked on:
30682981, 30682982, 30728357, 30728539, 30728542, 30759114, 30765148, 30765149, 30765643, 30765646, 30765646, 30786475, 30786476, 30786889, 30786890, 30795115, 31282455, 31282457, 31314468, 31394157
Don’t worry if your part number isn’t listed. We’ll still be able to help!
XeMODeX Solutions for CEM Failures
At XeMODeX, there are three separate services we offer for this part:
- Limited Repair Service (for Power Loss to Fuse 15) – A common failure where the CEM stops supplying power to fuse 15, causing no communication with the BCM. This issue is so common that we have a repair service specifically for it here:
If you’re in the USA, click here: https://xemodex.com/us/product/central-electronic-module-for-volvo-p2-platform-repair-service/
If you’re in Canada, click here: https://xemodex.ca/ca/product/central-electronic-module-for-volvo-p2-platform-repair-service/
If you’re outside the USA and Canada, please contact our customer service team at 1-888-712-2525 or email sales@xemodex.com
For any issue other than the fuse 15 issue, the service required is a Program Transfer service. This involves extracting the programming from your original module and loading it into a good used matching CEM. This allows the replacement module to work in your vehicle with no programming required (in 99.9% of cases).
We have two different program transfer services. The primary difference between them is who supplies the good used matching CEM. Each option has pros and cons, so consider each option to make sure you’re getting the service that’s right for you.
- Program Transfer Service to a XeMODeX supplied unit – We transfer your CEM’s programming to one of our remanufactured CEMs, giving you a warranty on the hardware, and some extra confidence that you’ll be getting good hardware reinstalled into your vehicle.
If you’re in the USA, click here: https://xemodex.com/us/product/central-electronic-module-for-volvo-programtransfer/
If you’re in Canada, click here: https://xemodex.ca/ca/product/central-electronic-module-for-volvo-programtransfer/
If you’re outside the USA and Canada, please contact our customer service team at 1-888-712-2525 or email sales@xemodex.com
- Program Transfer Service to a Customer supplied unit – We transfer your CEM’s programming to a good used matching CEM you supply, which is ideal for mechanics who may already have a good used unit.
If you’re in the USA, click here: https://xemodex.com/us/product/central-electronic-module-for-volvo-program-transfer/
If you’re in Canada, click here: https://xemodex.ca/ca/product/central-electronic-module-for-volvo-program-transfer/
If you’re outside the USA and Canada, please contact our customer service team at 1-888-712-2525 or email sales@xemodex.com
Things to keep in mind
- Occasionally, we encounter a CEM with no keys stored in its memory, resulting in a no-start condition. This issue stems from an internal CEM failure. While reprogramming the keys to the same faulty module may provide a temporary fix, it won’t be a lasting solution. To fully resolve the problem, we perform a CEM program transfer service, addressing the underlying hardware fault before reloading the keys into the module. Due to the additional work required, additional costs will apply.
- The vast majority of CEMs we service are plug-and-play upon return, requiring no additional programming. However, in rare cases, a software reload may be necessary in the vehicle after reinstallation. While this is an exceptionally uncommon occurrence, we believe in full transparency—so while highly unlikely, we cannot guarantee with 100% certainty that a software reload won’t be required.
Why Choose XeMODeX?
- Cost-Effective Alternative to New CEM Replacement
- No Need for Dealership Programming
- Plug-and-Play Solutions
- Industry-Leading R&D and Repair Expertise
If you’re experiencing CEM-related issues in your Volvo, XeMODeX can provide a reliable and effective solution. Contact us today to learn more about our services!
Visit www.xemodex.com to check out our products and services.
