Volvo Electrical Problems – Central Electronic Module (CEM)
A faulty connection or corroded ground typically causes Volvo electrical problems. The Volvo Central Electronic Module (CEM) connections are often the issue. The Central Electronic Module (CEM) is Volvo vehicles’ main electrical module that communicates with the rest of your car’s modules and components. When it fails, it can cause unpredictable intermittent electrical problems.
It is much cheaper to get your Volvo CEM rebuilt service, which you can order on eBay instead of replacing it with the dealer.
2001 through 2013, Volvo vehicles were prone to intermittent electrical problems due to water getting to the Central Electronic Module. Corrosion on the CEM terminals can develop if you:
- live in a humid climate,
- forget the windows open when it rains
- if your vehicle has been in flood.
For example, you may experience an engine turning off on its own or doesn’t start. Random warning lights are coming, such as ABS, an airbag, and a brake warning. The keyless entry is not working.
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Getting the CEM module replaced by the dealer costs $1000+. A cheaper solution would be to repair your existing module. Remove your existing module and send it for repair to a facility that offers Volvo CEM Module Repair on eBay.
Symptoms
A CEM module (or corroded connections at CEM) triggers intermittent electrical problems. The car may work fine when cold but develops random electrical problems when hot, cold, or humid. Here are some problems you may notice.
- The security system is not working.
- Brake, please make a safe stop error on the dashboard.
- Ignition issues can’t start the car.
- Waring Lights Come On / Indicators Failure.
- Wipers turn on randomly.
- The steering wheel is hard to turn.
- Instrument cluster lights turn on.
- Gauges don’t work.
- Radio works intermittently
- Accessories stop working
- Lights don’t work intermittently.
- Wipers do not work or come on sporadic.
- CAN comms fault on the diagnostic tool
- The ABS light comes on randomly
- No communication with the CEM unit
- Brake failure
- Limp mode
- Not start
- Immo fault
- Engine Cutting Out Randomly
These are some of the most common issues. Remember that depending on how and where your CEM has failed, you may only experience one or two symptoms. Several problems may be due to a defective body control module or Light Control Module (LCM).
How to Diagnose Volvo CEM Module
To troubleshoot Volvo’s electrical problem, you can start by reading the fault codes from the CEM module. You will need a Volvo scanner, as generic OBD2 scanners can’t read CEM fault codes. The YOUCANIC Scanner can read all the control modules of a Volvo vehicle, including CEM fault codes.
If you cannot establish communication with the CEM module, the terminals at the module may be corroded. You can remove the module and inspect it. If you cannot repair it, send it to a third-party service that fixes the Volvo CEM module.
How to Remove and Clean Volvo CEM
Here are the instructions for removing and cleaning the Volvo CEM module.
- Disconnect the battery. If your battery is in the engine bay, open the hood by pulling the hood release under the dashboard. Use a 10mm socket to disconnect the negative battery terminal. If you don’t have a battery in the engine bay, the battery will be in the trunk below the floor carpet. Open the trunk. Lift the carpet. Remove the metal plate on top of the battery, then disconnect the negative battery terminal.
- Locate the CEM module under the dashboard on the passenger side for 2003 to 2013 models. From 1999 – 2004 XC90, XC70, V70, S60, and S80 CEM are under the driver’s side dashboard.
- Remove the kick panel or fabric cover under the dash. You will need to remove the plastic retainers to pull down the cover.
- Now, the CEM module is exposed. Twist two screws on the CEM and pull down the module.
- Disconnect the electrical connectors from the CEM. To remove the connectors, pull back the lever to unlock it, then lift it out.
- Disconnect the electrical connections from the bottom of the CEM module as well.
- Inspect the connectors and pins on CEM for corrosion.
- Remove the black relays from the CEM and inspect them as well.
- Use a small brush to clean the contacts with the contact cleaner.
- Once you have cleaned all the contacts, allow the CEM to dry completely.
- Apply a light coat of electronic contact protector (dielectric grease) on each terminal to improve conductivity.
- Reconnect all connectors to the CEM. Each connector’s unique shape will only go into its own port.
- Secure the CEM on the two brackets that are under the dashboard.
- Tighten the two screws
- Install the cover under the dashboard.
- Reconnect the battery negative terminal.
- Start the car and verify everything is working properly.
Conclusion
Volvo vehicles are known for their reliability and durability, but like all vehicles, they are prone to electrical problems. Intermittent electrical issues can be frustrating and difficult to diagnose because they don’t always happen consistently. Some of the most common symptoms of intermittent electrical problems in Volvos include flickering lights, failure of electronic components, and loss of power to certain systems.
The Central Electronic Module (CEM) is a critical component in a Volvo vehicle that controls many of its electronic systems, including lighting, instrumentation, and communication with other modules. When the CEM fails, it can cause a variety of intermittent electrical problems, including those mentioned above. If you are experiencing intermittent electrical problems in your Volvo, it’s important to have the CEM checked by a professional to determine if it is the source of the issue. In many cases, replacing the CEM is the solution to resolving the problem and restoring the normal functioning of the vehicle’s electrical system. The YOUCANIC full system scanner is capable of reading fault codes from the CEM module. If you get no communication error when trying to access the CEM module, this is an indication that the CEM module is defective.
Frequently Asked Questions
My car won’t start after cleaning the CEM
Check that the connectors to the CEM are fully inserted and locked properly. Check the battery negative terminal is tightened.
Which Volvo models have this problem?
Primary Volvos on the P1 platform. Volvos from 2004 to 2013 have a CEM module under the dashboard on the passenger side.
Which cars are Volvo cars based on the P1 platform?
2004-2012 Volvo S40 II (P11)
2004-2012 Volvo V50 (P12)
2006-2013 Volvo C70 II (P15)
2007-2013 Volvo C30 (P14
Does this problem affect other cars?
Yes. This problem can affect other cars based on the P1 platform. Examples include Ford C1 models such as Focus, Kuga, Escort, Escape, Transit, Linkon MKC, Mazda Alexa, Mazda3, and Biante. Sabb vehicles as well.
We hope you find the Intermittent Volvo Electrical Problems guide helpful. Check these troubleshooting and repair guides for more help on your Volvo.
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