Hey guys.

My wife has a 2009 S40 2.4L that has been going through batteries. After like the third battery in a year we took the car into a volvo specific shop and paid them to do a starting and charging system diagnostic, with the hopes it was just a bad alternator that I could then replace myself.

They came back with a $1300+ quote saying the CEM is bad. He said he needs to replace the CEM ($648.60 part) and load new software on it ($120.95 for the software.)

This whole deal with paying for software seems sketchy for me. Seems to me that if you put a new control module in your car it should have the software loaded on it, doesn't it? The guy was also ADAMANT that this was not something I could do myself, saying that you needed special computers to do the repair. I worked in an auto shop earlier in life and still have my tools but I don't have any computers to interface with newer cars.

Am I over reacting and should I just pay for it? Is it worth shelling out another $100 diag fee to another shop for a second opinion?

 

For good reasons,* a dealer's response will often be "Replace the unit." In my case, I was told "Replace the DIM (instrument cluster)." It turned out to be a single vaporized LED. I fould that out by scanning my car with VIDA.

A basic starting point for any Volvo owner that is doing more than leaving the car with the dealer on repairs is a Chinese clone DiCE / VIDA unit. VIDA is the dealer's analytic software. Combined with the DiCE interface, it will let you examine your car's operation at leisure. Coincidentally, it costs about what a single "Diagnostic scan" at a dealer does.

My suspicion is that Volvo is keeping a database of EVERY VIN number. "Software downloads" then will ensure that the specific code YOUR car is running conforms to the equipment and software dates of all your car's fifteen CPU's.

That said, there are services that will sell CEM's pre-programmed for your car at much lower costs.

Also, I have seen folks reporting success in "restoring" CEM operation by re-flowing the solder on the various modules.

*By replacing the entire module, the dealer is assured of FAR fewer callbacks, along with a more efficient shop workflow. If it costs YOU an extra grand, what's the harm?

 

Thanks for the reply. The dealer had a printout of all the trouble codes that the CEM was throwing. He didn't give it to me with the quote but I remember there were quite a few codes. I'll have to see if I can get that from him.

I like the idea of taking the CEM out and repairing it. Seems the lowest cost thing to try and we're not in a big hurry since we have another vehicle for her to drive while the Volvo is down.

 

Aside from the conspiracy theories of why dealers replace CEMs, the problem here is the CEM and ECU are "mated" due to the immobilization system (aka your no start security feature to prevent hot wiring etc). The CEM itself is a collection of relays and similar electronic bits that are soldered onto a circuit board so the usual problem is one of those solder joints cracked or a relay etc is toast. There are services that will replace and resolder any bad components to your original. However if you need to replace the whole unit (whether with a new one or from a used replacement) the CEM and ECU need to have their software reloaded to mate them. You can either have a volvo shop install your replacement CEM and do the software load (seems the going rate is $150-200) or you can ship your CEM and ECU to a shop that will repair the CEM and reload the software into the ECU. go to xemodex.com for their mating service and more info on the process. You can google around for similar repair services. To shop for a used CEM, check out Car-part.com