v70 2004 - CEM from same model, but different CEM number, will it still work?

Hello everyone,

I ordered a CEM from a donor car that was manufactured only two months after mine, thinking I could just transfer the chip from my CEM to this one. However, when it arrived it have completely different numbers and look completely different.

My question now is:

Would it work in my car anyway, as long as the configurations are transferred from my CEM?

Would a CEM from another model, but still same numbers on CEM, work in my car, as long as I transfer the configurations from my CEM, or maybe even just the chip?

My CEM have numbers 8688513 8696035 and the new CEM have numbers 8696098 8696040. I have found my CEM numbers on CEMs for models like s40, s60 etc.

Thanks in advance,

Ami

I do not know.

i have read many parts posts over the years and the consistent answer is that modules are addressed to the car and need to be match or things won't work.

By "configurations" do you mean the plugs? Have you opened these CEM's? Is a chip swap even possible?

Next time go to a junkyard with your car and try them. They still might say, "No tryouts on electrical parts". Then it'd be up to you to remind them that they don't sell any of these things anyway and that a trial is the only way you can tell.

They say Volvo will only program sub-assemblies if you buy them new from Volvo. Got any friends in the dealership?

How did your original CEM fail?

Georgeandkira said:

I do not know.

i have read many parts posts over the years and the consistent answer is that modules are addressed to the car and need to be match or things won't work.

By "configurations" do you mean the plugs? Have you opened these CEM's? Is a chip swap even possible?

Next time go to a junkyard with your car and try them. They still might say, "No tryouts on electrical parts". Then it'd be up to you to remind them that they don't sell any of these things anyway and that a trial is the only way you can tell.

They say Volvo will only program sub-assemblies if you buy them new from Volvo. Got any friends in the dealership?

How did your original CEM fail?

Click to expand...

The main issue with my car is that it's not starting at all. Gone through many troubleshooting steps I have come to the conclusion that the CEM is involved.

I have been in contact with guys programming CEMs and they say that as long as it's the same year and model, it should work, but I haven't seen anyone ever getting two different CEMs before when ordering one from the same year and model.

I have 3 CEMs now, my original, one from my own donor car, a v70 2001, and this new one from another v70 2004.

The CEMs that I already own looks almost identical, definitely have the same chips, but obviously different programmings (configurations) as I've tested my 2001 in my 2004 car already and it behaved really weird from the moment I connected the battery.

I have been promised that its possible to get the 2001 to work in my 2004 by transferring the programming (configurations) from the chip, or transfer the chip itself. But it will not work vice versa.

I removed the original CEM as part of a troubleshooting step, and, against better judgement, decided to, out of curiosity, disassemble my original CEM from the frame. Unfortunately while doing that I accidentally removed some components from the card. I could probably solder new ones there, but without a picture of an identical card I cant be sure I have found all the missing components to get it to work. Plus, I'm not even sure it was without fault to begin with.

During my troubleshooting I missed one important step and that was checking the logs during the start-up cycle between the ECM and the CEM as I suspect that the CEM have lost the identification number of the ECM so they can not communicate anymore and therefor the car can not start. The second cause I suspect is faulty CEM as its very common on v70 2004.

At the moment I'm looking at either transferring the chip from my original CEM to my 2001 and continue the troubleshooting and from there either go to volvo to have both CEM and ECM configured again (if its lost the identification) or buy one of the programs to do it myself.

Or if the CEM is faulty it might be solved by simply transferring the chip from my original to my 2001 one.

However, I would very much like to get a more recent CEM and just transfer the configuration either by getting a guy online to do it, transfer the chip itself or to buy the program myself and do it.

The questions above are mainly out of curiosity, but would also help me in deciding my next step, for example if I want to buy a 4th CEM that are identical to my v70 2004, or if I can get it to work with this new v70 2004, despite looking different.

lefedor said:

Hello, you can try start car with original CEM but apply PC Fan cooling, it may work, cause most reason - flash memory fail while warmup, next inspect memory chip and CPU for dissoldered legs.
If it's not strait help, CEM should be inspected precisely.

I strongly recommend not mix memory chip IC's because they fail for the aging reasons and heating while removal-installation can do final damage to it, so You should be very gentle with them.
The way I solve this issue and way I can recommend - extract data while IC still on board, several times, check control sum of each readout, buy new memory IC, write data to it, THEN replace memory chip, install heatsink on CPU/flash, install good silent FAN using voltage regulator downstepping voltage to 8..9 volts so FAN is noiseless.

Click to expand...

Can you recommend a program to read and write this data with, that would work with these models?

flash readout

Amiliana said:

Can you recommend a program to read and write this data with, that would work with these models?

Click to expand...

Best option is dealer/engeneer level software, its dongle locked so it depends if you can give/send it to equipped engineer. This allows read flash over OBD data lines.

Second best option is BDM readout through CPU , smth like BDM100 can handle it, requires soldering skills, commonly available in ECU repair services, aliexpress.

Third option is carefully unsolder flash on read with regular programmer with sop44/psop44 adapter ( TL866 can do it ) - remove/unsolder heat sink (someones cuts it but it can damage PCB) while keeping cpu/flash shielded from direct heat (few layers of metal foil), weak soldering joints with new solder, desolder flash.

Than it's possible for data to be transferred to brand new flash IC, soldered back and etc..(heatsink/shield install, PCB water-resistant coating apply, Fan option).

I just had an interesting development with my 2004 XC70. I bought it totally unknown with a dead engine --previous guy had bought unknown at auction. Suspiciously, there was a box of volvo relays in the back, along with other components.

I put in a replacement engine, and a new valve body in the transmission, and the car worked like a charm, but battery would randomly go dead - generally after a day or more of sitting, depending on how much it had been driven prior, presumably due to how much the battery had charged.

Knowing this would be a challenge to troubleshoot, I installed a 300amp shunt and digital ammeter that I bought on Ebay (a gamble) and it worked like a dream. Measures down to 1 mA of current, and I can leave it connected all the time, and when the car sits, I just look through the window and can see the current.

Sometimes it reads 000mA, and cycles to 025mA with the same cadence as the alarm LED light - presumable that is the load.
However, it sometimes draws a steady 075mA continuous --enough to draw down a partially charged battery in a couple of days.
Other times, it would draw a couple hundred.

Glove box light is not the problem
I jumpered the rear hatch so that I could leave it open and the car registers it as closed
I also "locked" the driver door in the open position so that the car would simulate being locked and at rest

I pulled every fuse and every relay (Execept on the CEM - I am a little lazy)

Nothing makes any difference, except the fuse to the CEM. This drops the current to 000mA instantly, and it stays there.

Now the interesting part. With the CEM power supply fuse out, I started the car and ran it for a while, while messing with switched to see what worked and what did not.

When I turned the car off, and put the fuse back in, the SRS Urgent message displayed. I turned the car on and off a couple times, and then cleared the code with my scanner.

Since that time, there has been no parsitic drain on the battery.

Is this luck, or did I somehow cause some sort of a reset in the CEM?