Vida CEM swapping

[cn90]

Hi guys,

I understand PEM issue is somewhat more common than CEM failure.

I have a few questions re CEM failure:

1. At what mileage does it happen to you guys?

2. How do you distinguish a PEM failure vs CEM failure?
In otherwords, how do you diagnose CEM failure?

3. For every 10 PEM failures, how many CEM failures?

4. Is the best option still taking your CEM out and ship it for repair?

5. Besides Xemodex in Toronto area, is "yagger" in San Jose CA the other option?
How much is it to fix a CEM (i.e. bad component repair)?

[cn90]

Another CEM question: wondering if a DIYer can buy the relays (or whatever they replace during a rebuild).
Many people here know how to solder etc.
Is this even possible for a DIYer?

[yagger]

5. Besides Xemodex in Toronto area, is "yagger" in San Jose CA the other option?
How much is it to fix a CEM (i.e. bad component repair)?

Be sure ))
Yes, we can fix, we can transfer data to replacement module, we can synchronize modules if need, we can program keys and remotes, we can renew keys and remotes, we can do a looooot stuf.
Sorry about our poor site, reason why, because we are not businessmen, we are engineers. But we will try to put there info about our experience and possibilities.

[RickHaleParker]

Short answer is: "No".

This is what was throwing me off.

Because Renesas speaks through serial port in boot-mode, all you need is a FTDI adapter/chip to translate between serial and USB

The serial pins on the chip are TTL logic, not RS-232 logic or USB logic. That you need is a USB to TTL converter not a USB to RS232 converter. RS232 is what old timers think of as serial.

[vtl]

PEM? A fuel pump controller? They fail more regularly than CEM because Volvo in its eternal wisdom put it under the chassis, open to all road moisture, salt and grime. There's TSB to relocate PEM into trunk. Good news is it is easily replaceable, no software reload required.

Two big CEM relays are Tyco V23134-J52-X455. Tyco is no more (acquired by TE). You can't easily buy this relay, only Chinese knock-offs that you should avoid. I think this is the replacement: https://www.onlinecomponents.com/te-con ... 31463.html I've got 4 of them just in case, but sourced a used relay from the donor CEM for my repair.

DIY is easy. You need a multimeter and hot air gun. Find the bad relay. Good relay has resistance of 74 Ohm (90 Ohm coil + 470 Ohm resistor in parallel):



Bad is 470 Ohm (broken coil):



Heat it up with your hot air gun, it will fall down. Clean the pads, insert new relay, use hot air gun and some soldering+flux to solder it back.

P.S.: Volvo thinks this a major problem worth of $1600 in customer's bill.

[vtl]

The serial pins on the chip are TTL logic, not RS-232 logic or USB logic. That you need is a USB to TTL converter not a USB to RS232 converter. RS232 is what old timers think of as serial.

I had my CEM reloaded via old PL2302 USB-to-RS232 adapter that I've got for like $1 ages ago It has got a real DB-9.

USB as is you can't use, because it is using a differential signalling and a complex protocol, to start with.

OBD CEM pin cracker is on the way, thanks to international cooperation

[RickHaleParker]

OBD CEM pin cracker is on the way, thanks to international cooperation

PIN Cracker! ... You got the algorithm to calculate the PIN from the BIN file?

[vtl]

PIN Cracker! ... You got the algorithm to calculate the PIN from the BIN file?

The software to get PIN from BIN was mentioned on previous page. What I'm trying to do now is PIN-over-OBD.

[vtl]

So the PIN is located at address 0xFFE000. Flash starts at address 0xFB0000, so when you get the dump the PIN is at offset 0x4E000 in the file. The PIN byte sequence in dump is not linear.

For example, this is PIN from my dump:

offset __ B3 B1 B5 B0 | B2 B4 XX XX |
0004E000| 53 38 03 21 │ 18 02 FF FF │

PIN = B0 B1 B2 B3 B4 B5
PIN is 21 38 18 53 02 03

This way you don't have to rely on the windows software to dig out the PIN.

[cn90]

I don't understand this Xemodex thingy...

If one can find the Tyco relays etc. etc. (I see the Tyco relays on ebay FYI), why can't one replace the failed component(s) him- herself and done.
No need to re-program etc. etc.
If Xemodex can turn it around in one day, it must be a simple job for those with soldering skills.
Many people here can solder...