I recently replaced the battery in my 2007 s40. After driving it for 100 miles, I took it to get it smogged. The technician could not pull up anything. When I tried to connect my OBDII, I got a linking error and the check engine light came on. The technician then pulled a U0001 code. From what little I understand, this is a CAN BUS issue and means that one or more sensors is not communicating with the onboard computer. I checked all of the fuses, and I'm hoping that there is some diy help out there. Any thoughts? Would cleaning the CEM do anything?

 

Did anything "interesting" happen during the battery replacement (maybe reverse polarity for a second)? Big spark on reconnection of the battery or when plugging in the OBD reader?

 

No. Nothing. BTW I never had a check engine light for this car so I don't think I've ever tried to attach the reader before. And the car runs fine.

 

There's probably something (a module of some sort) on that shared buss circuit that's fried. You're just going to have to ID all the modules that use the CAN Bus and disconnect them one at a time until you can use your OBD reader.

Good luck with that - Volvo "service manuals" are hit and miss, IMHO...

 

I was afraid you were going to say that. I’m guessing there is nothing that is going to show me the location of those modules.

 

Vida does - the Volvo factory service manual. A free working stolen/hacked version is easily found on the internet. Swedespeed has a copy in their technical/obd section. There's a learning curve but if the wiring diagram disk is included - everything is there to diagnose your car. You could talk to every control unit directly in the car if you purchase a DICE unit. (~$100)

 

I appreciate that I'm out of my element here, but that is often the case. I'd like to avoid a large bill if possible. I read the following, and it seems like it might apply to my situation,

"Various kinds of problems can occur on other CAN-equipped vehicles when the battery is disconnected or goes dead. The modules in the CAN system require a certain amount of voltage for their Keep Alive Memory settings. If this is lost, the module will forget these settings and may not function properly until it has time to relearn the lost data. In some cases, this requires a special relearn procedure using a scan tool because the module can't do the relearn by itself. And on some vehicles, the module may go to sleep and not wake up until it is pinged by a scan tool or the main gateway module (usually the body control module). Relearning procedures typically require a factory scan tool or a professional level aftermarket scan tool."

Is the Dice such a tool.

 

Volvos don't require a ping from a scan tool to activate things. Sometimes you have to read and erase codes to get things to work - but that's usually something like a headlamp bulb shorted and blew a "circuit breaker" in the central electric module. - Which stored a code and won't let current go to that new headlamp bulb you just put in until you read and erase the code.

I have not seen control units have problems by simply replacing the battery. Replacing the battery may erase the drive cycle information and require that to be completed to pass emissions. A drive cycle occurs during normal driving and tests all emission related components in a specified order. The inspection station simply plugs in to verify the car has completed and passed it's own emission inspection. There are ways to complete the cycle quicker by following a certain schedule, but that is usually only needed after an emission repair and the customer needs an e test to get their tag NOW.

Some cars will never complete a drive cycle if they are only driven short distances for short periods of time.

And to answer your question - a DICE interface combined with the free stolen/hacked version of VIDA 2014d (and usually a win 7 pro cpu of yours) can do any possible communications with all control units in your Volvo - read /diagnose/erase/activate functions and set certain parameters.

 

The battery was dead for a while (Covid Car). I got a jump but after running the car for an hour the battery didn't hold the charge, so I replaced it. I put 120 miles on the car and the smog tech still couldn't get a reading. I saw VOLVO DIAGNOSTIC SCANNER TOOL S40 S60 S80 S90 V40 V70 XC70 XC90 C70 C3 Vida Dice on ebay for $113. I'm willing to take a shot but would rather not throw good money after bad if I'm likely to have the same linking error that I'm getting on my OBDII scanner. Thanks for responding.

 

If this is your first attempt at diagnostics I would not recommend going the VIDA/DICE route. Unless you are computer savvy, patient, have plenty of time and have an extra win7pro cpu you can use. (there are other choices, a $100 usb bootable stick with vida preinstalled is one) . There will be no help desk for your stolen/hacked software and training is seat of the pants. Click and pray then try again - If the software does not install correctly you have to start with a clean hard drive sometimes. For reference my personal clone dice was about $85 a few years ago, and the first one did not work.

Here's a couple of random screen shots - if you have a Canbus problem - those can be especially hard. You really have to understand electronics.

The last screen shot is from my car showing the network and codes stored - tire pressure monitoring problems on a 2015 - I've fixed Volvos for 40 years but I can't fix that - I don't have a $2500 tmps special tool - my trusted local tire shop with a tool could only suggest swapping parts. So I will need to go to a dealer to figure it out. The solution will either be software for the CEM, a bad receiver (for the tpms signals) except there are no receiver codes, a new CEM or less likely 4 bad wheel sensors,

 

Looks like I'm cooked. What a drag. There are zero issue with the car (other than some door lock issues) other than getting it smoged.

 

You might look for an ad in your local Craigslist - I've seen folks who offer flat-rate diagnostics for cars like Volvos, using the appropriate software. Naturally, the person might not be a real subject matter expert, but it might help, and won't cost anything close to what driving by a dealership will...