My 2001 V70 T5 has had a problem for the last year or so. Try to start the car and it will start momentarily, the DSTC Service Required message comes up and the engine dies. Will not start immediately after. Let the car sit for a few hours and it starts right up...no DSTC message. Sometimes as I'm driving the DSTC Service Required message will come up and the car goes into limp mode. Last time it happened right when I hit a pretty good bump in the road. No low gear, no dash gauges, but it will get me home.

I've had it at the dealer twice for 2-3 weeks at a time. They couldn't get it to repeat and insisted there were no codes. Took it to an independent European car repair shop. They said there were some fault codes indicating lack of communication between the ECM and CEM? Offered to reload the software...might work. Next would be to check connections and replace wiring harnesses....might work. Next would be replacing the computers....very expensive.

Is anyone else experiencing this problem and have you found a solution? I'd like to keep the car, but I can't rely on it the way it stands now.

 

I still struggling with this problem. 2001 V70 T5 will periodically get a DSTC Service Required message and will crank but not start. I've had it at the dealer a couple times and they've not been able to duplicate the problem and claimed they saw no codes.

I got a Volvo code reader and am getting the following stored codes: CEM-1A5D, CEM-1A62, CEM-1C01. Looks like I've got a problem with the Central Electronic Module, but I don't know how to determine if it's a problem in the module itself or a related electrical/contact problem.

Any ideas?

 

did you check and clean/reset the connectors to the CEM? Also, sometimes the wheel speed sensors can set off the DSTC codes (I didn't look at your specific codes to see if this may be in play).

 

Pulling, cleaning/resetting the CEM connectors is probably going to be my next step. Thanks.

 

On some advice from Xemodex I ran a heat stress test on the CEM. But before I did I read the codes on the car again. A bunch more codes:

BCM-0093
CCM-007
CEM-1A5D
CEM-1A62
CEM-1C01
ECM-510F
ECM-928C
ECM-530B
ECM-720A
ECM-E003
ECM-902A
ECM-959F
ECM-903F

Obviously, a lot more codes than I read before, but still no “DSTC Service Required” message and the car started just fine. I did notice that after I had the ignition turned on to accessory for about 2-3 minutes I got a low voltage message in the information window. Could this possibly all be a bad battery problem?

After reading the codes above I erased the codes from the system, started the car and heated the CEM with my heat gun for 5 minutes. No negative response. No messages. No codes after the heat test. Car ran fine.

 

Did you put a volt meter on the car? If the alternator (or voltage regulator) stops charging as the regulator diodes or a weak connection heat up, your system voltage may drop below the volts required by the various computers - which can then throw a happy meal of codes.

 

I have not put a volt meter on the car yet. I've got a volt meter, but I don't know where on the car I'd measure the voltage. Is it pretty straightforward?

 

you should be able to use the lighter socket - you want to monitor the entire system's voltage to see if the alternator / voltage regulator is cutting out. I bet Autozone carries something like this: https://www.ebay.com/i/323110792359?chn=ps