2000 S80 with communication/starting issues
 

A couple months back our 2000 S80 started having periodic starting problems - cranking and cranking but not turning over. I had the car scanned and all the codes were communication errors - missing signals to ECM, CEM, etc. plus other issues that were not starting related. Eventually we could not start the car at all and all the attempts I guess did in the battery because it died. If it was weak all along you wouldn't have know it by how the starter was cranking. Anyway, I replaced the battery today and the car started immediately. Ran great. Shut it off and back to cranking and cranking but not starting. Disconnected the battery for 15 minutes, tried again and started right up. Any ideas on what to check or what the cause may be? Thanks in advance!

Mark

One of the codes that pulls which is directly related to starting is CEM 1A62. I've read the suggested things to check regarding this code but have a question. Does the fact that the car always seems to start if the battery is disconnected rule out any possible causes or strongly lean toward a particular cause below?

No power to ecm
open circuit in the ground lead to ecm
contact resistance in the terminals
open circuit in the wiring for the CAN high speed network to ecm

If the antenna that picks up the key goes bad, can it cause communication issues like this or would it be completely different symptoms?

Here is what has already been done. I have already replaced the ECM, CEM and ABS modules and the problem persists. The scenario goes like this. The car will start once and everything works fine (except an srs error due to the driver seat airbag). When the car is turned off it will never start again unless the battery is disconnected or the ecm removed and reset. Then it starts right back up again, but only once.

The problem is the car looses communication within the network. There are three codes that keep coming back (others have come and gone) – CEM-1A62 (signal to ECM missing) ABS-0093 (Control module communication error) and SRS-0034 (the driver seat airbag issue I mentioned).

I replaced the ECM first, but that didn’t solve the communication problem. The CEM seemed like the next most likely culprit so that came next. A dealer looked at it afterward and said the ABS module seemed to be bringing down the network somehow so I replaced it with a BBA remanufactured unit last week. But I still get the communication errors with the ECM and ABS once the car has been run and turned off.

I noticed when the car was scanned the ABS light on the dash started blinking and sometimes an STC service required message appears. But once you start the car all the messages (except the srs error) go away and the car drives fine and there are no abs or stc problems and the cruise control works fine. I figured since I had never heard of someone saying their abs module was taking down their can network the chances that I have two modules in a row doing so are slim. But the abs issues (blinking light and stc message when the key was in position II before starting) do seem to confirm what the dealer thought, that communication seems to be interrupted somewhere around the abs system.

Does any of this information lead toward any specific cables or connections to be checked or any other suggestions?

I think your problem is software related since u mention that u replace the ecm. If u change the computer of the car with another one is not gonna work unless you buy one from the dealer and the programmmed it specifically to your car. There are a couple of places online that fixes the ecm. Again i really think you problem is software related so i will say u need to take the car to a dealer so they can diagnosed and go from there.

The problems started with the original parts in the car after I owned it for a year or so. It was first just an occasional hard starting issue and the STC message did appear a couple of times.

Eventually the car wouldn't start at all and over a few weeks of trying I drained the battery. When I put in a replacement it started right up. That seemed strange as the car had been cranking fine. So I turned it off and it wouldn't restart. Disconnected the battery for 5-10 minutes and started fine again.

Eventually the car was scanned and the module screen showed it was loosing communication with the ECM after it started. That's when I discovered pulling the ECM would restart the car as well. The car was at a Volvo dealer last week and they said communication seemed to be getting interupted at the ABS module but I decided to put in a remaned unit myself as the car is no longer worth to me the $900+ they wanted for a new one. That did not fix the problem and since an ABS unit bringing down the CAN network is so rare or unheard of I felt having two units in a row doing so is very unlikely.

The ECM and CEM both came from Xemodex. I sent my original parts and they reloaded the software. The car still runs great but nothing changed with fixing the starting issue.

Is it possible that software in an original part get corrupted somehow and a rebuilder wouldn't be able to recognized it so reloading it on another part would get the same result?

I did eventually get this fixed and some have emailed me about similar problems. I took the car to a dealer and they said the problem was within the high speed can bus and recommended I change the ABS module. That didn't fix it either. So after replacing the ecm (reloaded the software from original to another ecm with the same part #), cem and abs modules we did a forced reload of the ecm software and the problem ended.

Forced ECM reload
 

I have the same problem. I was told to change the engine and I did, sent the ECM to be fixed (No software unpdates done, they said that some modules in the ECM were bad and were replaced) sill not fixed. (my 2003 Volvo s80 is at the point where it does not start at all). Now I am told the problem is the CEM. I am tired of throwing money at it. You are the second person to say that a forced reload of the ECM software fixed the problem. Can I ask how and where you got the forced reload of the software done? Was it at the dealer? They want WAAAY too much money! (I know this thread is old but I am at my wits end now!)