2000 S80 with communication/starting issues

marrad · Post by **marrad** » 07 Aug 2012, 18:08

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

marrad · Post by **marrad** » 10 Aug 2012, 20:39

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?

marrad · Post by **marrad** » 01 Jan 2013, 08:34

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?

tray · Post by **tray** » 02 Nov 2016, 07:14

I have a 2006 S80 that suddenly would not start --the car would start and then shut down. Towed to mechanic and as soon as it came off the tow truck, it started fine--continued to be fine. Mechanic could not find anything wrong because it was working fine. About one month later, same thing--same result--towed to shop--then started up fine. Any suggestions??

Post by **yagger** » 02 Nov 2016, 16:46

Chip in key. Try to use another key if you have it.
When you try to start, you need to listen sounds like working relay also.