99 S80 Rough idle at start

daytrader1981 · Post by **daytrader1981** » 26 Apr 2011, 21:14

I recently bought my 99 s80 2.9 and am in the process of fixing it up. The car has a very rough idle at start where is struggles to stay running and then about a minute or two later, the RPM's level out and the car starts to idle properly. The CEL is on, and the codes that have registered are P0103, P0113, and P0118. I have replaced the Mass Air Flow sensor already and that did not fix the idle, nor eliminate the P0118 code. I have a temp sensor on order.

Any suggestions on what to look at and fix? I am new to Volvo's so I am on a steep learning curve. Could it be an issue with the ECM? Need new plugs? I have also read something about a TPM S/W update, but not sure if it is applicable to my model.

Thanks for your help!

Post by **precopster** » 27 Apr 2011, 03:16

The ETMs usually fail by giving you an idle which goes high then low and alternates b/w these two states.

From what I've seen a rough idle that changes to a smooth idle after warm up is not consistent with ETM failure.

Sounds more like a coil or coils that arc for afew minutes to the spark plug well due to moisture, then when the engine warms it stops arcing. This arcing can throw other CELs that are not related. My 960 did this for 12 months until all coil packs were replaced.

Try this link to help with code identification:

https://www.matthewsvolvosite.com/volvo- ... ble-codes/

daytrader1981 · Post by **daytrader1981** » 14 May 2011, 09:19

Thanks for the response precopster. I pulled the coils off and checked the plugs and cleaned the residue, but it still didn't fix the issue. The car still has a rough time idling at first, and I have noticed that it hesitates some times while driving. I am starting to think that I have two issues, 1 electrical, 1 fuel system related or that the ECM is bad.

Things I have done so far, or know that were done by the previous owner.

So far I have:
Replaced Mass AirFlow sensor - replaced to fix the P0103 code.
Result: No fix, still has the code.

Replaced the Engine Coolant Temp Sensor - replaced to fix the P0118 code.
Result: No fix, still has the code, and the temperature gauge still doesn't work.

Known previous work:
Fuel pump replaced, fuel lines replaced, Exhaust gaskets replaced, starter replaced.

I have also noticed that the air conditioner doesn't work. I used the wiring diagrams provided on this website (although thier is 2 for the 99 S80, so not sure which one to use) to troubleshoot the system, and ended up jumping 12V to the compressor to see if it would turn on and it did, and actually cooled down very well, so I am thinking that the ECM could be the issue, or a grounding problem, with not only the A/C but the other CEL codes that will not go away.

Has anyone had these issues or know how to troubleshoot the ECM? Any and all help would be much appreciated.

Thanks!

daytrader1981 · Post by **daytrader1981** » 15 May 2011, 19:04

So I took the ETM off and cleaned it up and while it did help with the rough idling and did see improvement in performance, the RPM's still bounce around a lot when starting, even to the point to where it dies. I am suspecting the ETM module is the problem for at least some of the problems. Does anyone know if the software update to the ETM's fix anything? I called a Volvo dealer and gave them the VIN of the car to check the history and they said that it hadn't ever had the update. Since the car is out of the warranty period I don't want to spend the $200 for a SW update if it doesn't do any good.