Help diagnose: 2000 C70

elav · Post by **elav** » 20 Oct 2011, 15:02

Car: 2000 C70 HT Coupe with manual transmission
Issue: Every once in a while it feels like the engine misses. This usually occurs when the car is under load and I'm trying to accelerate (e.g. on the highway and press on the throttle a lot to accelerate, or sometimes when I'm starting from a stop).
Other symptoms: I had my ETM "cleaned" by Volvo 2 years ago and the MAF sensor replaced at that time. Every once in a while my ETM light will come on but eventually goes off during the drive or the next time I start the car, etc. The issue I have can be reproduced whether the ETM light is on or off. There are no codes to read by the OBD-II reader.

I would really like to diagnose this issue before I throw money at it. At one point I was thinking it was the turbo control valve. It could also be the ETM as the ETM light goes on every once in a while but it could also be something like a fuel issue (clogged injectors, etc.). I'm looking for an approach to diagnose before I start randomly replacing items. Any help is appreciated.

Post by **Juan62** » 20 Oct 2011, 16:39

Check/inspect all vacuum lines/hoses to include your Turbo Tube (Fresh Air Intake), PCV (Flam Trap), CBV (Compressor ByPass Valve), and Turbo Control Valve(TCV). If your MAF and ETM is working properly, that is where I would start. If you do decide on a new TCV, go with an HD TCV by IPDusa.com

Post by **BEJinFbk** » 20 Oct 2011, 19:58

You know that your ETM is a poor design and IS gonna die, right?
Plenty of good info here: https://www.matthewsvolvosite.com/forums ... m.php?f=12

FCPEURO · Post by **FCPEURO** » 20 Oct 2011, 20:36

+1

If that unit is original, it is only a matter of time. Volvo extended the warranty for 10 years on it, but unfortunately, it is no longer covered.