C70 Limp Home, no codes or lights

glucas82 · Post by **glucas82** » 20 Mar 2013, 16:10

Sorry if this info is on here somewhere, I'm new to the forum and looked around a bit but couldn't find it.

I have a 2000 c70, purchased about a year ago. About 2 months ago, before I knew anything about ETMs and MAFs and Service Campaign 155, I started dropping randomly into what I now know is Limp Home mode. No warning lights of any kind. I took it to a shop; they diagnosed it as low trans fluid, topped me off, found a bunch of other problems that they fixed, and sent me on my way. Not 5 minutes from the shop, boom. Limp home mode. I brought it back, they suggested MAF. I drove it, when it limped, I pulled over and unplugged the MAF. The car died. If I've done my research correctly, this means the MAF sensor is fine, yes?

So I moved on to the ETM. I do still have the original, white-label ETM. I have scanned the computer with the OBD-II and got no DTCs. I have documentation saying the Service Campaign 155 software upgrade was done. But it still limps.

Anyone have ideas? Is it the ETM? I obviously don't want to drop the money on that if it's something else. Any advice or help is appreciated; I've been to a few shops and no one seems to be able to help!

Post by **mikealder** » 21 Mar 2013, 01:50

Start by taking the ETM off the inlet manifold and clean it out, carbon builds up on the inside of the inlet tract, this can cause the butterfly valve to stick which in bad cases can trigger the car to limp mode, I usually spray the inlet tract of the ETM with carb cleaner, make sure the area where the butterfly valvesits at idle (i.e. shut) is free from any carbon/ dirt - Mike

Post by **precopster** » 21 Mar 2013, 04:38

If the accelerator pedal is moved to a partially open or open position and the throttle butterfly doesn't follow there will be throttle codes because of 2 scenarios:

1) If an impediment to the operation of the butterfly occurs there will be an over current code in the ETM

2) If the pedal position and throttle position sensors don't match there will be another code thrown by the ETM

What type of scanner are you using? This may be the key to truly finding the source of this problem without tearing huge clumps of hair in the process. A Vida/Dice setup is best with second best being an Autel EU-702

EverRespect · Post by **EverRespect** » 21 Mar 2013, 06:35

The XeMODeX ETM is $500 and you need to do it, especially if you have a white label. If you have over 50k miles, that is 99% of the time going to be your culprit. I have a turbo so I had my mechanic do it and it was an additional 1.5 hours in labor. If you have a non-turbo, it is a very easy DYI. I highly recommend it; it feels good to finally like my car and you will save yourself boatloads of money fixing things that don't need to be fixed and getting taken for a ride by mechanics and/or Volvo dealers in the process. A dirty or defective MAF, ETM carbon build up, or stuck butterfly can cause problems, but it isn't going to throw you in limp mode. Also, the software update does not fix the ETM, it just helps mask the problem so it will run until the potentiameters (sp?) completely rot to the point you get to where you are at: limp mode.