Hello,

I have a 2001 V70 2.4t with a difficult to diagnose Check Engine Light.
It has recently had new front struts and mounting hardware, atm fluid replace, oil+filter replaced, and ETM sensors replaced with Xemodex no contact ones (by me, Robotics Technician here). The Vacuum lines on the turbo have been replaced with IPD silicon tubes and there are no leaks that I can find with carb cleaner, the TCV is working as is the wastegate. I have replaced the MAF sensor and the spark plugs, new air filter and boost gauge. I just today re flowed the ABS solder joints in case they were the problem, but to no avail.
It's posting OBD2 codes p1618 and p0722; general Transmission related CIL and VSS signal. Looking at it's history it's been posting these codes for a couple years. The orange ! triangle stays on and "transmission Service Required" comes up when the CIL comes on. If I reset the codes they repost as engine hits temp and the OH module posts. This is the Oxygen Heater Module (no idea what that means). As soon as it hits ready status i get the CEL and transmission service required.
Took it to volvo, had them scan it with VIDA. They list;
ECM-530D MIL on due to TCM
TCM-001F VSS signal missing

I tried reversing the speed sensors locations to see if different codes came up, but got exactly the same ones after clearing them and driving it. It seems like the sensors are not the problem. I can also see them returning a signal when backprobed with a multimeter; about 200mv at idle speed from both of them when in drive or reverse. I assumed it was ABS and reflowed it today but as soon as it was open and I looked with a magnifying glass I couldn't find anything that looked bad or cracked. I soldered because other people have failed to see something and been successful, but I saw no change.

Driving wise we still see a tiny bit of hunting at idle, between 660 and 760 rpm it seems.
What do you guys think? I NEED to clear this check engine light so as to get the car transferred and registered under Ontario's insane Drive Clean program. I ordered a VIDA/DICE but that wont be here for a couple weeks. I know I'm shooting blind without it, should have got it first, but we live and learn.

 

I'd just suggest doing a careful fluid level check (much, much easier said than done however). A low fluid level can cause a host of strange issues and diagnostic results (I had an axle seal leak and got to test this premise a couple times). ;-)

You'll no doubt be able to check that VSS signal once you get your VIDA/DICE unit, but it seems like reversing the speed sensor wiring would rule out the sensor itself.

As an aside, it's really hard to imagine that a TRANSMISSION error code would prevent registering a vehicle, but I've long since learned never to underestimate the ineptitude of any bureaucracy!

 

Thanks for the advice.
Checking the TCM connectors is now on the list of things to try. Ill order the part remover.
Ill recheck the ATM fluid, but I recently changed out the fluid and checked the levels, they appeared good. The sensors are known good up to their connector I guess, so it could be a wiring problem after that between them and the TCM.
The new deal in Ontario is that any CEL at all disqualifies it from an etest sticker. No option to do an actual in pipe test at all; you have to pass with the cars internal sensors being relied upon. It's insane. On the other hand if it's just your two year renewal and you fail the test due to a CEL, they can at that time force you to put 450$ and no more into your car in an effort to correct the light. Once you have receipts for 450 they have to give you a one year conditional pass sticker. You can get one of those every year, each time only putting in 450$ max if you want too.
HOWEVER, to register a car that you buy from someone with one of these conditional etest stickers, you must have it retested and pass, and there is no conditional pass. So that means you can buy a car from someone with the CEL on, but then to get it registered in your name you have to get the CEL off no matter what it takes. It's insane. It destroys the equity in hundreds of perfectly good cars, while allowing for a 450 dollar loophole to totally let cars with insane problems on the road. The tailpipe test was INFINETLY better and more accurate, and allowed for the properly working cars to pass and the broken ones to fail no matter what the sensors said, but Ontario is more interested in forcing people to buy brand new cars then it is in being environmentally progressive.

 

I am a bit confused by your post. Sorry I am not a mechanic I am also an American not Canadian. But it sounds like when idling you are getting a RPM surge. Sounds also like it is some kind of emission test you must pass to clear register with your province. I am not sure what you are talking about with the Transmission. If the transmission was junk you would get a slip between gears on these era cars.

I think what might be happening and is common amongst turbo cars. Is your PCV system needs to be cleaned or replaced. Which if I understand you right for emission or smog or whatever you call it sounds about right. You seem like a better mechanic than me. But here is a good video on how to check for basic issues if the PCV system in wrong.

 

My PCV system is good; no smoke and a good vacuum on the oil cap.

I'm in Ontario. To register a car here you need a "Safety" and an "Etest". The safety is a mechanic inspection, the etest rules changed in the last few years, it is now a reading of your cars OBD2 system sensors. If there are any check engine lights on then you fail the test and cannot legally drive the car. This is insanse because your OBD2 system cannot be relied upon; many people experience sensor glitches or failures that are perfectly normal for daily car use, but would cause you to fail this test and maybe put thousands into your car tracing down the glitch.
We don't get slip so we are hopeful it's a sensor error not a transmission failure. Seems like we'd get more codes and driving problems if it was the tranny. As it is, the car drives great, if you floor it it goes like a bat out of hell.