throwing in the towel perhaps

Post by **rmmagow** » 22 Jan 2013, 05:37

That does sound like the ECT. I have another car that drove me nuts like this and the temp sensor was the culprit. That car was (and is) an 89 with no OBD so it was quite a challenge to find. I would do thermostat and the ECT

warcraftjunkie · Post by **warcraftjunkie** » 31 Jan 2013, 22:23

Well, I changed the Thermostat and ECT today with no real change in behviour of the car. I reset codes and the same ones came back within a few minutes.

The Thermostat was definitely bad as it was stuck open, so it's not an effort wasted. I went to the salvage yard where they got in a 2000 S80 with the same MAF sensor as my 99 V70, put it on, and made no difference. It probably could stand to be cleaned so I'll give that a shot tomorrow. Currently the codes I'm getting from the generic reader at Autozone are

P0030 (Heated Oxygen Sensor Heater Control Circuit Bank 1 Sensor)
P0236 (Turbocharger/Supercharger Boost Sensor A Circuit Range/Performance)
P0237 (Turbocharger/Supercharger Boost Sensor A Circuit Low)
P0102 (Mass Or Volume Air Flow A Circuit Low Input)

Only other sensor left in this equation would be the front O2 sensor... so that'll be next.

warcraftjunkie · Post by **warcraftjunkie** » 02 Feb 2013, 18:12

Ok, today I put in a MAF sensor from a donor car at the Pick-N-Pull and didn't get any better results. Of course I have no idea if the donor MAF is bad.

So I decided to chase down the Front O2 sensor trouble code. After struggling to get the car up on ramps, I crawled underneath to get a look at the sensor. I was going to pull it and then clean it, but as I was tracing the wire I found that it was disconnected. I'm going to assume who ever put this sensor in, didn't lock it with the sliding clip. I reconnected it after constructing a platform to lay on top of the engine so I could reach down into the depths. I reconnected the battery and took it for a spin to Autozone. Sure enough my P0030 code is GONE! Hurray for at least one victory!

With that said I'm still getting P0102 (MAF), and P0237&P0236 (MAP Sensor). If I reset the codes, they come back immediately without even turning over the ignition. Occasionally it will also throw a P0453(Evap).

warcraftjunkie · Post by **warcraftjunkie** » 04 Feb 2013, 10:39

So would it strike anyone else as odd that I get P0236, P0237, and P0102 immediately as key gets to the run position, but before I crank the engine? Its as if it's sensing those components (MAF and MAP sensors) are missing?

I've also noticed that after a battery reset and I fire it up, those codes are there.. check engine light is on, but no ETS light... I can drive like this for a long time, but if I turn off the car and start it back up, about 10 seconds later the ETS light comes on and the performance is markedly worse and more likely to stall out.

I can replicate this 100% of the time.

Can P0236 and P0237 be caused by the TCV? all the research I've done indicates that replacing the MAP sensor is the correct remedy. Of course I've checked the turbo inlet hoses and seem to be in good health and properly seated. I have sprayed brake cleaner and/or starter fluid along the different intake hoses to see if I can cause the engine to stumble from the cleaner entering the air stream.... No stumbles so I'm fairly confident my hoses are in good shape with no vaccum leaks.

warcraftjunkie · Post by **warcraftjunkie** » 06 Feb 2013, 15:18

Any thoughts on this last post?

Post by **northernlights** » 07 Feb 2013, 15:56

I'd say it's a real head-scratcher. I went back through the last few posts. It looks like:

1) It sat until early January, and mysteriously ran fine on a cold day. You observed that the temp gauge didn't come up to temp.
2) You replaced the thermostat (which was stuck open) and the ECT, and nothing good became of it.
3) You put in a donor MAF with no effect.
4) You consistantly get MAF and MAP codes, and sometimes ETS.

Way back when, I was suspecting a bad ground at the ECM/TCM. Were you able to verify the grounds were good? For that matter, is the battery properly grounded?

I've seen poor grounds cause all sorts of phantom problems especially when there are low voltage signals. I was involved with a boiler project years ago that required a bunch of extra, seemingly unnecessary ground wires to make a flame sensor work. I believe that thing induced a voltage in the presence of fire, in much the same way that an O2 sensor does in the presence of oxygen. As crazy as it may sound, add a few extra ground wires between offending components and make sure that somewhere there is a good connection to battery negative.

warcraftjunkie · Post by **warcraftjunkie** » 07 Feb 2013, 19:51

Thanks for the reply.

I double checked the grounds back in December just before letting it rest for the holidays. I was able to check the two ground points on the back near firewall, driver side strut tower, underneath the battery tray, underneath passenger headlight. All those checked out good. I know there's at least 2 more ground points underneath the engine that I was unable to get to because of the snow on the ground and my lack of desire to lay in it.

I even outfitted a temporary supplemental B+ cable from Battery to fuse box for a day to see if that helped since I couldn't see any corrosion on the tips of the B+ cables...didn't want to strip back the sheath too much.

We are getting another round of snow here tomorrow, but if I can beat it, I was hoping to step back to basics and take one more look at the vaccum and turbo pipes. I know I sprayed them with fluid to see if I could cause an engine stumble, but can't hurt to take another looksee.

Doing some other reading I see people having some of these same symptoms with a failing CPS... however I would think that I would get some other codes other than these 3 that just won't go away. I'm still leaning heavily towards an electrical wiring issue. I'm horrible at reading schematics... Anyone know if the MAF and MAP ground out to the same point?

jazz2469 · Post by **jazz2469** » 07 Feb 2013, 23:10

I have a c70 that's doing all the same but its only my check engine light that's flashing and I'm dieing for some help got any ideas for me try? I've been thinking about droping a chevy motor is this dam thing lol

warcraftjunkie · Post by **warcraftjunkie** » 18 Feb 2013, 07:54

2/16/2013 - pulled spark plugs and cleaned them up. Found quite a bit of carbon build up; most likely due to running with the Front O2 sensor unplugged fr 8 months and the MAF sensor unfunctional for a little while. Found large amounts of oil on the plugs of Cylinders 1 and 5. After cleaning up, my ETS an check engine lights turned off and haven't returned yet.

I'm currently running the MAF sensor from the donor car as it seems to be working. I'm not going to count this as a success till I run at least 3-4 tanks of gas with no check engine light.

I plan on buying some new Spark Plugs and a can of Seafoam to clear out the injectors, intake, etc... it ran rich for so long that I'm certain it can only help.

EverRespect · Post by **EverRespect** » 18 Feb 2013, 08:32

Wow, you would expect a Volvo dealership to be expensive, but you would think they'd at least be honest. Sounds like your dealer is a con artist. This might sound stupid, but have you checked yoyr nttery cables and terminals? I once left a car for dead after a mechanic diadnosed a $1000 repair for a similar problem on a Mazda. Car sat in front of my house for a year until I got desperate when another car broke down. Had to change the battery to start it and noticed corrosion so I replaced the terminals as well. Car fired right up with no problems. About once every few months, the bad idle will come back. A few whacks at the EGR valve with my ratchet takes care of it.