Technical Twinair - P0244-62 Overboost solenid valve - Signal compare failure

[Wasted Spark]

New to me 2013 Twinair 4x4. I've really only the driven the car home from collection and then yesterday to a tyre fitter. On the way back from the tyre fitter, coming up a long hill, so the engine working fairly hard, I got a check engine light (accompanied by a start/stop unavailable message). Car continued to drive normally though.

Once home, I plugged multiecuscan in and among some trivial other things, have the code in the title. P0244-62 - Overboost solenoid valve - Signal compare failure.

I've cleared it and it did not immediately return. Tomorrow I'll take that car to work and see if it does come back.

I have taken a quick look through the history of the car and in December 24 (before I owned the car) it was taken to a Fiat Specialist for a turbo boost over pressure fault. I would assume the exact same issue. They replaced the boost pressure sensor. So I guess that is one thing to potentially cross off the list of potential causes.

On the assumption this will come back again soon, what are my next things to test and potentially replace? I notice refurb turbos aren't crazy money so I'm sort of okay if that is the ultimate answer but it would be daft to jump straight to that solution without some lower cost investigations first. Any guidance much appreciated.

 

[Panda IIs]

New to me 2013 Twinair 4x4. I've really only the driven the car home from collection and then yesterday to a tyre fitter. On the way back from the tyre fitter, coming up a long hill, so the engine working fairly hard, I got a check engine light (accompanied by a start/stop unavailable message). Car continued to drive normally though.

Once home, I plugged multiecuscan in and among some trivial other things, have the code in the title. P0244-62 - Overboost solenoid valve - Signal compare failure.

I've cleared it and it did not immediately return. Tomorrow I'll take that car to work and see if it does come back.

I have taken a quick look through the history of the car and in December 24 (before I owned the car) it was taken to a Fiat Specialist for a turbo boost over pressure fault. I would assume the exact same issue. They replaced the boost pressure sensor. So I guess that is one thing to potentially cross off the list of potential causes.

On the assumption this will come back again soon, what are my next things to test and potentially replace? I notice refurb turbos aren't crazy money so I'm sort of okay if that is the ultimate answer but it would be daft to jump straight to that solution without some lower cost investigations first. Any guidance much appreciated.

Before you go down too many rabbit holes be certain of the state of the battery (and that it is charging properly). You will find report of multiple errors on here that ultimately are caused by low voltage in the battery/charging system (start/stop is a classic along with hill hold unavailable). Even if the battery is "ballsy" enough to start the car there may still be issues.

 

[Wasted Spark]

Before you go down too many rabbit holes be certain of the state of the battery (and that it is charging properly). You will find report of multiple errors on here that ultimately are caused by low voltage in the battery/charging system (start/stop is a classic along with hill hold unavailable). Even if the battery is "ballsy" enough to start the car there may still be issues.

Thanks. I'll take a look. It does seem okay and seems to hold voltage but I know the previous owner let it run flat a few times due to a blue and me issue.

I'll take some numbers and report back.

Having done a little reading on this subject though, I note that an awful lot of people have mentioned having this issue having done fast uphill runs where I guess the engine is labouring longer than normal. That is more or less exactly the scenario mine occured in. Unfortunately, so far, I have found very few posts saying if/how the problem was ever sorted.

 

[Eltezz]

I would be looking at the boost pressure solenoid valve. Had a similar fault on my daughter’s diesel Corsa. I took the valve out and tested it - seemed perfectly ok but the fault would return every few weeks. In the end I decided to replace it just to rule it out and of course, that cured it completely. The ECU calls for boost and the valve sticks or leaks slightly so the pressure sensor doesn’t see the required increase and the ECU throws the DTC.

I can’t help you with where it is on the Twinair but it does have one…

 

[Wasted Spark]

Thanks @Eltezz. Interesting....

I've been doing some poking around tonight, not least because I used the car to go to work today and it threw up the error again under similar circumstances so I think it now fair to assume that this is not something that is just going to go away.

So things that I've found:

1. Battery seems good to me. 12.8v before starting the engine. 14.2v whilst running. They look like healthy numbers I think?

2. Waste gate spindle and linkage feel a little loose. I went looking at this based on a few videos I'd seen online showing how bad this can get. I'm not sure that's my issue. There is some play on the spindle but I expected more based on some stuff I've seen/read if that were my problem. Can't really rule it out but since the fix for that seems to be a turbo rebuild I'll leave that as a last resort. I assume it is normal for the actuator to feel spring loaded so that if there is no vacuum the wastegate snaps open? Not really worked much on turbos before.

3. I did a thorough check of the plumbing around the turbo. I found that the large bore boost pipe from the top of the intercooler to the intake has a very obvious split in it. I tried to photograph it. You can see it there in the middle of the pipe running almost vertically. I can't quite tell if it's split all the way through but it doesn't look too healthy!

4. Another observation on the plumbing was that the vacuum line from what I believe to be the boost pressure solenoid valve (as @Eltezz mentioned above) was quite look. The pipe clip was not doing anything so I was very easily able to pull the this pipe off. Could that potentially cause a vacuum leak so the wastegate actuator would no fully close maybe?

I'm holding the line here. And I believe that is the solenoid valve to the left of my hand?

5. I also noticed quite a lot oil misting around this area but it seems there is a lot generally everywhere around the engine bay so not sure there is anything strange going on there.

6. Last and possibly least. I noticed that the ECO button in the car doesn't seem to do anything. It's something I'm particularly bothered about but I'm only mentioning it in case it could give some clue to something else going on.


So where does that leave me? I'm thinking I should just replace that boost pipe. I'd love someone to tell me that's a sure fire cause of this issue but my gut feeling is that it probably isn't. I think, as per @Eltezz suggestion, I might just replace the solenoid valve for the sake of £30 and I should make sure that vacuum pipe is properly connected too.

Anything else I should consider or test before I move onto thinking about that wastegate....?

 

[Eltezz]

Point by point:

1 & 2, don’t worry about those at the moment, both sound ok.
3. This pipe is on the pressure side so you will be losing boost - a big suspect for your problem. Needs replacing.
4. This clip is undone - another potential problem. Either get the tool needed for these clips (a good investment) or get a small jubilee clip to replace it with. That is the boost control solenoid, by the way.
5. Could be related, not sure. Best to clean it up as much as possible, might help in locating any leaks.
6. Does the eco button light turn off when you operate it? It could be that it is working but you are losing all the extra boost via these problems.

Once all this is done you need to use MES to check target boost against actual boost. Also boost values with eco on and off.

 

[Wasted Spark]

Much appreciated @Eltezz.

Boost pipe and solenoid ordered form autodoc.

I'll pick up one of the clip tools for the vac pipe.

The Eco button does nothing. No light, no change. And I'm certain the car is not running in eco mode. I had another one of these cars a while ago and remember how sluggish they feel in eco mode. I would say this one feels as I'd expect in terms of boost.

As you say though, I should monitor boost. Still getting used to multecuscan but I assume that will be in the graph function?

 

[Eltezz]

Interesting about the eco button, I have no idea why that isn’t working. There may be a setting in MES to see if it is actuated or not.

You can look at individual figures but I would add the two parameters to the graph and take it for a short run. I would expect the figures to be within 1-2psi of each other. Pretty easy to set up and good practice for using MES.

 

[Wasted Spark]

Thanks @Eltezz .

Since Autodoc deliveries usually take a few days, I think I'll throw it all back together and take it for a drive later. I'll report back.

 

[Wasted Spark]

Well I've done some graphing.....

This one seemed to be quite typical where actual boost was running a long way under desired boost.

I eventually managed to trigger the EML. That happened somewhere around the right hand area of this following image. Unfortunately I don't know if it occurred when the actual boost was lower than the desired or whether it happened where that little spike is where actual boost spiked just above desired boost as desired boost came right down.

So.....

I assume (correct me if I'm wrong), I'm not getting enough boost generally? And it seems to me, the most likely explanation for that is probably that boost pipe split?

 

[Eltezz]

Unfortunately I cannot read the scale on the left of the screen so difficult to know what the difference is between the low and high points. The jagged nature of actual boost is wrong, should be a smooth line. Can you load check the pressure difference between the two and post values?

 

[Wasted Spark]

Unfortunately I cannot read the scale on the left of the screen so difficult to know what the difference is between the low and high points. The jagged nature of actual boost is wrong, should be a smooth line. Can you load check the pressure difference between the two and post values?

Annoyingly, I can find no means of dragging stuff around so I can see the full scale. I think this might relate to having this on 4k laptop. Though everything else seems to look normal. If anyone has any top tips on how I might actually go about reading that scale, I'd be most grateful!

 

[Eltezz]

Try loading the graph then click on a point and you should get a readout of actual value at that point. Do it somewhere there is a big difference between the two.

 

[Wasted Spark]

Have to admit I didn't know you could do that @Eltezz . Learning fast!

 

[Wasted Spark]

456 mb difference at that point. Which is about 6.5 PSI.

 

[Eltezz]

Mmm. Should be much closer than that. You are getting about 10psi of boost and the ecu is expecting 16psi.

I will try to get a graph reading tomorrow from my Cross to compare with yours to get a baseline. In the meantime you may as well wait until you get your new hose.

 

[Wasted Spark]

Thanks. Hopefully it is just as simple as a boost leak from that pipe. I guess if that doesn't work, I'll need to look more closely at the turbo itself.

 

[Wasted Spark]

Quick update to report a happy ending. The boost pipe sorted it. Car is totally transformed. I'd obviously just not picked up on how little boost it was making before. Feels like a different car now. Thanks again @Eltezz or all of your guidance. Huge help. Hopefully this thread will help others in future.

 

[Eltezz]

Well done! We all like a happy ending. As you say, hopefully this will help others in the future.