Right, Have had the brake light switch replaced and the fault remains P0703 and wont clear and the garage have said it might well be a ecu fault as the boost fault is still there too but only after i give it some stick.

Would cleaning the D4 and the other connectors help as have bought some contact cleaner from hafords tonight. What about cleaning the contacts to the ecu which i assume is the box sort of front left in the engine bay near the header bottle.

Any other suggestions as it is really really P***ing me off now and any ball park fiqures for the ecu if it is that. Im guessing if the ecu is on the way out that would also be why there is a boost valve error too?????

Thank you.

Have you checked out that MAP sensor yet - very common.

Even a clean might sort it

No, will do tomorrow. Any thoughts on the other issues.

You mean:

P0703 = Torque Converter/Brake Switch B Circuit Malfunction

I've got no idea but it might be worth considering that you've had this error for a long time i.e perhaps it doesn't affect the car :chin:

Think I'd be considering that as the fault refers to an automatic gearbox and yours is manual, there may be a problem with yani's software. There's a bug report section, and a forum for such problems on his site.

Yes but this is what Huttons have come up with too this afternoon.

So its a fault code that wont go away and noone knows and i dont know how long its been there for.
The other problem is this boost valve code which still wont go away even with the new valve. Could there be a split in the pipe work to generate the code.

Im really really stuck as to what else to try. I will look at all the boost pipework tomorrow just to see, i will put the old one back on to see if that makes any difference.
The P0703 fault code is what huttons found today and is the code that cant be got rid of, the boost valve resets and comes back.

And i only got the fault code for the boost valve after disturbing the d4 conector and the one next to it and i thought i would clean them oh and cleaning the egr valve.

Just want to double check something,

The overboost valve and the two pipes that attach to it,

The outside pipe go's from the engine to the valve and then the inside pipe go's to the turbo.
Thats how it is on mine.

Is this correct, can anyboby double check please.

Thanks

William

The vacuum feed goes from vacuum reservoir at back of engine.

The outlet pipe goes to the actuator.

If you lose vacuum at any point then you will notice quite a power loss followed by error logged at ecu (the ecu wont be able to detect a slight leak even though the driver will).

I had a leak on the curve just before the actuator (needed to be under the car to even see it :bang: )

The MAP sensor get involved because if it produces a false high pressure reading then the ECU backs off the VGT valve to try to compensate.

Think the map must be faulty then, took it off and cleaned as best as i could but hasn't made any difference at all.
Interestingly enough when the car is at idle the boost valve is at 75% and then drops the more boost is produced but when the error code comes up the boost valve is at 30%.
This happens both with the new valve and the old one. Is this normal being at 75% at idle or is this telling somebody something. Anyone got time to see what their Jtd is at idle so i could compare results.
Also on the pro-gramme it has this; function indicates the OVERBOOST strategy On/Off status. NOT ACTIVE Should this be ACTIVE.

Going to phone Huttons on Monday to see how much the MAP sensor is and continue from there i think.

Well hopefully thanks to Shop4parts i will have a new Map sensor (part no S4P3866) For a very good value £29.25 delivered.

So fingers crossed this fixes the car and thats the end of it but im kinda doubting it as the cruise control is also still not working but all the on/off switch, speed up/down, resume button all working but light on dash still not wotking either and im thinking all linked to the same ecu.

Well thats it................................... i am completely and utterly fed up with my car.

Phoned Hutton's on the of chance of them having a Map sensor and yep they did so i drive all the way up there get it, drive back down the road a bit to a lay by and fit new sensor and clear the faults and within 2 miles the fault is back.

So too recap....................................,

1 boost valve, which works as i can hear it when testing it with the fiat ecu software,
1 Maf sensor but questionable if it was that,
1 Map sensor but again no difference.

So next thing is i guess have the turbo off to see if the VG bit of its working. When argonought said about bypassing the boost valve and holding the two pipes together the actuator moved but haven't tried it since.
What else is there and is this now looking like a ECU problem.

Thanks.

That's real bad luck and sorry for giving bad advice

When I had a problem with mine, like you, I thought it must be a big problem with the turbo itself but as you know it turned out to be just an intermittent split in the overboost tubing (took 3 hours to find :doh

... so hopefully it might still be something simple.

Well argonought your advise was spot on, I have been out and i think the whole issue has been a split pipe somewhere as i have pulled pipes of from the back of the engine where the boost pipe comes from and had a look and pushed them all on again and would you believe it...............

Its running great. I went down to the local agricultural engineer and have asked him to get me 2 meters of the small bore pipe and a meter of the slightly larger size to go from the boost valve to the actuator and i will change all of the pipe work and hopefully we will have a result.

I also went for a drive and gave it quite alot of stick and where it has normally gone into limp mode it didn't.

I'm just thankful for everybody's help:worship::worship: as its been one of those bl**dy annoying faults that could well have cost a fortune had it not been for help from you guys at Fiat Forum and one of the reasons that the Stilo will be replaced by another fiat in the next few months.

THANK YOU.

Well replaced all the pipes this morning and have just done 350 miles and not a cough/stutter and normal service has been resumed.

Cost £10 for the rubber piping.