Hello!

Can anyone help??

My Stilo (2002) is showing engine fault code 1222. Because of this, we have changed the throttle body and throttle pedal. Light went out on it's own but is now showing the same fault. Sometimes the fault code shows and there is a loss of power, other times no loss of power but fault code will not go out.
Have done a manual reset to no avail.
Have also checked brake light switch and anti freeze levels as apparently this can also give same fault code and power loss.

I'm really stumped - any ideas??

Thanks very much!

[FONT=&quot]P1222 Accelerator potent. track 2[/FONT]
[FONT=&quot]P1222 Line driven potentiometer 2 [signal implausible][/FONT]


As you've already changed the accelerator pedal then I'd check the wiring between the accelerator pedal K55 and the ECU M10 for loss of continuity. Note that it goes through connector D4 so any poor contacts there or even at the ECU connection itself will give that fault code

Deckchair5 said:

[FONT=&quot]P1222 Accelerator potent. track 2[/FONT]
[FONT=&quot]P1222 Line driven potentiometer 2 [signal implausible][/FONT]

View attachment 81589
As you've already changed the accelerator pedal then I'd check the wiring between the accelerator pedal K55 and the ECU M10 for loss of continuity. Note that it goes through connector D4 so any poor contacts there or even at the ECU connection itself will give that fault code

Click to expand...

Thanks ever so much for this - I will give it a go!
Please keep an eye on this thread as I may require your knowledge again should it still not solve the problem.
You are a star

Deckchair5 said:

[FONT=&quot]P1222 Accelerator potent. track 2[/FONT]
[FONT=&quot]P1222 Line driven potentiometer 2 [signal implausible][/FONT]

View attachment 81589
As you've already changed the accelerator pedal then I'd check the wiring between the accelerator pedal K55 and the ECU M10 for loss of continuity. Note that it goes through connector D4 so any poor contacts there or even at the ECU connection itself will give that fault code

Click to expand...

OK - so we tried the connections between M10 and K55 and all seems to be OK in terms of continuity. Engine fault cleared and now the light is back on again with the same 1222 fault code. Couldn't find D4 - any idea where this is located?

Thanks again for your help, it really is appreciated. Any other ideas as to what it might be?

The D4 connector is below the under bonnet fusebox.

There's a guide (published by Deckscair5) to cleaning it here:

https://www.fiatforum.com/stilo-guides/99828-d4-connector.html

If you've checked continuity from K55 to the ECU M10 then there's no real need to check out D4 as you know continuity is fine at each end

First off, the fault code you have IS P1222 isn't it? I would guess so as you have accelerator to throttle body problems but you mention just 1222 so I thought i'd check

Next step would be to check voltages for supply,earth to K55


at accelerator connector K55
5v supplies on both pins 3 and 5
earth on both pins 1 and 2

If they're ok then i'd trace what two signal voltages K55 is sending to ECU

Not very easy I'm afraid and would require back probing the ECU connector A, pins 43 and 40. I'd check for linear and smooth voltage change with accelerator pedal movemment, it'll range from around 1v to just under 5v

Right, i have checked for voltage at K55 and found no power to pin 3, there is also no earth at pin 1, i have tested for the same at M10 and got the same results.
Am i to guess that this is looking like an M10 fault and are they inter-changeable? i have also cleaned up D4, i think i am now clutching at straws...........

any other suggestions welcome.

Ok, well that will be the fault, there is no 5v supply or earth getting to K55. So the fault will either be poor connection at M10 or M10 isn't putting out the 5v and earth

You could try linking the two 5v supply wires and the two earth wires to K55 as they will originate from the same supply within the ECU and as long as the two K55 signals return to the ECU then it should all work. You could make the links at the D4 connector

Deckchair5 said:

Ok, well that will be the fault, there is no 5v supply or earth getting to K55. So the fault will either be poor connection at M10 or M10 isn't putting out the 5v and earth

You could try linking the two 5v supply wires and the two earth wires to K55 as they will originate from the same supply within the ECU and as long as the two K55 signals return to the ECU then it should all work. You could make the links at the D4 connector

Click to expand...

Your like a God man...

Oh well, it was a good try, i joined the 2 supply's and the 2 earths, cleared the fault and took car for a really good drive, everything seemed fine.
today i moved the car off the drive and hey presto! the engine fault light came on again!
this time the engine was revving irratically and then stalled, i checked the fault code and it showed P0105 MAP/BARO circuit malfunction, i cleared the fault and it seems ok, but have yet to road test.

Any more ideas?

Yes I could write a book on P0105
It was probably just a bad contact at the MAP sensor, different fault, give the electrical contacts some treatment with electrical contact cleaner (nothing else), let it dry and reconnect. Probably just tarnished contacts

Thanks :0) silly question but where is the MAP sensor?

1.6 MAP sensor.
Once you've cleaned the contacts, reconnect then clear the fault codes
Turn ignition on, pause, then start engine, let it idle for a minute, turn engine off.

Then, fingers crossed, you'll be good to go

Thanks again, will let you know how it goes.

Deckchair5 said:

View attachment 81791
1.6 MAP sensor.
Once you've cleaned the contacts, reconnect then clear the fault codes
Turn ignition on, pause, then start engine, let it idle for a minute, turn engine off.

Then, fingers crossed, you'll be good to go

Click to expand...

By the way, you have been a life saver...would have been completely lost without your help so thank you so much!

Do you think the new fault code is coincidence or one that has happened as a result of me messing with the electrics?

It could easily be coincidence, connector just loses contact but worse case, the ECU 5v internal supply is bad as MAP runs off that too but as you gave it good road test before without problems then it could easily be a coincidence

thank-you deckchair5, drove car over 400 miles this weekend and all is working fine.
your knowledge has been priceless.

Well not really, you haven't got my bill yet

Feel free to make a small donation to the forum to help keep us going

Glad it's all working well

Hi Deckchair 5.

Want to tap you for some knowledge.
I have an intermittant dashboard, all dials and lights bouncing up and down, resetting and checking, esp. in the wet.
whats my 1st step, polly bag the D4 connector, or pull the fuse box and see if moisture is getting in? (1.6 estate Stilo 2005)

regards, Navan_Stilo

Yes, as it's happening especially in the wet then I'd be looking for short circuits anywhere on the dashboard supply wiring. Dashboard gets most of its info from can lines from Body Computer but if the whole instrument cluster is going off then I'd be thinking more of problem with power supply to it