Hello

My scan tool reads this error. The car dies sometimes totally randomly and MIL pops up with the code p0105.
How does one know if its need a firmware upgrade or its a faulty sensor ?

Does the fiat examiner software work with elm327 interface?

P0105 is MAP sensor but it doesn't mean you need a new MAP sensor. However it does mean your car is now ignoring the MAP and probably drinking fuel.

Do a search and you'll find what you need to do to tell the ecu to stop ignoring the MAP and save yourself a fortune in fuel

Hello
Ive searched the forum before posting.
Some posts say you need new firmware to fix this.
There isnt much info on proper diagnosis for this.
I have put it apart and investigated cable connections from the sensor to the ECU and everything seems fine. The freeze frame for the error looks like this


Do I need to visit fiat garage to sort this one out ?

That short term fuel bank is just dumping fuel in there at 67%. LTFTB is at 0 so i guess you just reset the ecu or cleared a fault code?

Do I need to visit fiat garage to sort this one out ?

Probably not. You're going to tell your ecu to not be so choosy and pretend you have fitted a new MAP sensor.

Disconnect the MAP sensor and then start the engine, it'll bitch a bit but then turn it off. Clean the map sensor electrical contacts with contact cleaner, let it dry, reconnect. Now turn just ignition on and clear the fault code. Turn ignition off. Now restart the engine and see how you go. Drive normally to let the engine relearn the best settings now.

Thanks for your replies.

I will go and diagnose the car anyway - its about 10pounds here so that aint so much and maybe they figure out something more about the problem.

I kinda dont believe 'fooling' it would be any sucsess. There are strict scenarios written to the computer that diagnose this as p0105 and I really doubt that trying to fool it like a child would work because after every reset and even after some milage the ECU runs the same tests again and again.

It is bad that there arent any fiat PDF files over internet with diagnostic procedures like the ones I was able to find about Toyota where they say exacly p0105 = voltage spike on the map sensor wiring - either pressure =0 or above 130 etc.

Yes there is a software update for this which also smooths out the (often uneven) idle at same time.

I kinda dont believe 'fooling' it would be any sucsess. There are strict scenarios written to the computer that diagnose this as p0105 and I really doubt that trying to fool it like a child would work


Well, this is my Stilo with a P0105 in May 2008, not a peep since improving the connection and telling the ecu to "look again"

after every reset and even after some milage the ECU runs the same tests again and again.

No, once this code is hard stored in the ecu it ignores the MAP sensor from there on in until you clear the code. It doesn't do any further tests even if you cure the "fault". It expects you to fix the problem and clear the code and won't do anything else until you do. That's what the above routine does, simulates a new MAP being fitted and resets the fault codes and fuel trims. Whilst the MAP sensor is being ignored you have a very uneconomic fuel rich running engine

Hello

Well I visited two fiat authorized service centres and none of them had any software update for this available :S.

What wonders me is that the engine doesnt do the error 'just like that' I have noticed it having trouble maintaining steady rpm occasionally.
I dont have a rpm meter on the dash but I can see the lights go down and up while the engine is idling.
The error pops up when this waving leads to engine stop. After that Its very hard to start it for a short moment - bam MIL comes up and it starts.

Note that the 1.6 has 223kkm done and this problem havent occured before thats why I still think a soft update wont cure it. Why would a firmware problem show itself after this milage ?

I'd say you have throttle body connection/communications problems. The P0105 is saying "implausible throttle feedback for what the MAP is saying" ie the throttle valve can't be where it says it is when the MAP is saying that amount of air is entering the engine, something's wrong - bam - P0105

I'd investigate whether you have poor throttle body connection either at the throttle body or at the ecu


I dont have a rpm meter on the dash
Why? Is it broken?

but I can see the lights go down and up while the engine is idling
That's a very poor idle then and not so good battery power?

Note that the 1.6 has 223kkm done and this problem havent occured before thats why I still think a soft update wont cure it.
Is that 223,000km? and yes,i agree, i don't think a software update will cure your idle problems

Can you take live data readings with engine idling of
throttle valve %
MAP sensor
O2 bank 1 sensor

Hi

Thanks for trying to help me with this.
I have looked on lambda read outs and map sensor before.
It looks like the map is working fine - shows about 90kpa while off and variates around 40kpa +- 20 as I press accel pedal and is stable on 46 during idle. Lambda jumps like it should be.

I havent investigated poor connections to the throttle body as you mentioned just the MAP sensor connections and the ECU plugs which seemd in perfect shape.
The low lights going down is indeed the RPM going really low. sometimes between gears you can feel youre actually 'starting' the engine because rpm is so low as it would be dead.
This valve is 100% computer ran so there arent any 'low rpm' dongles that push it open when needed as it was done in mechanicly driven ones?
Should I also attempt to clean it ? The MIL would suggest something more than dirt problem. Wouldnt want to screw this anymore than it is now.


I dont have rpm on the dash because its a doblo and they forgot about it along with ABS but it does have AC and electric windows
Otherwise the 1.6 is exacly as the one in stilo.

This valve is 100% computer ran so there arent any 'low rpm' dongles that push it open when needed as it was done in mechanicly driven ones?
That's right, the throttle valve is all computer driven but if the valve gets clogged with grease and dirt and can't move freely then it can't do the fine adjustments required to hold a steady tickover

Should I also attempt to clean it ?
Yes I would do that right away. Just do what it says in the Stilo Guides

What is the fuss with braking the servo mechanism if you force push the valve?
Somebody posted that in comments for the guide.
Will attempt to clean it today but would like to be sure before i do it

Treat it the same as you would your favourite girlfriend, you don't force anything. It's a fine geared motor so you do so at your own risk, it's only £300 if you mess it up

Do a search and check through how to do a throttle relearn procedure before you start

Hello

I had to remove the valve from the car becuase doblo has poor access to it.
Was very simple with proper tools.
I cleaned it with a paint brush and extracted petrol - dont really know the english translation so fix me if you know the word, just like Ive done with carburators so its nice and shiny.

Results are really amazing. No trouble starting on cold, low rpm returned to steady and it feels very smooth. But the most important part - the MIL havent returned after 400km since I cleared it from errors and the ECU reports all tests were completed.

Im very surprised because I hoped for p0105 to go away but I had another problem with p0420 about the cat converter. Was ready to at least see "pending DTC" with the p0420 but it wasnt there.

Thanks for your help with this. Retards from fiat service would drain the last penny from me on this as they wanted to disconnect LPG ECU etc...

Good for you!
The P0420 is largely because your engine was overfuelling so much that your catalytic convertor was struggling to cope so you should see much better economy now too

Hi

Sadly the p0420 returned after 2kkm but bypassing that (it might be that i need a new one after 230kkm not very nicely serviced life) there is one thing thats still not 100% right.
Shifting fluently is still a bit of a challenge to make it fluent. And Ive also noticed that when its under very very low load for example on 4th gear you get the feeling its misfiring.
The problem between shifts are more noticable on LPG. However Ive done 70% of that milage on petrol.

The trim changed to +10%.

PS. I was ready for the cat error to come up again tho the period changed a lot after that cleaning. I knew it would come up as the second lambda sensor is jumping a bit ot 0.7v its like its stable on 0,28 for maybe a second then pop to 0,7 and this is repeatably (did switch lambdas already and these readings areng 100% as Ive havent used any oscilloscope just the OBD thing). From what I read this indicates catalyst problem.

If you have any clues for me it would be very nice to hear from you.

Thanks for your help!

The P0420 is signalling things are not right when comparing the pre cat and post sensors readouts. Most likely, as you've seen, your No.2 post cat lambda sensor is slow to react after that kind of mileage. This shouldn't give any drivability problems though. Lambdas can get unreliable anytime after 50K miles

LPG? Well the engine isn't designed to run on LPG so absolutely anything can happen in driveability when using LPG so I can't help you if you experience problems with that

I will deal with that p0420 with lgp emulation for 2nd probe. I guess its more than possible that cat isnt so well anymore.

As Ive said the problem occurs on petrol too not only on LPG. I always try to 1st make it work well on petrol before I even think about driving LPG.

About a year ago when I was wasting money on fiat garages the code reported problem with ignition coil second cylinder. Since I have the ODB interface that error never turned up.

My question is how does one check the coils as the car is indicating some misfire problem on very low loads and stable speed. Will swap plugs also...

CATS AND O2 SENSORS
Cats are pretty tough and are often changed needlessly. OBD watches the readouts from front and rear O2 sensors and is programmed to signal odd things happening and fires up a P0420

Re the misfire
OBD is pretty good at detecting a misfire so check to see if you have a fault code like P0301 (cylinder 1 etc) BUT be aware that "misfire" is exactly that, it may not mean anything wrong with the ignition eg coil or plugs, it's more clever than that, it detected a misfire -a jolt if you like - on that cylinder that happened more than a few times. Poor fuel/air mix will do the same

p0105 came up at random after about 3-4kkm this happend right after clearing p0405 before that It worked quite a while without p0105.

Could this be related to exhaust valves not holding properly plus hydraulic tappets rattling a bit ? I mean they rattle like hell when started in the morning then its more silent.