Technical Stalling, engine fault and no acc pedal reaction

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Technical Stalling, engine fault and no acc pedal reaction

Tjommer

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Hello fellow stilo owners,

The stilo is a great car with a lot of features, i have a stilo 1.6 3dr from 2002 which i drove for a year without problems.. but now

My car is acting strange lately with fault codes p0105 and p1121 showing up. When i let the clutch come in at 20km/h in 2nd or 3rd gear without touching the throttle, the car shakes and the revs aren't constant. When i press the accelerator pedal nothing happens. I have to restart the car and then everything is fine for a while.

These fault codes have something to do with the throttle position sensor and MAP sensor i read on this forum. About half a year ago i cleaned the throttle body but haven't had any problems until now. Yesterday i disconnected the MAP sensor and cleaned the contacts with contact cleaner, i did the same for the connector on the throttle body(TPS ?). I also did a throttle relearn procedure according to T14's post in this thread: https://www.fiatforum.com/stilo/169469-1-6-no-throttle-limp-mode-ecu.html
When i disconnected the MAP sensor the car wasn't running good. With the MAP sensor connected it's running better but it holds back a little bit.


This morning the car stalled again at low revs with a cold start. When i hold up the revs everything is fine, it only holds back a little bit. The engine fault light is still on.

I did a search on this subject and read something about the D4 connector and the connection between ECU, throttle body and accelerator pedal potmeters. Should i clean all the D4 and ECU contacts with contact cleaner and how do i find them?

Do you think my problem is solved with a new MAP sensor?


What could this be?




Thanks in advance,

Tom
 
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P0105 can be unclear as to just what is wrong as it's warning that what the TB is saying doesn't correlate to what the MAP sensor is saying ie the TB valve can't be open that much for the amount of air flow that the MAP says is going in the engine

The P1121 gives the game away and is much more useful and warns of intermittent high voltage from throttle position sensor (TPS), the ECU doesn't know where the valve is positioned so it doesn't know which way or how much to move it so it goes into safe mode

A bad MAP won't cause the problems you're experiencing, the ECU will just flag a bad MAP and carry on as normal making intelligent guesses on the air going in the engine but a bad TPS voltage will cause the P1121 and resorting to safe mode to prevent damage

When a fault code is stored then it also usually stores the freeze frame data, a snapshot of when it occured, and what the ecu spotted and all the conditions at the moment when it happened. This pinpoints the problem
fault codes after wet start ok afterwards nov 09.JPG
If you gain access to someone who has a program that can read the freeze frame data this helps greatly


Now is it in the TPS or the wiring from the TPS to ECU?

What I would do is disconnect the TB connector,


throttle body connector pinout.JPG
TB pinout
pull back the inlet pipe from the TB
1.6.jpg
and carefully move the butterfly valve quite a few times whilst checking the resistance of the 2 TPSensors (you donlt have to remove the TB like this). Very difficult to spot a blip as it's an intermittent fault but you're looking for nice smooth and steady change of resistance through out the range on both tracks. You'd need a good connection though with crocodile clips and not just holding a multimeter on the connectors. Just like an old volume control on a radio which crackles and produces noise, these TPSensors are the same.
throttle body sensors trace.JPG
This is how they look throughout the range when they're connected with a 5v input from the ECU.


Then i'd clear fault codes and see what happens
 

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Thanks for your answers and fast responses! (y)

Yesterday i cleaned the D4 connectors with contact cleaner, this makes no difference..


Monday i'm going to the garage for an ECU update and the freeze frame data, i also ordered a U380 fault code reader from Ebay so i can check/clear the fault codes myself.

I'm also going to buy a multimeter and check the resistance on the throttle position sensors..

I will post the results in the afternoon.


Thanks again!
 
I measured the resistance on the throttle body this afternoon. At the first sensor (numbers 1 and 2) the resistance increased from 1,6 to approximately 3,2 kOhm. At the second sensor the resistance decreased from 3 to 1,5 kOhm. Both with steady changes.


This afternoon i lost the throttle a few times, started the car again and a minute later i lost the throttle again and so on..

When the throttle is available, the respons is sluggish and feels like it's holding back.


So the MAP sensor and throttle body aren't causing my problems i think, i have to check the wiring to the ECU and throttle body but how do i do this??

Would an ECU update solve my problems?
and is it possible that the accelerator pedal itself produces wrong values?


Thanks for your help


Greetings
 
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Would an ECU update solve my problems? No
and is it possible that the accelerator pedal itself produces wrong values? No, not a P1121 DTC

i have to check the wiring to the ECU and throttle body but how do i do this??
Yes, that's what i'd do but you're getting into some intricate stuff now
Let's assume the TP sensors are working fine and putting out the right info, your ECU is saying "I'm not seeing that" so you want to test things out as close to the ECU as possible

throttle bdy circuit.JPG
So TPS to ECU wiring diag shows ECU connector B

ecu 1.6 location M10.JPG
See the ECU M10B connector that's the one nearest the battery.

CIMG2154.JPG
Now ideally you want something exactly the same dia as the ECU connector pins as you don't want to jam something in there that will make the pins a sloppy fit afterwards.
ecu M10 connector B pinout.JPG
Find the relevant pins, connect up a multimeter and then see if you can see any problems with checking the TPS resistances from there.
 
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Thanks for your support Deckchair..

This is complex matter, it's an intermittent fault so i have to measure it while the problem comes up. When the car is running idle i have no problems, the problems come up when i'm driving.. hmm difficult to check the resistances at that point.

Are these values also visible in the freeze frame data?
 
Yes, if there is freeze frame data then it will say exactly what the out of limits value was that triggered the fault code along with the other parameters that made it an implausible figure

It isn't easy at all but i would want to find out which side of the ECU M10B connector the fault lies ie
between the ECU connector and the TB sensors? or
between the ECU connector and going into the ECU?

I'd first check if there's any problems short circuit/open circuits between the TB connector on the 4 wires for the TB sensors and the ECU M10 connector
 
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It's getting stranger every day..

This afternoon i visited the fiat dealer for a diagnose, freeze frame data wasn't available..
The fault codes that came up this time were: P0101, P0105, P0110 and U1706

No faults on the throttle body or sensors ?

I have to say that since i cleaned the M10B connector on the ECU, i haven't had any stalling problems or accelerator issues since then. So i guess the cause was a bad connection at the ECU.


How can i have an air leakage in my intake manifold? the MAP sensor i reconnected fitted perfectly with a good seal so this can't be the reason..
 
That's good news then, looks like it's a poor contact at the ECU connector. Well done:)

[FONT=&quot]P0101 Mass or Volume Air Flow Circuit Range/Performance Problem[/FONT]
[FONT=&quot]P0105 Manifold Absolute Pressure/Barometric Pressure Circuit Malfunction[/FONT]
[FONT=&quot]P0110 Intake Air Temperature Circuit Malfunction[/FONT]
These P01xx codes may be when you were spray cleaning the MAP sensor and its integral air temp sensor. Maybe didn't wait long enough for it to dry. See if they pop up again

U1706 is can bus node NCM (node controlle machina) = ECU to
NFR = node Freni =ABS. ABS unit has a grotty earth connection called C12 all of its own which has caused problems in the past.
ABS unit earth C12 Abarth.JPG
Look for an earth eye type connector from the ABS unit to the car body
 
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Thanks Deckchair, what should i do without you :)

I'm going to clean the C12 earthing connector for the ABS system.

At the moment the fault codes are cleared an the engine fault light is still off but the car acts like it's clogged or something. The idle isn't constant (+-200 rpm) and when i press the accelerator pedal it takes a while before it gets going..


Any idea what this could be? air leakage, lambda sensor?
 
The idle isn't constant (+-200 rpm) and when i press the accelerator pedal it takes a while before it gets going..
I take it you've cleaned the throttle body valve as described in the Stilo Guides up above?

Do you have the means to view your lambda sensor output voltages?

If you have laptoip it would be well worth buying a VAG COM type cable and using the FiatEcuScan software so you can see what's going on. It owul dbe good to know that the correct engine temp is being seen by your ECU. You could also check the accelerator pedal input and response
 
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I cleaned the throttle body a half year ago with brake cleaner, could it be filthy already?

Just bought a U380 code reader from Ebay and i don't have a laptop so it's difficult for me to check the lambda sensor values..

Haven't seen any fault codes for a few days now :cool: so i'm happy for now. When the problems get worse i will get a laptop and VAG-COM cable so i can check everything myself.


U1706: Does the car drop out/stall with this fault code?
 
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Hmm strange..

The problem came back this afternoon. When i let the clutch out in 2nd gear at low speed (+- 800rpm) the engine fault came up. The problem only occurs at low revs it seems.

Because of the inconstant idle and varying rev increase during acceleration i have put some injector cleaner in it yesterday..


The fault code that came up was P0101, MAP sensor range?


What else could i try?
 
If you've had a fair number of P0105 and now getting P0101 then it may well be time for a new MAP sensor. They're a kind of membrane like a trampoline and as it moves with air pressure/vacuum then the resistance alters but with age they tend to get less flexible and the resistance can jump. It's such a small range too from 0.5v to 4.5v max output that it doesn't take much for things to go wrong

Symptoms are "driveability" Ha! What's that? Well jumpy running at low rpms, sudden surge in power with just a little gas or higher than expected mpg. Engine dying unexpectedly. Quite simply the air/fuel mixture isn't right sometimes. Most of the time it is, then blat, doesn't compute with throttle opening

Could always be a bad connection there at the MAP of course but if it's happening too often then something is up.
 
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Have read this post and the symtoms are exactly the same on my 1.9 jtd. So think i may give the above a try. It also seems when its a low idle speed that the accelarator cuts off in to safe mode, turn off key and wait 30-40 seconds and then it will drive again maybe for a couple of mile or sometimes days. Will try get some fault codes asap.
 
I have managed to sort out my problem, There was a loose wire at the ECU plug, Have cleaned the plug with contact cleaner, and sorted out the loose wire. Seems to have sorted the problem :)
 
Hi guys, i'm back with the same problem... :mad:

The car drove fine for almost a year but now it's having the same problems all over again. It seems like the problems come up when it's wet outside and when i'm driving on a bad road with a lot of bumps etc.

A month ago i cleaned the D4 connector and ECU connectors again, this didn't help a lot this time as the problems came back after a few weeks.

The fault codes the car gives me are P0101 and P0105, i fitted a new MAP sensor a year ago, could it be broken already?

What do you guys think?
 
The P0101 and P0105 point to your MAP being out of range or a cricuit problem. With a P0105 then the car won't clear the fault on its own, once it's flagged as bad then it ignores it until you clear the fault code

Test by back probing your MAP sensor. Should have

A white Earth
B white/ Air temp arouind 3.3v at 15C
C grey 5v supply
D green map signal -around 4.5v with just key to MAR maybe down to 1.5v at tickover

NB the Fiat wiring diagram is wrong. It shows the 5v supply to be at pin D whereas that's the MAP sensor signal. 5v supply is grey wire on pin C

MAP sensor correct wiring pinout 1.6 K43 .JPG
Best to go from this pinout diag for MAP sensor K43 which is correct, showing 5v supply on grey wire pin C and MAP signal on pin D green wire

As you're getting faults on bumpy roads and wet weather then I'd be looking for a poor contact connection
 
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Thanks Deckchair (y)

Do you know where i can find the K47 connector ? so i can clean and check this connector for bad connection(s) and wrong values from the map sensor.

Since i recently put in a new MAP sensor i don't think it produces wrong values, i think i have to look for problems in the wiring and connectors. But i'm going to check the values anyway to make sure..
 
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