Hello

I have a P1220 code on my car. (Fiat Stilo 1.6 16V)

When I start the engine from cold everything works ok until the engine gets warm and the temperature guage is at the center.

Once warm, the engine rpm would rise to around 2000rpm and the throttle pedal would stop responding.

If I switch off the engine and switch it back on, the throttle starts responding back fit say 20secs to 2min then same issue occurs again.

Any help?

Disconnect the oxigen ( lambda ) sensors and watch what will happen.

I dunno... lambda problems are usually related to the signal they send.. so they're not usually temperature dependent... and switching the car off for a few seconds wouldn't make a signal problem go away.

A 1220 error is the Throttle Position Sensor.. so first job would be to take the throttle body off and clean the b'jeseus out of it (taking care not to damage any probes or sensors inside the body) and then removing the TPS, making sure it's clean (use electrical contact cleaner) and moving freely. Also have a look at the wiring to the connector.


Ralf S.

At least his temperature gauge works ! Lol

Thanks all for your prompt responses. I should have responded before now but had a medical emergency.

cliffy71 said:

At least his temperature gauge works ! Lol

Click to expand...

:-D Lol. That and the speedometer are all that works normally in this car. It's a pain in the *ss.

Ralf S. said:

A 1220 error is the Throttle Position Sensor.. so first job would be to take the throttle body off and clean the b'jeseus out of it (taking care not to damage any probes or sensors inside the body) and then removing the TPS, making sure it's clean (use electrical contact cleaner) and moving freely. Also have a look at the wiring to the connector.
Ralf S.

Click to expand...

Well... Truth be told I've covered all the instructions above. The throttle body is mostly clean and I've cleaned it again before posting this topic.

I actually dismantled the throttle body e.t.c....(I have two throttle bodies and none of them seem to work ok so I'm thinking its not a TB issue) I'll post details of what I tried on another response if it becomes necessary.
(I don't want this reply to be too long.)


In any case, these are the fresh steps I took today.

Disconnected the pressure sensor on the AC line, disconnected the compressor.(right now I don't care for the AC. Just need the engine working first)

I patiently cleaned out the throttle body again.

Sprayed the Throttle Position Sensor (didn't really pay attention to the sensor before now) Just assumed the throttle body was all that needed cleaning.
Also couldn't find how to dismantle the TPS so I just sprayed the hell out of it.

Also cleaned the D4 connector under the fuse box behind the battery (the one that feeds the ECU) and also the connectors on the ECU.

Opened the ECU and everything looks pristine so I closed it back.

Painfully tested continuity between the ECU connector and throttle body connector one by one cos I don't know which goes to which. I was able to find matching pins on the ecu to the throttle body so I believe it's not a communication issue.

I did a throttle relearn.

Started the car. P1220 still present.

Cleared the error and tried again. Error still present :-(

I let the car warm up and revved the car till it red lined. Did that 4 to 8 times.

Error gone now.

So I'll drive around normally and post an update if the issue returns.

Thanks

That's good news.

I think the error was still there while the car worked out that it had gone away.

In the old days... even before the Stilo ruled the Earth, errors were stored on a low-capacity chip and were shuffled down a list every time a new error was added or an "all clear" was logged. When the chip was full, the old messages disappeared off the bottom and the system would report "no errors", if the remaining/more recent messages were just normal parameter data.

I guess the newer systems are more sohpisticated and the chips are probably big enough to log moon-mission quantities of data compared to before... but there may still be some old dinosaur programming left over that works in the old way.


Ralf S.

Ok. So after a week of regular driving the issue beginning to re-occur once in a while.

From all indications I think its the TPS that is the culprit.
I'll give it another round of cleaning.
Any other tip is welcome. I really won't want to buy another throttle body. It doesn't make economic sense at the moment

Finally fixed this. On the third purchase of a throttle body (all were used). The third one finally worked.

Moral of the story, its good to listen to your OBD-II scanner.

I'm not sure how the Stilo 1.6 works out its idle.. but if there's a separate idle control valve (it'll be a black plastic module attached to the intake, near the TPS) then that could be gummed up. If there's a connector block to a black plastic on the throttle body and it's not the TPS, then that's probably the idle control valve.

Take it off and have a look inside. It's a recess with a small cylinder in there which drives a potentiometer.. The little wheel cylinder should be able to rotate very smoothly. If yours are jammed/sticky then spray it to clean out the gum etc. It's very delicate so a toothpick is ideal for freeing it up.

Unless yours looks nothing like this... ^ but I hope that helps.


Ralf S.