Idle Control Valve S4
1. If I start it with the Idle Control Valve connected, the car runs for a few seconds than dies, Check Engine light on - error 1222 - "Idle Speed Actuator or circuit".
2. If I unplug the ICV the car starts and idles at around 1000-1100 RPM. Check Engine light comes on since the ICV is disconnected.
Once the car is started with the ICV disconnected, I can plug the ICV back in, and the car continues to idle at 1000-1100 RPM - the Check Engine light goes out but I'm guessing the ICV is bypassed.
3. If I start the car with the ICV plugged in and keep the RPM up so it doesn't die, after a few minutes it will idle at 1000-1100 RPM and I can restart it without it dying. The idle hunts a bit.
I changed the ICV with a new BOSCH OEM, changed the rubber grommet with a new one, same thing. Also tried a new TPS, same thing.
Can anyone shed some light on this?
Before it started doing this, there was some hunting at idle, and some stumbling at idle when the fan kicked in, heater was on.
At that point I cleaned the ICV, throttle body, Oil Separator, VVT, and changed the plugs from Golden Lodge to NGK BP7's. The car felt much more responsive etc, but it started dying at idle.
Well, that’s a dilly of a pickle.
I assume your TPS is adjusted correctly? If so, my first guess would be a really sneaky vaccum leak somewhere.
Didn't mess with the TPS when it first started doing this. I did mess with it later.
I adjusted it manually - so it clicks just off idle.
And with the multimeter.
Didn't make a difference.
You're saying there might be a small leak which idling with the ICV wouldn't be able to overcome, but idling without it would?
But why would that get flagged as a 1222 error?
I don't have a full grasp of all of the variables in the system yet.
One thing - probably unconnected, but, what's responsible for the start up chime sound?
Reason I'm asking is because it's very erratic, most of the time it doesn't chime.
Air leaks can cause all sorts of weird problems and the computer isn't very sophisticated, so it's possible that could get flagged as the wrong thing. Is that your problem? Mongo dunno, but air leaks can be pretty insidious.
You mean the seat belt warning or the key/door chime? The door chime with the door open and the key in is triggered by one of the switches at the front of the driver's door, and it's not uncommon for that switch to need a bit of cleaning. Seat belt I can't help you with as mine was apparently disconnected long ago.
Yeah, key/door one.
Re: leak - so, with the ICV connected the idle would be lower than 1000-1100,
the leak causes the idle to drop, and the engine stalls.
with the ICV unconnected the idle is higher so the engine doesn't stall.
Is that what you're saying?
if code 1222 is ICV or "circuit" and the ICV is new, try checking the circuit...
pin#1 of ICV goes to pin #87 of motronic red stripe relay plug, an orange wire (as the motronic relay has TWO pin# 87s, it is the pin #87 with the thick red and the orange wire, not the pin #87 with the TWO reds....just for info!)
pin#2 of ICV goes to pin #33 of ECU plug (a blue/black wire)
do you at least have continuity in those two wires?
I noticed from your other thread, that the one thing messed with by a PO on your car was the AFM
Can you borrow a good, unmolested AFM to test?
I can post here the various resistance/volt tests you can do on the AFM, if you want to see if yours comes within parameters?
cannot comment on the chime, that will be a USA S4 thing (seatbelt chimer likely?)
Alright, I'll check this. That's why I was asking about the chime - was thinking an ECU issue.
I checked the voltage at the ICV connector - 13.85v
Resistance was 8 ohms as I recall.
Not really, but I'm still unclear if on the S4 that screw does anything - I've read comments that it doesn't. I turned it several turns and no change.
Btw - what's the connection between the ICV and the VVT?
Saw some comments that the ICV is needed for the VVT.
Check inside the plastic connector blocks for a displaced connector. There is a small tab on the metal parts that is supposed to lock them in place. But sometimes they get pushed out of position inside the plastic connector - then the metal parts do not make a secure connection even though the plastic part is plugged in.
My understanding is that on Motronic with lambda sensor that screw on the AFM doesn't do anything. I recall reading this in one of the Bosch books somewhere.
Generally it's a bad idea to touch your voltmeter to anything that goes to the ECU (i.e., the harness connector) so don't do that, BTW.
these are values from a test on my S4 AFM.
pin#4 is ground.
Note: Terminals/Pins are numbered 1 to 5 from RIGHT to LEFT
Resistance test (remove plug and test between AFM pins...NOT plug pins!!)
2+4: 62 Ohm (Reference value about 100) - OK (note: on another AFM that works perfectly on my car, I got a reading of about 40)
5+2: 2400 Ohms (ambient temp, ca. 20C) -OK
3+4: 352 Ohms (Reference value about 400) – OK
these though are the more important tests, the Volt tests:
Plug reconnected, the connector’s rubber boot needs to be pulled back to backprobe the wires; DVM set to 20VDC and connected; only then, turn Ignition ON:
1+4 (CO pot output): 2.48V (Value 2.5V) - OK
3+4 (Reference voltage from ECU): 4.97V (Value 5.0V) - OK
Flap Movement (top half airfilter removed for access) rubber boot pulled back and back probing the Plug, then open/close the flap with your fingers:
2+4 (Airflow output): closed flap 0.25V >>> 4.50V with flap fully open. – OK
Nb: Voltage should rise and fall absolutely smoothly as flap is opened and closed, otherwise the track needs cleaning (ONLY clean with isopropyl alcohol – NOT contact spray!) If cleaning does not help then the arm will require bending to sweep a new part of the track)
ICV connector's ok.
I'll check the MAF values.
I just started it with the ICV disconnected and plugged it back in immediately and it stalled within 2 seconds.
Maybe I bought bad ICV.
In any case, with the ICV detected the ECU would run a different program
The idle would be lower than 1100 RPM so a leak would affect it more, fuel pressure regulator? (saw some threads about that).
But it seems strange that it would get flagged as a 1222 / ICV error.
Can you bench test the ICV with a 12v battery and test wires? This may help to settle if you have one, or two good-bad ICVs. Also, can't hurt to check-clean all ground connections for the engine and ECU system. Also, the best way to check for vacuum leaks is with a smoke machine. Any good independent German shop should have one.
Just ran it again:
started up ICV unconnected - dead smooth idle at about 1100 RPM
connected ICV after about 1 minute - idle started hunting between 900-1100 RPM
Turned it off.
Restarted with the ICV still connected - it won't stall if I had already ran a bit without the ICV.
Idle at around 850 RPM. Gave it a little gas, RPM's dropped to about 1100 and started hunting between about 900-1100 again.
The RPM's drop slowly after about 1500 RPM.
And shutting it off with the ICV connected there's a bit of an engine run-on.
With the ICV disconnected it shuts off instantly.
So basically it's not running right with the ICV connected.
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