fault code 16555. please help

G

gg19

Member
hi every1.
i bought a2 which was my desire and now my desire is how i can fix my car... i hav got fault code 16555, which indicates to many possible problems.. after cleaning half of sensors still i am with strange rough idle problem. if i am disconnecting egr valve my car is absolutely fine but here i am connecting egr valve its giving me nice gift of rough idle. and this fault code 16555 is not indicating problem with egr valve, o2 sensors are all changed 15000 miles ago so hope fully they are ok.
if car is running fine without egr valve so what can be possible reasons for this rough idle?
still can be map sensor? or may be ecu fault? any body have any idea about it? please help....
my car is a2 1.4 petrol. thanks
 
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gg19 said:
hi every1.
i bought a2 which was my desire and now my desire is how i can fix my car... i hav got fault code 16555, which indicates to many possible problems.. after cleaning half of sensors still i am with strange rough idle problem. if i am disconnecting egr valve my car is absolutely fine but here i am connecting egr valve its giving me nice gift of rough idle. and this fault code 16555 is not indicating problem with egr valve, o2 sensors are all changed 15000 miles ago so hope fully they are ok.
if car is running fine without egr valve so what can be possible reasons for this rough idle?
still can be map sensor? or may be ecu fault? any body have any idea about it? please help....
my car is a2 1.4 petrol. thanks
Click to expand...

16555/P0171/000369 - Fuel Trim; Bank 1: System Too Lean

Possible Causes

  • Mass Air Flow Sensor (G70) defective
Possible Solutions

Check Mass Air Flow Sensor (G70)
Check Fuel Pressure Regulation
Check Fuel Pump
Check Injectors
Check Intake System for Leaks
Check Exhaust System for Leaks
Check Secondary Air System for Leaks
Check Vacuum Pipes for Leaks





Also have a look through my post here:

http://www.a2oc.net/forum/showthread.php?t=7756&highlight=how+to+fix



Cheers

Sarge
 
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hi not sure if this applies to your engine but my fsi 1.6 had split its egr pipe.it is a corrugated steel pipe that runs from the exhaust manifold to the egr valve at back of the right hand side of the engine.i also know of another fsi that has just had his replaced due to same split. symptoms are irregular idle and eml light on dash.when scanned it also gave lean mixture codes as well. as another symptom with the bonnet off can you hear a slight blowing noise when idling or if you blip the throttle? i hope this is of some help mike
 
many thanks

first thing tomarrow morning i'll check that. its extremely annoying when car is running perfect and idle is playing.. 6 seconds good then floating in water and some times erratic... and already i spent 190 quid.. they changed charcoal canister....... i still dont know how comes?????
and now i am scared to go to any where.. last solution i'll drive without egr valve....., its perfect. if you please guide me with one thing is there any chance of defective map sensor .. asking because car is running perfect without egr valve? map is working when egr is disconnected? thanks a lot.
 
Hi gg19
I'd go with Mikes suggestion of a split egr pipe. When the egr valve opens, air will be drawn in through the spilt causing a weak mixture. This would be particularly noticible at low engine speeds as fuelling levels are so small. Even a small ammount of unmetered air drawn in with the exhaust gas will make the engine run weak

Cheers Spike
 
thanks spike..

spike thanks a lot for reply,
but dont you think if pipe is leak, it should lean with egr disconnected because valve is in the begining and leak pipe should send leakage to manifold. and can it be ecu (electrical problem) asking this because my abs light comes up and when i unplugged egr it disappeared after re ignition? please guide me with this. many thanx. :confused:
 
Hi gg19 the reason is is still lean(or actually thinks it's lean) is if air enters the split in the egr feed pipe and goes into the exhaust manifold this is then detected by the lambda probe-hence lean mixture alarm is raised.as the egr valve is at the inlet manifold end of the pipe it is possible to blank off the egr pipe at the exhaust end.Just be aware that by using the availableblanking plate it should not be used on the egr valve itself as it's actuator projects upwards into the feed pipe itself. This is of coarse my opinion on the fsi engine yours being 1.4petrol may be different.good luck mike
 
Hi gg19
I don't have the petrol engine and can't find any diagrams of the egr system so this is all guesswork for me.
The suspect flexi hose links the exhaust to the inlet manifold via the EGR valve. As the fault goes away when the EGR valve is immobilised this suggests to me that excess air is only drawn into the intake when the valve is working
Mike's suggestion is certainly valid as air drawn into the exhaust system would be measured by the O2 sensor. Perhaps it could be a combination of both, with the engine just managing to correct the continual air bleed into the exhaust, with the final straw being when the EGR valve opens and extra air bleeds into the combustion chambers.

Cheers Spike
 
time to act........

thanks guys,, both of your point is logical. well its not easy to take out this pipe but inspection is must. i'll try to do by myself and will come back with outcome. thanks again for both of your help.
 
gg19 said:
thanks guys,, both of your point is logical. well its not easy to take out this pipe but inspection is must. i'll try to do by myself and will come back with outcome. thanks again for both of your help.
Click to expand...

Have you tried unplugging the wires to the EGR-valve? You will get the engine management light, but the car might run fine. Just spent 350 quid in work money on the fault:

17961 - Barometric / Manifold Pressure Signals: Implausible Correlation
P1553 - 35-10 - - - Intermittent

Turns out to be the EGR valve even though it seems to be working.
Driving with the connecter pulled out now. Seems to do the trick.

Cheers,

-P-
 
hi, basically i bought car with management light on... and fault code was 16555 (system too lean- bank 1) , its indicates 8 or 9 different things. first mechenic who found this code was hesitate to touch car, he started with air leak check but not thoroughly... i felt he is not interested he guided me to go to dealer and dealers are charging 132 pounds for one hour, i know it can be easlily 2 to 3 hours diagnose... anyway i went some where else (VW and AUDI specialist),, but they were crap as well they changed first throttle body and put second hand.. car wasn't fixed then they changed charcoal canister.. symptoms were still there.. then after arguing a lot i gave them back there second hand throttle body.. but they didn't take back canister , as they were saying they orderd new on my instruction and when they were calling me to order they were saying my one is broken so definately this is the problem. but it wasn't... and i spent 190 quid for absolutely nothing.. on top of that they were keep saying that car is fixed and this is normal with audi (rough idle or floating idle)... then i started reading articals almost 2 hours daily and started unpluging things like purge valve, map sensor, o2 sensor, but nothing really came up. i checked car for leaks maybe 10 times but nothing. then one day i unplugged egr valve and car was like brand new.. i was so much happy to see my stable rmp.. then i cleaned egr valve,i put new gaskits.. but after plugging again same symptoms, now i have to check this pipe and for this i have to take it out for propper inspection.. i think pipe is leaking from somewhere,.. if it wont be pipe i'll drive with unplugged egr valve.. i was reading here that its harmless to drive without egr.. at the end i am feeling so much sorry for those people who are not having any idea about cars and they are believing what garage people are saying .......:rolleyes: i am very thankful to all you guys who helped me with this..
 
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Good! The fuel eco can be even better without the EGR. no harm done. Many people plug their EGR-pipe because it pollutes the manifold. I don´t think it is due to a cracked EGR-pipe, as the car runs fine with the EGR-valve closed. The EGR valve can seem to be operating just fine (piston moving up and down, as in my case), however its just messing with your brains. A new valve is about 230 quid here in Norway. You could get a new one for about 100, or if you can live with the management light its free! There will be some additional cost for resetting/programing the new valve at the mechanics as well.

Cheers,

-P-
 
thanks P..

hmm!!! so it means both of us audi's are doing same thing that egr is not working properly but computer is unable to see this, and throwing different codes.., i was reading somewhere that in long run its not good for engine to drive without egr valve.. do you agree with this? anyway i am very happy to drive without egr if its not harmful and whats the good way? just unplug it or block pipe with anything? please guide me with this. thanks.
cheers, gg19.
 
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Attention

hi guys. . i have checked my egr pipe and its fine no leakage.. anybody and idea.. what can be wrong??
 
And the car runs fine when you pull out the connecter for the EGR valve? If it does, its probably the valve it-self. You could get them to try to reset the EGR-valve. In my case they could not manage, again pointing to a faulty EGR-valve. At least thats what my Audi mechanic thinks. He also said there is no harm in driving without the EGR-valve operating.

Cheers,

-P-
 
thanks P..

i've given up.. car is very nice, smooth lovely drive just amber light dosn't look nice,, no egr no problems. so all is ok. thanks for help..
cheers gg19.
 
I had an issue with the following;

16555/P0171/000369 - Fuel Trim; Bank 1: System Too Lean

Addmittedly i have not fully resolved the issue, but I did have a very unstable idle and a little loss of power which I did solve.

As most people on the forums pointed to the MAF I changed this but this did not resolve the issue, just cost a lot of money. Believing I had an air leak I disconnected the air intake pipe from the air filter, rotated it to point up, covered the end and blew into it to presurise it (engine off of course!). Air did seem to be leaking as i could hear a whistle,.... It took me a day, near madness and nearly killing my poor asmatic (and deaf) father to track the air leak down.

At the back of the engine, low down (below the throttle body) where you can't see or reach without jacking the car up and reaching up from below is a rubber pipe which goes from the engine case (via a valve) up to the brake master cylinder. In my case this had split where it plugged into the engine.

Cutting off the split end and reconnecting solved the eratic idle and lack of power. I still have the MIL light on but its a step forward!

Might be worth adding this to the check list for this type of fault....

Regards
 
Thanks, but could you be a bit more specific of where and what part you fixed.

What does it do, and why was it related to your problem. A picture from a manual would be great!

You see, my problem was just partially resolved disconnecting the EGR valve. Recently, however, the problem with sticking revs between gear shifts, rough idle when moving slow is an increasing problem (you mention brake master cylinder).

You see, if I´m typically moving from 50 mph towards a roundabout and slowing down by pressing the clutch in, or leaving the car in neutral, the car idle fine when the car is in fast movement, but as I am approaching the roundabout and about 10 mph (with the clutch in, or gear in neutral) the revs start to bounce from 1000 rpm to about 2000 rpm. It will keep doing so between gear shifts passing trough the city at slow speeds.

funny thing, annoying, and it beats the H out of me !

Cheers!

-P-

the_IT_bloke said:
I had an issue with the following;

16555/P0171/000369 - Fuel Trim; Bank 1: System Too Lean

Addmittedly i have not fully resolved the issue, but I did have a very unstable idle and a little loss of power which I did solve.

As most people on the forums pointed to the MAF I changed this but this did not resolve the issue, just cost a lot of money. Believing I had an air leak I disconnected the air intake pipe from the air filter, rotated it to point up, covered the end and blew into it to presurise it (engine off of course!). Air did seem to be leaking as i could hear a whistle,.... It took me a day, near madness and nearly killing my poor asmatic (and deaf) father to track the air leak down.

At the back of the engine, low down (below the throttle body) where you can't see or reach without jacking the car up and reaching up from below is a rubber pipe which goes from the engine case (via a valve) up to the brake master cylinder. In my case this had split where it plugged into the engine.

Cutting off the split end and reconnecting solved the eratic idle and lack of power. I still have the MIL light on but its a step forward!

Might be worth adding this to the check list for this type of fault....

Regards
Click to expand...
 
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