Code 34 check engine light

[BambamXB12r]

Hey everyone, I have been gone for a while but the bike has been running great until now. I have a 2009 XB12r with 17,000 miles. Race ECM, Drummer SS, and carbon open air box. The other day I was on my way home and the check engine light came on. A few lights from the house the bike started to idle abnormally high. When I got home I pulled the code and it was number 34 for idle air control. There is one code that said IAC position too low and another also code 34 that said IAC circuit failure. I pulled the IAC out and cleaned it up hoping it would help but no luck. I ended up purchasing a new one from St Paul and got it installed. After clearing the code I took it for a test ride and it ran fine but the check engine light came on again. The second test ride did not go so well. After about 15 min the bike started to idle high again. It is running better than before but still not properly. When I got home I pulled the check engine light again and got the same two codes. From here I'm not quite sure what to do. If I missed any useful info please let me know and I will add it. I did some research on here, bad weather, and Google in general but I couldn't find anything. I also have a service manual, do all the work on my bike, and am mechanically inclined. Any help or recommendations would be appreciated.

 

[BambamXB12r]

Bump... anyone?

 

[user_deleted]

mike: when i replace/service the IAC unit i typically clean out the pintel port extremely well with q-tips and carb or brake cleaner. did you?
i also do a tps reset with the throttle procedure at the same time.....then ride in "learn mode" for a few miles after clearing code #34.
if you're still receiving fault code #34 you either have a pinch or chafe in the tiny wiring harness for the IAC unit...or a faulty unit.
can't think of anything else it would be BUT in conjunction with that i would check your ecm ground...dog-bone ground...negative cable-to-frame ground as well. a fault in 1 or more of them will throw random codes and make various sensors flare up and throw random fault codes as well.

PS-i realize it's after the fact but you should have contacted me for the IAC. i have them NIB for less than 1/2 the st. paul price. damn shame.

 

[BambamXB12r]

I did do a tps reset and clean out the pintle port really well when I did the replacement of the IAC. I went through all the grounds when I pulled the bike apart again and found the culprit. There is a plug on the side of the throttle body that was cracked and letting a ton of air in. I believe the port is for the evap can on CA models but I could be mistaken. After replacing the plug and going through all the grounds she is running perfectly. Thanks for the heads up on the parts for the future John. I’ll reach out to see if you have anything available next time. I have put 1000 miles on it since the last post and no problems at all. Thanks again for your help.

 

[njloco]

I don't see any beer in this picture ?

 

[Cooter]

That pic makes me damn jealous BamBam.:sorrow:

 

[cptCrash]

I've been struggling with the same problem on a 2009 XB12XT with 36000m on the clock. I only get the symptoms and the exact same DTCs when hot, bike runs fine when cold.

First had intake seals replaced, what changed the characteristics of the problem, but failed to eliminate it. Then came the new IAC - no improvement at all. Already done quite a few TPS resets, but i don't think they made any difference in my case. At this point i'm messing with logs recorded using ECMdroid, and all i've managed to find so far is that the TPS value is slightly higher when the symptoms are present - 4.2 on idle normally, fluctuating between 4.5-4.7 when rough.

Tomorrow i'm gonna go find that plug..

 

[Barrett]

located at prominent position on throttle body housing. see pics for open and plugged. i've never seen one that was NOT pre-drilled and capped from the factory...that was not destined for calif or euro-spec.
i was formerly "user_deleted" before i was badgered and beaten into submission....then banned. check info above and closely check your grounds, specifically the dedicated ECM ground. radically affects how all these sensors perform and the storage of historical fault codes.

 

[cptCrash]

Hi Barrett, thanks for the pictures. I'll see what i find there, as my bike is Euro-spec.

Yes, i saw your previous comment. I have already though of a wiring fault, but everything was intact all around the engine and the dog-bone looks like new as well.
Where is the ECM ground on these exactly? isn't it just one of the pins on the ECM connector?

 

[Barrett]

Hi Barrett, thanks for the pictures. I'll see what i find there, as my bike is Euro-spec.

Yes, i saw your previous comment. I have already though of a wiring fault, but everything was intact all around the engine and the dog-bone looks like new as well.
Where is the ECM ground on these exactly? isn't it just one of the pins on the ECM connector?

yes sir, my pleasure.
your ECM should have 2 distinct ports with a harness plug attached to each. each port has pins numbered 1 thru 11.
pin #11 on one of the ports should have a single black wire going to ground source. a few of the ECM's have single black wire on pin #11 of both ports going to ground. i can't recall which years have both...check yours.
also note that a dedicated single ground wire from the rear coil mount cap head bolt to the rear frame rail ground mount screw, often times improves rideability...starting motor speed....improves charging system output consistency...and lessens the chance of abnormal sensor fault codes being stored.
here's standard ECM schematic for XB

 

[34nineteen]

i was formerly "user_deleted" before i was badgered and beaten into submission....then banned.

 

[cptCrash]

Well, had a look. Infamous plug is in place (on Euro-spec) and fully intact. ECM ground pin, connector, wire all good. No marks on the harness. Only thing i've found was the breather pipe on the rear cylinder being loose. :grumpy: weiird..