Code P1124, P1126, P0446

[bar10dah]

LOL, thanks Logray. You're probably right. I've been beating myself up over this problem for five months. It's hard to just stop worrying about it. I'll just drive it for a while and stop hooking the Durametric up to it every other day. :)

[sak_27]

I also replaced my vent line, almost 600 miles ago, and my CEL problems have disappeared. My fuel trim numbers looks like this:

Can anyone help me interpret these readings?

Thanks

[sak_27]

For some reason, couldn't put my screen shot on, but here are the fuel trim numbers:

Range 2 Cylinder 1-3 (FRA) 0.94

Range 2 Cylinder 4-6 (FRA2) 0.94

Range 1 Cylinder 1-3 (TRA) -0.02

Range 1 Cylinder 4-6 (TRA2) -0.02

[bar10dah]

Range 1, idle state, looks pretty good. Range 2 numbers are fairly good too. Range two, at speed, is slightly rich, so the DME is compensating by leaning the mixture. But only slightly. In fact, I can't find the chart now, but your Range 2 may be well within tolerances. Ideally, Range 1 should be 0.0 and Range 2 should be 1.0.

[bar10dah]

Still getting the higher Range 1 & 2 readings.

For the first few months, P1124 and P1126 wouldn't come back for a long time. But now, the codes come back sooner and sooner. They seem to be associated with prolonged idling. The more I idle, the quicker they come back. Usually, I only get P1126. Occasionally both. Wondering where I should look next?

[evetselous]

RE Post #67 ... How did you remove and replace the valve and vent line at the intake manifold? It looks inaccessible to me. Did you remove the intake manifold? Did you have to get under the car to route the line forward to the EVAP system?

Steve

[bar10dah]

I didn't. I just ran the new line next to the old. The bolt that holds the line to the intake manifold is too difficult to get to, so I just left the old line in place and will install it properly the next time I do a throttle body cleaning.

[evetselous]

Thanks. I get the same codes (see my post on the wiring to the Shut Off Valve 996.605.201.01) which it though was a problem with the shut off valve not, well, shutting off. I blew through the line to the vent line and valve at the intake manifold and thought it was OK because I could get air through it. I did not know it was supposed to be closed and holding a vacuum when the engine was off, which is what I read your posts to be saying. I guess I should check out that valve too.

Same question as above, though. Did you have to get under the car to connect the forward end of the vent line? I cannot see where is attaches on my car.

[bar10dah]

Closed and holding a vacuum at the charcoal cannister is just a guess. From reading the Bentley manual, it appears that valve opens up at certain times to purge the fumes from the cannister, so it appears that it's normally closed. And, I think this takes place when the car is running. I'm not sure what it does when the car is off.

Yes, get under the car. When you jack up the driver's side rear wheel, you can see the three tubes that run down the engine/cabin firewall. I think it was the center tube. It is easier to get to if you remove the wheel and the wheel well liner/air dam that's in front of that rear tire.

[TheLALienTimes]

Hopefully I can be of some help here as I just recently successfully cleared obd codes p1124 p1126 and p0506 from my automatic 99 porsche boxster with about 89k miles on it. I was originally trying to fix the problem myself. I started by replacing all of the o2 sensors and the air filter which did absolutely nothing. The car kept rough idling and doing what I called "ghost revs" where it would just rev up and down on its own even when the car was at a complete stop. I could not find anything wrong with the MAF sensor which seems to be the main cause of this problem, and all of my hoses connected to the air flow seemed to be completely intact.

I gave up after working on it for a couple weeks, as I got this car less than a month ago. I took it to my local porsche mechanic and they replaced all the spark plugs and tubes, outer and inner tube seals, orings and oil tubes as well as the vacuum reservoir which cost me 585 dollars including labor and tax. p.s. ( also had air leak coming from a cracked oil fill tube which I didn't see due to the tight space in the engine bay, and my aftermarket glass window top also makes it even more difficult to get in there)

With those fixes, the codes p1124 and p1126 disappeared. But, after a few days of driving the car started doing the "ghost revs" again and a new code popped up p0506 "idle air control system RPM lower than expected." I took the car back to the shop and had them look at it. Took them all of 45 minutes to see it was the idle air control valve that was all gunked up with carbon build up and dirt and the little door that opens and closes on it wasn't operating properly. He cleaned it up for me while I was there, no charge, and now my porsche is running as smooth as ever. I ran my reader on it and no new codes have popped up.

Hope this helps,

Jason

[Jeremy Cottrell]

Any resolution on this? It's kinda like reading a book only to find the last page torn out.