Smog monitors not setting (Air, O2, Cat)

[BimmermanJp]

Hey guys i fixed a leak in the secondary air system - monitor wasnt setting so i decided to see what was wrong. The check valve off the air pump is working - smoked the lines after that and found 1 leak - fixed it and cleared the monitors to see if it would set and now i have 3 monitors that arnt setting - secondary air, Oxygen sensor (not heating), and Cat monitor. i've driven like 300 miles already and nothing. wondering if any has any ideas. If its helpful - before the repair all the monitors were set but the secondary air. Possible that secondary air issue could cause other monitors not to set?

[dworthy]

Well there is a drive cycle you need to do. It can be tough depending on where you live as you have to keep and maintain a certain speed. See the attached.

[flyfishvt]

Well there is a drive cycle you need to do. It can be tough depending on where you live as you have to keep and maintain a certain speed. See the attached.

As long as you don't exceed 60mph or 3000rpm the drive cycle will pickup where it left off once you get back up to speed. Example....one part of the drive cycle is to drive 20-30mph for 3 min 15 seconds. If you drive for 1 minute and hit a stop sign the drive cycle will pause at the stop sign. It will pick up at the one minute mark as soon as you get back up to 20 mph.

http://www.instructables.com/id/How-...or-Smog-Check/

[BimmermanJp]

I've seen the drive cycle and have followed it to a T... but for some reason it still isnt setting. I'll try again in the next night or 2 to try it again, but if the O2 sensors are slow responding could that be the cause of the o2 and cat not setting?

[dworthy]

How old are they? BMW recommends replacing the oxygen sensors every 120k miles, so if you are past that, then I would lean towards yes.

[BimmermanJp]

Yeah im at 128k - so i guess ill replace those and reset the monitors. Hope that'll take care of the O2 and Cat, but this air monitor haunts me... Wanted to ask theres a vacuum control valve below the back of the intake manifold that when i smoke test - seems to leak out of it, but on the back of the valve itself it has a cap that looks like its suppose to release pressure. it does have 2 lines going into it part # 11747810831

[dworthy]

I would get the tank vent smoke tested to ensure the integrity of it. From the P/N is a rubber hose going to a valve, if it is original, replace it.

Next, use Bosch oxygen sensors, at they fit perfect, and are about half the price you would pay at a dealership. Use this website to get the Bosch part numbers and look them up on Amazon to start with.

http://www.boschautoparts.com/Vehicl...artFinder.aspx

[BimmermanJp]

tank vent? the fuel tank vent valve? or the vapor canister filter? and this is part of the secondary air system?
ya i might as well replace those lines and that 1 way valve you're talking about
i can get bosch o2 sensors through my work so no problem there.

[dworthy]

That valve is used to open the valve on the exhaust manifold for the pump can push fresh air into the manifolds during cold start. Normally it is only open for 30-90 seconds.

Yes I am talking about the vent system if that is also not setting. There is a canister and lines back to the fuel tank.

[BimmermanJp]

Oh ok the check valve off the secondary air pump. i get ya. i vacuum tested it and it held vacuum.

The evap system has set.

[dworthy]

Cool, you are on the right track.

Lastly are there any codes associated to the secondary air system?

[BimmermanJp]

yeah so im surprised as to why the monitor hasnt set - pump works, check valve holds vacuum - fixed an air leak. seems like it should be setting now

so theres no pending/current codes - i found a history code using Autologic
246 - secondary air system bank 2
245 - secondary air system bank 1
i believe for insufficient output

[dworthy]

Okay, that means if these are still in since the last time you cleared the codes, there is still a problem.

You can try to clean the codes, go for a drive cycle if the stuff was fixed since they were last cleared.

[BimmermanJp]

Right - just trying to figure out the problem. I've been reading that if the O2 sensor are borderline not working that it wont meet the pre requisite for the secondary air monitor to run its test.

" ENABLING CONDITIONS:
1. Coolant temperature sensor = -10C to 70C (the intake air temperature is not an enabling condition)
2. Barometric sensor in the control module was basically an altitude sensor of pressure of a realistic maximum of 8,000 feet (6,000 under some conditions).
3. Air flow was complex as a function of engine speed (basically not below 640RPM)
4. MAF measured in milligrams per stroke - but basically the MAF has a wide range
5. Oxygen sensors heated and active

Once the enabling conditions are met, then the test conditions can be run"

http://www.bimmerfest.com/forums/showthread.php?t=926921


I did also have a bank 2 sensor 1 O2 code - not pending or current

[jclausen]

Clear all faults then drive after each drive check again for faults if faults return the monitor setting process will stop.

[flyfishvt]

Doing a proper drive cycle should set all but 1 or 2 of the monitors. That should be all that's required to pass an emissions scan. Federal law allows up to 2 monitors not set to ready. A few places have instituted rules that only allow 1 monitor to be not set. If you get it down to 2 monitors then those will set themselves by just driving the car for a few days.

[BimmermanJp]

Thats what i plan, but i live in the great state of California where only the Evap monitor is allowed not to set. haha

[BimmermanJp]

i'm gonna check the voltage of the O2 sensors during and after the secondary air pump has ran - figure out if they are working properly.

[jclausen]

In california only one does not have to be set, evap

[flyfishvt]

i'm gonna check the voltage of the O2 sensors during and after the secondary air pump has ran - figure out if they are working properly.

Checking o2 sensors is easy. Hook up an OBD2 scanner and look at the live data. The voltage on the sensors should be constantly switching from around 0 to around 5 volts. The secondary air pump has nothing to do with it. The secondary air pump runs for about 1 minute on cold start to help the cats heat up quicker.

[Jackson42]

I fixed a buddy's 330i with similar symptoms by replacing the primary side O2 sensors - one of them was dead as a hammer. It cleared the secondary air code within about 30 seconds of the startup following the replacement. And yes, that was here in SoCal.

[jclausen]

Secondary air introduces ambient air in to the exhaust manifold to dilute the rich mixture on cold start up. Secondary air has no sensors on it because the oxygen sensors are looking at the cold start rich mixture, if the pump is not working for instance the fault low flow would probable come up. But it is monitored thru the oxygen sensors

[BimmermanJp]

The secondary air pump does have something to do with the O2 sensors becuase the O2 sensors monitor the extra air that goes into the cats during startup.
Yeah i'll be replacing the Front O2 sensors today and see what improvement that brings.
The Pump is working, check valve holds vacuum - leak fixed.