[Supahone]

My 08 328xi N51threw these codes related to the secondary air pump. PA200 P0492 The relay and the two fuses all checked and tested fine. The power line to the pump checked out on start up. The air pump was bench tested and it runs fine. The valve was a bit dirty and I cleaned it out and air does pass through and it seals on the opposite flow.The manifold from what I can see was not clogged. But I gave it a once over. I put everything back together and got pending code again. Have the check valve on order and plastic hoses but what else could could throw this code?

[Serf27]

Did you clear the codes?
Pending codes are those that sensed a fault previously and are waiting to see if the fault will come back.

[Supahone]

Yes, I did clear it. It stayed off for about 20 miles until all the monitors were ready. By the way Evap did not clear even though I have a new gas cap and half a tank of fuel. Parked the car for about 4hrs, started the car and I got the pending code. Cleared it again and will wait in the morning to do a real cold start. Typically it would throw a code a few minutes after the first cold start of the day.

[mjson31]

Have you been able to find a solution to your problem? I'm in the same boat and have not been able to find a solution...

Pump works fine
Valve works fine
Hoses have no cracks or leaks
I've even changed the two pre-cat o2 sensors

I don't know what to do next or how to go about it

[Supahone]

I actually ended up selling the car before figuring out what was wrong. From what I understand it could have also been a faulty upper o2 sensor as they get fouled from being caked by exhaust oil. Hope you have better results then I did.

[Supahone]

I also heard it could be a coding issue. Where the ecu needs to be reflashed or modified.

[mjson31]

Thanks for the follow up. I've replaced the O2 sensors, that unfortunately didn't solve the issue.

Flashing the ECU seems interesting but I think that may bypass the issue rather than to solve it. I'm currently exploring the use of Techron or some other cleaner additive to clear out the bank2 ports.
I've noticed on three e90s not suffering from this issue, the O2 sensor currents are roughly in line with one another: O2s1b1/O2s1b2 (read that as: o2Sensor1Bank1Current divided by o2Sensor1Bank2) being ~0.9-1.1 throughout the secondary air pump's cycle.
On mine, that ratio fluctuates anywhere from 4-10.

I'll post if I find a solution (to help the next guy out)

[tercero]

Originally Posted by mjson31

Thanks for the follow up. I've replaced the O2 sensors, that unfortunately didn't solve the issue.

Flashing the ECU seems interesting but I think that may bypass the issue rather than to solve it. I'm currently exploring the use of Techron or some other cleaner additive to clear out the bank2 ports.
I've noticed on three e90s not suffering from this issue, the O2 sensor currents are roughly in line with one another: O2s1b1/O2s1b2 (read that as: o2Sensor1Bank1Current divided by o2Sensor1Bank2) being ~0.9-1.1 throughout the secondary air pump's cycle.
On mine, that ratio fluctuates anywhere from 4-10.

I'll post if I find a solution (to help the next guy out)

Did you fix the issue? my car has the same problem and I can’t get it to pass smog.

Let me know.