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Discussion Starter · #1 ·
Just had the check engine light come on in my 02 325 XI and had it plugged in at autozone . 2 codes came up .
1.) P0492 secondary air injection system (bank 2)
2.) P0491 secondary air injection system (bank 1 )
The code reader recommended that the likely solution is the replace the smog pump. Now this is a 300$ part that I would rather not replace but will if I have to . My question for you guys is taking into consideration that I have never replaced the upper or lower intake boot , or DISA gasket , and the outdoor temp sensor is no longer with us thanks to the previous owners, could this be a vaccume leak? . I know all these things I'm listing are all connected to each other eaither physically or electronically . I do hear a new hissing sound around the top back drivers side of the engine closest to the cab , and
The car does start a little rough in the morning but immediately smoothes right out .

Any and all input would be appreciated .
 

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First order of business, NO PARTS, yet! FORGET about what the Parts Store counter jockeys or the Parts Store Scan tool told you. This is likely WRONG info until you do your research.

2nd order of business, buy the OBDFusion App for your phone or tablet and get the proper VeePeak OBDII interface from Amazon. Android requires Bluetooth, iProducts requires Wifi. You are looking as less that $30 for the App and interface.

3rd order read and search, here is some light reading for you:

Start this this thread for an overview - http://forum.e46fanatics.com/showthread.php?t=897616

Then PLENTY of SAP info, NOTE that the Pre-cat O2 sensor can and are often a contributing factor as well.

http://forum.e46fanatics.com/showthread.php?t=1041726

http://forum.e46fanatics.com/showthread.php?t=1023149

http://forum.e46fanatics.com/showthread.php?t=965526

http://forum.e46fanatics.com/showthread.php?t=1052605

http://forum.e46fanatics.com/showthread.php?t=1074847

http://forum.e46fanatics.com/showthread.php?t=1074573

http://forum.e46fanatics.com/showthread.php?t=106959

http://forum.e46fanatics.com/showthread.php?t=1074847

http://forum.e46fanatics.com/showthread.php?t=106959

http://forum.e46fanatics.com/showthread.php?t=1078986

http://forum.e46fanatics.com/showthread.php?t=1096889

http://forum.e46fanatics.com/showthread.php?t=1100895

https://www.youtube.com/watch?v=AsgB9eBl58I

https://youtu.be/1sRZ5ves1DM

Cheap fluid transfer pump from your local auto parts store or Amazon.

http://www.amazon.com/ABN-Multi-Use...=1-1-spons&keywords=fluid+transfer+pump&psc=1

A few rubber gloves, rubber bands and some cheap mini cigars from our local gas station or convenience store.

Also get a good, bright LED flashlight to locate the escaping smoke. Look deep in the engine compartment and under the engine if needed. Do not forget the dipstick guide tube and the lower CCV oil return line. These areas may be hard to see from above in the engine compartment.

After looking for intake air leaks, remove the oil fill cap and allow the crankcase to fully fill up with smoke, then replace the oil fill cap. Check for cracks in the valve covers and leaks around the grommets, half moons and around the perimeter of the valve cover.
 

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Discussion Starter · #3 ·
Awesome this is a great post ! I did a little more poking around under the hood a determined that the hissing noise I am hearing is coming from the DISA valve. Would this throw the P0492 &P0491 codes ?

I figured since that gasket and the upper and lower intake boots are all original with 160,000 miles I should start their .
 

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Awesome this is a great post ! I did a little more poking around under the hood a determined that the hissing noise I am hearing is coming from the DISA valve. Would this throw the P0492 &P0491 codes ?
Not likely, also be very careful, these engines all sound like they have vacuum leaks, you usually cannot hear the vacuum leaks on these engines. What you are hearing is the idle air bypass noise which is normal, but unless you know what a "normal" engine sounds like, it is hard to be 100% sure.

Also look at my comments here for ideas - http://forum.e46fanatics.com/showpost.php?p=17091432&postcount=28
 

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Discussion Starter · #5 ·
Ok. Also how does the SAP air pump know when to turn on ? Does it use a thermostat on the motor somewhere or the outside temp sensor that's mounted up underneath the bumper on the drivers side . I know it turns on when it's 40 degrees or below correct ?
 

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As far as I understand the SAP used the Engine Coolant Temperature to trigger the SAP.

Under most circumstances the SAP will typically run for approximately 90 seconds or until the engines reaches 40C/104F. But there are a few other small exceptions to the SAP behavior that are not so important at this point.

Best to get the OBDFusion App and interface for under $30, you will be able to CLEARLY see if and when the DME commands the SAP to run and you will be able to determine if the Pre-cat O2 sensors are seeing the SAP run as well as determine if the Pre-cat O2 sensors are lazy.

VeePeak OBDII interface from Amazon is the cheapest reliable interface I have seen. Android requires Bluetooth, iProducts requires Wifi. There are other options, but they are more expensive, some closer to $90.
 

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Discussion Starter · #7 · (Edited)
I Bought the veepeak OBDII plug in and app you suggested. Can you give a step by step on what I need to do. Also, this morning was pretty cold and when I first started the car and popped the hood I could hear the pump working. I did not take the hose off to check if air was coming out however.
 

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Suggest you read the PDF in this thread.

PDF - http://forum.e46fanatics.com/showthread.php?t=1097893

Please add the Command Secondary Air Status PID as well, this will hopefully be added/updated soon.

You really need to search YouTube and online for info about the App as well as spend about 20 minutes playing around and getting familiar with it. Overall it is pretty intuitive, however, the HIDDEN menus on any App need to be found. Sometimes there is a Menu icon, sometimes it is touch and hold on a screen to pop up a menu.

The most common problem with the SAP system is the large output hose is cracked and leaking, if the system has a vacuum controlled Kombi/Combi valve, the vacuum hoses deteriorate and leak and most of these cars have original Pre-cat O2 sensors that are lazy. Replace the Pre-cat O2 sensors with Bosch Direct Fit sensors, they are typically around $44 each on Amazon which is one of the better prices I have seen.
 

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The good news is that if you hear the pump running, it is very unlikely that you need a new pump.

On your model, is there a vacuum assist to open the check valve at the exhaust manifold, or does it just push open from air pump pressure? Make sure the vacuum hose (if any) is intact and delivering a vacuum signal on cold start. Remove the valve from the exhaust manifold (two 10mm nuts) and see if it will open. Those valves usually fail open rather than closed, but I can easily imagine one corroding in the closed position.

There used to be a shop that advertised on eBay that would rebuild air pumps. They did one Volvo pump and one BMW pump for me. I did not find them last time I looked though.
 

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Check your hoses to and from the sap. The large one going to the valve corrodes internally and can plug up the valve. If the hose is squishy, order a new one...check the old one for a hole. Same thing with the small vac line aft of the valve...it often cracks.
 

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I checked the vac line that runs from that valve to along the valve cover to the back of the engine and it appeared to be in tact . I am going to perform the bav auto test to check the valve out.
http://www.bavauto.com/newsletter/2008_n408_newsletter.pdf#page=6

Hopefully if it is faulty it's stuck in the open position so it doest fry the pump motor.
The Kombi/Combi valve will not be stuck open because you would not have the SAP codes and the large output hose from the SAP would be melting.
 

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Discussion Starter · #13 ·
UPDATE: Was a little bit warmer out yesterday and the Check Engine light turned off. What could this mean?. It was on for 3 solid days before. I Should be getting the Veepeak reader today.
 

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SES/CEL/MIL can and will turn itself off after a period of time if an error is not detected.

Without an OBDII tool you are totally in the dark.

They should hand out OBDII interfaces when you get your drivers license.

The majority of people drive or own at least one or more vehicle that is less than 20 years old and supports OBDII.

Anyway, once you get your interface, you can then see what is going on and gather data.
 

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Discussion Starter · #15 ·
Update : pulled DISA valve and the o ring was in rough shape , flap and pin were good but it will not hold a vacume seal . I rotate the flap and put my finger over the hole and it very slowly returns without me moving my finger off. Intake boot also cracked.
 

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CCV and Pre-cat O2 sensors are possibly in bad shape/need of replacement as well.

14 year old car needs lots of love at this point.

Fuel pump, filter, relay, spark plugs, valve cover gasket, OFHG, cooling system ......
 
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