05. 645 secondary air injection

I'm getting fault code P0491. Desperate need of suggestions. Anyone else have this problem? And how do I fix it and clear the code?

 

Your car has a V8 engine. The left (driver's side) secondary air system appears to be inoperable or not up to spec. This is an emissions issue so the SES light won't go out until it's fixed. The fuse listing for the car should have a fuse or 2 fuses for the secondary air system. One of those fuses may have blown.

 

Thanks I will try the fuse but it seems like the problem is more serious than a fuse but I probably will put new ones for good measure.

 

http://www.bimmerfest.com/forums/showthread.php?t=881673&highlight=p0491
http://www.bimmerfest.com/forums/showthread.php?t=880024&highlight=p0491
http://www.bimmerfest.com/forums/showthread.php?t=849386&highlight=p0491
http://www.bimmerfest.com/forums/showthread.php?t=711160&highlight=p0491

Read that last link about the blocked head passages and valve stem seals.

Tim

 

getting fault code P0491.
desperate need of suggestions. and when idle for a second and I start move moving from parked position smoke comes out of my tailpipe then leaves after I drive for a second.
I saw a kit on allgermanauto that cleans the air injection of carbon and clears the way.
I'm in the Dallas texas area. Waxahachie tx to be precise. if any one has experienced this problem I would like to know how you fixed this issue.

thanx

It sounds like you have more problems than the Secondary Air problem. If the passages in your heads for the SES are partially or fully plugged, your SE air pump can not mix air on a cold startup. The system only runs when the engine is cold for around 45 seconds or less. After this time period it is not used until the next cold start. Problems with your code could be from a loose or cracked y-pipe that can be seen from the front of the intake. If you jump the SE air pump, you can check to see if there is a cracked or loose pipe to bank 1. The pump will sound like a vacuum cleaner when running. The pump is located in front of the passenger wheel. The pump can be jumped with 12 volts at the pump, or at the relay in the main fuse panel under the cabin air filter. Once the pump is running, listen & feel for air coming out from under the front of the intake. You can also feel or listen for air coming out of the bank1 & bank 2 exhaust
pipes. If you feel or hear any air, that is a good sign.

Your smoking problem is coming from your valve seals, & this has become a very common problem. You can search for valve seals & find several DIY's to read.

Hope this might help?

http://bmwfans.info/parts-catalog/E63/USA/645Ci-N62/may2005/browse/engine/pollutant_reduction_pipes/

 

I saw a kit on AGA that cleans the carbon from the secondary air passages I was thinking about getting and replacing my check valves with new ones hopefully that can clear things up with that problem.

As for the valve seals, do you think I can do this myself? I'm pretty good at taking things apart and putting them back together, I just never worked on a car to that extent. I really wanna save money on this so a good diy would be helpful. I know that people want to charge an arm and a leg to replace them. Thanks for your advice.

 

Be very careful trying to clean the air ports in the heads. Using brake cleaner or other solvents can damage the piston walls. Carbon coming loose from the clogged heads can damage the cylinder walls. There have been very few check valve failures on the Secondary Air system. Since you only have one clogged head, the y-pipe is most likely your 1st suspect. Running the pump will help verify your code.

The valve seal failure is reported as a 40 hour repair, that is very time consuming & technical. You can most likely find a used seal replacement tool, & do the job if you feel comfortable doing it. There are several DIY on the 5, 6, & 7 series forums.

http://www.bimmerfest.com/forums/showthread.php?t=719866

 

I just went and got a new y pipe and new air check valves. I think the check valves are close to the rear of the motor and Ive heard the pump is in front of the passenger wheel somewhere. Is it hard to reach or do I have to take something apart to get to the pump. The times I looked I did t know where I was looking. But the y and the valves are something I can definitely do my self you think??? How complicated of a job it that?

 

I just went and got a new y pipe and new air check valves. I think the check valves are close to the rear of the motor and Ive heard the pump is in front of the passenger wheel somewhere. Is it hard to reach or do I have to take something apart to get to the pump. The times I looked I did t know where I was looking. But the y and the valves are something I can definitely do my self you think??? How complicated of a job it that?
HerbB

 

I still have warranty on my car until January. They say they cover lubricated parts in the engine block so I might be able to get my valve stem seals replaced with just a few hundred. Wish me luck I hope I can get that expensive repair done soon without having to drop 3000 or more. Might as well use my warranty while I still got it. If I can get that done all I have to worry about is the emissions problem I got.

 

I doubt that the check valves are bad, but the y-pipe could be damaged. Running the pump before removing the intake should help verify the bad pipe. The intake is a 5 out of 10 scale job, that takes around a 1 to 2 hours to remove. You will then have access to the y-pipe & the check valves. If you decide to remove the intake & remove the check valves, you can blow air into the ports in the heads. IF no air comes out of the tail pipes, the heads are plugged. Removing the check valves is a PITA.

 

Ok thanks I'll get up under the hood and explore

 

Unfortunately fixing this problem can be like a "dog chasing it's tail". You can spend hundreds of dollars and still not fix the problem.

i did have success getting my 2nd air and evap system to "ready" after trying the drive cycle procedure which is so stupid. If your not on a closed road course its hard to do. I'm going to look for a skilled NCS coder and look into getting coded to "euro"

A lot of info in the 7 series section.

http://www.bimmerfest.com/forums/showthread.php?t=587396&highlight=evap&page=2

 

Thanks I really need advice this is driving me crazy.
Do ccv valves cause your motor to burn oil if they are worn?

 

"When a crankcase breather valve begins to fail, engine drivability suffers. You may have a rough idle, hard start or a check engine light that is ON with fuel trim faults. If your engine is consuming oil or smoking, checking the crankcase vent valve is a good place to start. The crankcase breather has also been known to emit a honking or wheezing sound from the engine when failing. It is mounted to the back of intake manifold, near firewall. The crankcase vent hose that runs from the valve cover to the crankcase breather valve is the hose I find broken the most. If you are doing a repair where this hose may be moved or bumped, have a spare on hand, because it will break."

 

Thanks I'll look into all that. I need a good mechanic because a lot of corporate machinists just want the money and will say somethings broke just so they can do a fake repair and get a fatter check. I need all the advice I can get. I love my car but it's driving me crazy

 

2005 645ci 43K miles getting an error message about the secondary air system I realize this system should not be operating long after a cold start but I get the message after 30 to 45 minutes on the road ? Cleared it a couple of times but comes back, looking for an easy out it was suggested to change the gas cap i did it stayed away for a few days and returned.
Half a$$ed mechanically inclined but the electronic side is giving me fits, changed the thermostate a few miles ago but the message is different now referring directly to the secondary air system . no smoke or rough idle just the message . Thanks for any help I can get in advance.

 

SA only runs for less than a minute. It will not effect the motor after that period. There are usually 2 codes P0491, & P0492. P0491 is bank1 & P0492 is bank 2. The secondary air pump feeds air thru the y-pipe that goes under the intake, to the rear check valves. The check valves then allow air into the ports on the head to change the fuel to air ratio for a cold start. The pump is located directly in front of the passenger tire. With your car only having 43k miles, I suspect the y-pipe has come loose from one of the check valves.

I suggest jumping the SA pump to see what is going on with your engine. Once the pump is started, you can go to the exhaust tips to see if air is coming out of the exhaust. If air comes out one side & not the other, you at least know what bank has the problem. If the Y-pipe has come loose from one of the check valves, you will feel & hear air coming out from under the front of the bottom of the intake. If you feel or hear air, the pipe is either loose or cracked. The intake will need to come off to make the repair. The relay for the pump is located under the passenger side cabin filter. The control box has around 6 screws to remove to get the cover off.

 

Many Thx Herb I attached a pic of the codes I'm getting hopefully u can see it they are '29FE Secondary -air system' and '2A08 Secondary-air system 2'

I'm willing to dig into it I appreciate ur help as I don't want to damage it anymore than it is if any.

Thanks again

 

2 codes usually means that the pump is not working, or the Y-pipe has possibly cracked or come loose. You want the fan to run when the engine is off, to look for the problem. You can jump the fan at the pump, & the relay, or with the BMW software. At 43k miles, I would not think that your air ports in the heads are plugged. The parts diagrams are below.

http://bmwfans.info/parts-catalog/E63/USA/645Ci-N62/may2005/browse/engine/emission_control_air_pump/

http://bmwfans.info/parts-catalog/E63/USA/645Ci-N62/may2005/browse/engine/pollutant_reduction_pipes/

 

Thanks Herb earliest I can get on it is Sunday I'll let u know. Many thanks again

 

Herb getting this done just waiting on a piece of test equipment I ordered. If I went across the pump feed with a multimeter should I get a reading in the first minute of operation ? Just trying to eliminate the relay and harness , thx

 

That would just verify that you have voltage going to it. It will not tell you if it is running properly, or at partial speed. If you are going to gain access to the pump, just put 12 volts across it. You could use a jump box, or connect some jumper wires from the jump terminal. You really need to verify if your problem is the pump, or a possible bad y-pipe.

 

10 4 Herb will do. I have access to the pump and will run a jumper. , everything looks real good no corrosion etc very clean. Hope to have it resolved in the next few days. Cheers

 

Finally got test the pump and it failed ordered a new one , seems it's a pretty common thing Thx Herb

 

Once the pump runs, it will almost sound like a vacuum cleaner. Did you disconnect the harness from the pump & connect 12 volts to it, or jump it at the relay?

 

Just did this

I just did the jump and it was super simple, remove the bottom shield in the front and the side shield in front of the passenger tire, the pump is right there. Be careful with power junction, i snapped it off the vac pump, I think it slides out toward the passenger front tire. I used some romex I had laying around and jumped it. You will need another person to hear/feel the y pipe or someone at the end of the car to feel/hear any air movement. I hope your not clogged like I am (both banks), sounds like you shouldn't be based on your miles.

 

Used a power probe hook directly on the motor it ran for a couple of seconds and quit I reset and tried again got a red light checked my connections and set up tried again and it showed open motor being shot will replace this week Cheers

 

Lets hope this is your problem?

 

10 4 thx