P0491 & P0492 Secondary Air Injection System Insufficient Flow
#1
AudiWorld Junior Member
Thread Starter
P0491 & P0492 Secondary Air Injection System Insufficient Flow
I have these two codes that I can't get rid of. I know it has something to do with the air pump. I read some info about this, but I'm not sure if that applies to my 2012 s4.
there are a few ways to check if the pump is in working condition. 1) when the engine is cold, start the car and turn it off after 2 sec - you should hear the pump working after that? 2) do an output test using VAG
I'm gonna try these two options, but what if I don't hear the pump? Can I remove it and apply 12V directly to it, and see if it works? I also read about 40A fuse and a relay for it, but I wasn't able to find where it is located.
Any help is appreciated!
there are a few ways to check if the pump is in working condition. 1) when the engine is cold, start the car and turn it off after 2 sec - you should hear the pump working after that? 2) do an output test using VAG
I'm gonna try these two options, but what if I don't hear the pump? Can I remove it and apply 12V directly to it, and see if it works? I also read about 40A fuse and a relay for it, but I wasn't able to find where it is located.
Any help is appreciated!
#2
AudiWorld Junior Member
Thread Starter
ok so I started the car on the cold engine, turned it off - didn't hear anything.
Tried doing an output test using VAG, couldn't find the module to perform the test on. Looked in the basic settings and output test sections - nothing is there that corresponds to air pump. Anybody know how to do an output test of air pump on 2012 s4 using VAG?
Tried doing an output test using VAG, couldn't find the module to perform the test on. Looked in the basic settings and output test sections - nothing is there that corresponds to air pump. Anybody know how to do an output test of air pump on 2012 s4 using VAG?
#6
Sorry to bump an old thread, my 2011 S4 just popped up the engine light today, used ODB and found these same two codes. The second one being "intermittent" (P049200), the first one showing a red fault (P049100).
I may not be able to get it to a mechanic for a few days, how significant is an air pump issue? I'm in Toronto Canada so fairly cold these days.
I may not be able to get it to a mechanic for a few days, how significant is an air pump issue? I'm in Toronto Canada so fairly cold these days.
#7
Also had a third fault show up as intermittent, being the Gateway / Energy Management active, fault code 03041 ... so will need to check that as well.
Of course my incoming new vehicle is now slated to be 60 days late, so hoping to not have to spend much on this!
Of course my incoming new vehicle is now slated to be 60 days late, so hoping to not have to spend much on this!
Trending Topics
#8
Okay, so looks like "all" it does is basically pump air into the exhaust to help with emissions, so not critical to driving the car....but likely a challenge in passing an emissions test. A mechanic literlaly just had to fix the hangers on my catalytic converter pipes as they rusted and fell off, I'm wondering now if when they did that something happened to the SAI. Seems odd, since the hangers are under the car so maybe just a coincidence?
Anyone know generally where the hose is I should be checking for below?
Anyone know generally where the hose is I should be checking for below?
Last edited by pbcsd; 02-28-2022 at 01:03 PM.
#9
I believe the relay and fuse for the SAI Air Pump is located in the ECU weatherproof box, at the base of the windshield, rear of engine compartment, drivers side, below the black plastic cowl cover.
There is no detriment to the engine, or how it drives, if you don't get this fixed. When SAI doesn't work properly, it only delays the time that the catalytic converters take to start converting exhaust gas compounds to less environmentally harmfull compounds. This delay only happens at a cold start, as the cats need to be hot before they "work". The SAI system injects air so that the extra gasoline hydrocarbons burn as they pass thru the exhaust manifold into the cat, heating them up quicker.
There is no detriment to the engine, or how it drives, if you don't get this fixed. When SAI doesn't work properly, it only delays the time that the catalytic converters take to start converting exhaust gas compounds to less environmentally harmfull compounds. This delay only happens at a cold start, as the cats need to be hot before they "work". The SAI system injects air so that the extra gasoline hydrocarbons burn as they pass thru the exhaust manifold into the cat, heating them up quicker.
Last edited by S4'ed; 03-08-2022 at 10:22 AM.
#10
I believe the relay and fuse for the SAI Air Pump is located in the ECU weatherproof box, at the base of the windshield, rear of engine compartment, drivers side, below the black plastic cowl cover.
There is no detriment to the engine, or how it drives, if you don't get this fixed. When SAI doesn't work properly, it only delays the time that the catalytic converters take to start converting exhaust gas compounds to less environmentally harmfull compounds. This delay only happens at a cold start, as the cats need to be hot before they "work". The SAI system injects air so that the extra gasoline hydrocarbons burn as they pass thru the exhaust manifold into the cat, heating them up quicker.
There is no detriment to the engine, or how it drives, if you don't get this fixed. When SAI doesn't work properly, it only delays the time that the catalytic converters take to start converting exhaust gas compounds to less environmentally harmfull compounds. This delay only happens at a cold start, as the cats need to be hot before they "work". The SAI system injects air so that the extra gasoline hydrocarbons burn as they pass thru the exhaust manifold into the cat, heating them up quicker.