Secondary Air Injection System: Insufficient Flow in Bank 1 and Bank 2
#1
05-17-2012, 12:45 PM
Secondary Air Injection System: Insufficient Flow in Bank 1 and Bank 2
Audi Guru's,
I have a 2001 Audi A6 with a 2.7T engine (65,000 miles) that recently fell victim to the following fault codes:
2 Faults Found:
17831 - Secondary Air Injection System; Bank 1: Insufficient Flow
P1423 - 35-00 - -
17819 - Secondary Air Injection System; Bank 2: Insufficient Flow
P1411 - 35-00 - -
Readiness: 0000 0000
In following up with a local Audi mechanic, he suggested starting with replacing the air pump as the fault is in both banks and the secondary air hose (part 17 in this diagram http://www.audiusaparts.com/parts/20...iagram=1351162) doesn't look cracked. Per his advice, I moved forward and replaced the secondary air pump with a brand new pump shipped straight from Bosch.
After the pump was replaced, the high-pitch noise (I suspect it was bearing going out in the secondary air pump) dissipated and it sounded like a hair dryer (the way it should) during a cold start. However, the fault came back after two cold starts.
Although these faults only regulate emissions and don't affect driving performance, I would like to get the fault cleared so the Check Engine Light (CEL) isn't staring at me every time I hit the road. My question for you Audi guru's is what would you replace next?
I was thinking about replacing the hose that connects to the secondary air pump (part 17 in the above link) as when I reconnected this hose back to the new pump it had a very loose connection. I tried putting a wire tie on it to see if I could keep the fault off but that didn't work (although the wire tie didn't look like it sealed the hose any better in all honestly). I do also remember that when I pulled this hose off the original pump it was very tight and took me a while to get off. For anyone who has replaced this pump, was this hose loose when connecting it to the new pump and did you end up replacing it? Also, if your recommendation is to replace this hose, is the procedure pretty straight forward? The rubber T branches the hose off to the right and left and it looks like some parts may have to be removed to get the old one out and the new one in.
I also noticed on the Rosstech site http://wiki.ross-tech.com/wiki/index...1/P1423/005155 that they state it could be the fuse or the solenoids. I am curious if anyone has experienced the solenoids or fuse going out to cause this fault? Although I haven't checked the fuse, I didn't suspect it was this because the problem was intermittent (I can generally get one successful cold start before the fault is reproduced). If you suspect it may be the Solenoids, please let me know how to check them.
Thank you in advance for all replies.
I have a 2001 Audi A6 with a 2.7T engine (65,000 miles) that recently fell victim to the following fault codes:
2 Faults Found:
17831 - Secondary Air Injection System; Bank 1: Insufficient Flow
P1423 - 35-00 - -
17819 - Secondary Air Injection System; Bank 2: Insufficient Flow
P1411 - 35-00 - -
Readiness: 0000 0000
In following up with a local Audi mechanic, he suggested starting with replacing the air pump as the fault is in both banks and the secondary air hose (part 17 in this diagram http://www.audiusaparts.com/parts/20...iagram=1351162) doesn't look cracked. Per his advice, I moved forward and replaced the secondary air pump with a brand new pump shipped straight from Bosch.
After the pump was replaced, the high-pitch noise (I suspect it was bearing going out in the secondary air pump) dissipated and it sounded like a hair dryer (the way it should) during a cold start. However, the fault came back after two cold starts.
Although these faults only regulate emissions and don't affect driving performance, I would like to get the fault cleared so the Check Engine Light (CEL) isn't staring at me every time I hit the road. My question for you Audi guru's is what would you replace next?
I was thinking about replacing the hose that connects to the secondary air pump (part 17 in the above link) as when I reconnected this hose back to the new pump it had a very loose connection. I tried putting a wire tie on it to see if I could keep the fault off but that didn't work (although the wire tie didn't look like it sealed the hose any better in all honestly). I do also remember that when I pulled this hose off the original pump it was very tight and took me a while to get off. For anyone who has replaced this pump, was this hose loose when connecting it to the new pump and did you end up replacing it? Also, if your recommendation is to replace this hose, is the procedure pretty straight forward? The rubber T branches the hose off to the right and left and it looks like some parts may have to be removed to get the old one out and the new one in.
I also noticed on the Rosstech site http://wiki.ross-tech.com/wiki/index...1/P1423/005155 that they state it could be the fuse or the solenoids. I am curious if anyone has experienced the solenoids or fuse going out to cause this fault? Although I haven't checked the fuse, I didn't suspect it was this because the problem was intermittent (I can generally get one successful cold start before the fault is reproduced). If you suspect it may be the Solenoids, please let me know how to check them.
Thank you in advance for all replies.
#3
05-17-2012, 02:51 PM
Eejimm,
Thank you for the recommendation. I will try that prior to replacing the hose. Have you heard of many having this caused by the fuse or solenoids? Also, would you know how to test the Solenoids?
Thanks for the reply.
Thank you for the recommendation. I will try that prior to replacing the hose. Have you heard of many having this caused by the fuse or solenoids? Also, would you know how to test the Solenoids?
Thanks for the reply.
#4
05-17-2012, 04:29 PM
I went down the same path with my SAI pump. I tried replacing the relay thinking that it was not even running and that didn't solve it.
I would suggest first checking to see if you have vacuum at the two rubber hoses connected to the combination valves at the back of each cylinder. it seems that vacuum is not being applied to the valves and they are not opening up, so no matter how much air the pump moves it is not getting where it needs to go so that the sensor sees it and doesn't trip a code. Either that, or both of your combi valves stopped working at the same time?
I would suggest first checking to see if you have vacuum at the two rubber hoses connected to the combination valves at the back of each cylinder. it seems that vacuum is not being applied to the valves and they are not opening up, so no matter how much air the pump moves it is not getting where it needs to go so that the sensor sees it and doesn't trip a code. Either that, or both of your combi valves stopped working at the same time?
#5
05-21-2012, 06:22 PM
I recently replaced the wire tie with a hose clamp and then had my hand on the rubber T hose to attempt and feel if any air was leaking out as someone started the car. It did not feel like any air was leaking and the Check Engine Light (CEL) didn't trigger so it appeared to have passed that test. I then started the car for a second cold start (I heard the pump kick in) and went for a long drive without the fault reoccurring.
However, after starting the car this morning (3rd cold start since the hose clamp), I put the car into reserve after the pump turned off and about 10 seconds later the CEL illuminated. The interesting thing is that when I had cleared the fault a few weeks ago (after placing the wire tie on the rubber T tube) the CEL occurred when I was in reserve after the 3rd cold start.
Does anyone have any hypothesis why I can get a few cold starts after clearing the fault as well as why the fault illuminates the CEL about 10 seconds after the pump stops? Additionally, threeputtpar how did you test if you had vaccum on the two hoses going into the back of the engine?
Thanks again for all the replies.
However, after starting the car this morning (3rd cold start since the hose clamp), I put the car into reserve after the pump turned off and about 10 seconds later the CEL illuminated. The interesting thing is that when I had cleared the fault a few weeks ago (after placing the wire tie on the rubber T tube) the CEL occurred when I was in reserve after the 3rd cold start.
Does anyone have any hypothesis why I can get a few cold starts after clearing the fault as well as why the fault illuminates the CEL about 10 seconds after the pump stops? Additionally, threeputtpar how did you test if you had vaccum on the two hoses going into the back of the engine?
Thanks again for all the replies.
#6
05-22-2012, 10:58 AM
Audi Guru's,
One other question that I had when placing the hose back onto the Secondary Air Pump was how far the hose should be put onto the pump's nozzle. As shown in the below linked picture (and attached) there are two ridges and then two taller nubs at the back of the nozzle. Is the hose supposed to fit all the way over the two nubs in the back or just the two little ridges before the nubs? I only put the hose around the two little ridges as I thought if it went over the two nubs in the back that it would leak around them (as there are gaps in the nubs around the nozzle).
Thanks
One other question that I had when placing the hose back onto the Secondary Air Pump was how far the hose should be put onto the pump's nozzle. As shown in the below linked picture (and attached) there are two ridges and then two taller nubs at the back of the nozzle. Is the hose supposed to fit all the way over the two nubs in the back or just the two little ridges before the nubs? I only put the hose around the two little ridges as I thought if it went over the two nubs in the back that it would leak around them (as there are gaps in the nubs around the nozzle).
Thanks
#7
05-22-2012, 11:02 AM
The hose should have a plastic pinch clip. The clip should click. Also the end of the hose should butt the plastic tab.
As for the vacuum lines, just trace the line from each combi valve to an actuator. It will look something like this.
Just replace the vacuum hose.
Most of the SAI incorrect flow codes are effects of broken vacuum lines.
As for the vacuum lines, just trace the line from each combi valve to an actuator. It will look something like this.
Just replace the vacuum hose.
Most of the SAI incorrect flow codes are effects of broken vacuum lines.
#8
05-22-2012, 11:05 AM
I recently replaced the wire tie with a hose clamp and then had my hand on the rubber T hose to attempt and feel if any air was leaking out as someone started the car. It did not feel like any air was leaking and the Check Engine Light (CEL) didn't trigger so it appeared to have passed that test. I then started the car for a second cold start (I heard the pump kick in) and went for a long drive without the fault reoccurring.
However, after starting the car this morning (3rd cold start since the hose clamp), I put the car into reserve after the pump turned off and about 10 seconds later the CEL illuminated. The interesting thing is that when I had cleared the fault a few weeks ago (after placing the wire tie on the rubber T tube) the CEL occurred when I was in reserve after the 3rd cold start.
Does anyone have any hypothesis why I can get a few cold starts after clearing the fault as well as why the fault illuminates the CEL about 10 seconds after the pump stops? Additionally, threeputtpar how did you test if you had vaccum on the two hoses going into the back of the engine?
Thanks again for all the replies.
However, after starting the car this morning (3rd cold start since the hose clamp), I put the car into reserve after the pump turned off and about 10 seconds later the CEL illuminated. The interesting thing is that when I had cleared the fault a few weeks ago (after placing the wire tie on the rubber T tube) the CEL occurred when I was in reserve after the 3rd cold start.
Does anyone have any hypothesis why I can get a few cold starts after clearing the fault as well as why the fault illuminates the CEL about 10 seconds after the pump stops? Additionally, threeputtpar how did you test if you had vaccum on the two hoses going into the back of the engine?
Thanks again for all the replies.
#9
05-24-2012, 08:59 AM
Hxgaser,
When you mentioned a plastic clip that clicks, are you referring to the clip on the end of each of the plastic tubes that go into the engine exhaust ports? Per the attached diagram, I am referring to the two tubes that branch to both export ports in part # 17. Thank you as well for confirming that the rubber T tube should butt up against the plastic tabs on the back of the air pump (as this is what I have done).
Additionally, when you state "actuator" is the Solenoid the same thing? If so, is there only one of these on the 2001 a6 2.7T and where is it located? I found this repair guide http://www.vaglinks.com/Docs/Audi/C5...aintenance.pdf for an A8 4.2L engine but am not sure if it is the same setup as my 2001 A6 2.7T engine. Prior to seeing this repair guide I was under the impression that the only hoses involved in the Secondary Air Injection System were part 17 in the attached pictures. However, now it looks like other hoses are involved and may be the culprit. Additionally, if there is only one actuator/Solenoid and this went out, it would make sense why both banks are reporting the fault. However, if there are two actuators/Solenoids I don't suspect this is the issue as it would be quite rare for both of them to go out at the same time.
Budhani786, I have not checked the fuse yet and I should (seeing how this would take less than 5 minutes), however given the symptoms in that I can get 1 to 2 cold starts without a fault, I wouldn't suspect it is a blown fuse. If the fuse were blown I would expect the CEL to illuminate after the first cold start when the fault is cleared.
Thanks again for all the replies.
When you mentioned a plastic clip that clicks, are you referring to the clip on the end of each of the plastic tubes that go into the engine exhaust ports? Per the attached diagram, I am referring to the two tubes that branch to both export ports in part # 17. Thank you as well for confirming that the rubber T tube should butt up against the plastic tabs on the back of the air pump (as this is what I have done).
Additionally, when you state "actuator" is the Solenoid the same thing? If so, is there only one of these on the 2001 a6 2.7T and where is it located? I found this repair guide http://www.vaglinks.com/Docs/Audi/C5...aintenance.pdf for an A8 4.2L engine but am not sure if it is the same setup as my 2001 A6 2.7T engine. Prior to seeing this repair guide I was under the impression that the only hoses involved in the Secondary Air Injection System were part 17 in the attached pictures. However, now it looks like other hoses are involved and may be the culprit. Additionally, if there is only one actuator/Solenoid and this went out, it would make sense why both banks are reporting the fault. However, if there are two actuators/Solenoids I don't suspect this is the issue as it would be quite rare for both of them to go out at the same time.
Budhani786, I have not checked the fuse yet and I should (seeing how this would take less than 5 minutes), however given the symptoms in that I can get 1 to 2 cold starts without a fault, I wouldn't suspect it is a blown fuse. If the fuse were blown I would expect the CEL to illuminate after the first cold start when the fault is cleared.
Thanks again for all the replies.
#10
05-24-2012, 11:02 AM
Actuator=solenoid... My bad. It is located pretty much underneath the y-pipe, back of the intake slightly to the passenger side. You should see an wire connector going to the top and a vacuum line going to it. Both the combination valves at the rear of the heads are controlled by this solenoid. If the vacuum line from the solenoid to the combination valves is damaged, the you will get that code. Also check the vacuum line from the solenoid to the source, which is the vacuum reservoir.
As for the clips, I was referring to a 2.8 set up, which has plastic clips attached to the hose. For 2.7, a hose clamp... Just push the hose until the end butts the tabs.
You may find the post #8 on this thread interesting...
http://forums.audiworld.com/showthread.php?t=1723357
As for the clips, I was referring to a 2.8 set up, which has plastic clips attached to the hose. For 2.7, a hose clamp... Just push the hose until the end butts the tabs.
You may find the post #8 on this thread interesting...
http://forums.audiworld.com/showthread.php?t=1723357