2.7t p1423 insufficient flow bank 1 only. Pump is good

[sline22]

I have checked the pump it's good since its only bank 1 one having the problem and the fuse in good. I only get the code on cold start if I dont let the car warm up for 15 min in the am. Checked for vacuum leaks and didn't find any. Could this just be a bad kombi/ egr valve causing my problems. I took it to a shop too and they said I had no leaks and the pump was in good shape. They could not make the mil light come on they said. I can every day if I start up and just drive off with out warming the car up. Anyone have any similar issues , thoughts ideas? Thanks.

[Audi4.2]

check your fuel filter?

[Calimus]

So this is what your getting?


17831/P1423/005155 - Secondary Air Injection System; Bank 1: Insufficient Flow
Possible Symptoms

Malfunction Indicator Light (MIL) active

Possible Causes

Fuse for Secondary Air Injection Pump blown
Vacuum Hose(s) leaky or collapsed
Piping between Secondary Air Injection Pump and Combi (Secondary Air Injection) Valve leaking
Secondary Air Injection Solenoid(s) faulty
Combi Valve(s) faulty

Possible Solutions

Check Fuse for Secondary Air Injection Pump
Check Vacuum Hose(s)
Check Piping between Secondary Air Injection Pump and Combi (Secondary Air Injection) Valve
Check Secondary Air Injection Solenoid(s)
Check Combi Valve(s)


Good chance it's the combi valve on that bank. They can be a bit wonky. I have a similar issue with my wife's 1.8t. It's the combi and it doesn't hurt anything, just annoying due to the CEL. It's one of those, "I'll get around to it one of these days" kinds of things. Been doing it for 2 years hasn't caused any problems. Oh yea, and I might get to it if she wasn't always burning up the roads with it :)

[sline22]

I put a new fuel filter in about 8 months ago. I have no vaccum leaks and the fuse is good. It it was the relay of selonoid I should get the fault in both banks correct? I'm thinking is the combi valve myself. Just want to narrow it down before I drop 240 on a new one. Tired of clearing that light when I take off on a cold start .

[Calimus]

I would think since it's limited to that bank, that it's all it could be. Anything else (Vac leak aside) should trip a code for both sides.

[sline22]

That's what I'm thinking. Gonna order one tonight and put it in this week. Keep you posted on what happens.

[sline22]

Just pulled the combi valve off. Had to make a custom 5mm Allen to get to it. I can't get the interals on the valve to move up or down. I should be able to depress it by hand right? Let me know thanks

[Calimus]

This I'm not sure of, but I would think so. If it's to be vacuum operated, you shouldn't have any trouble moving it by hand. If it's stuck open or closed, it will certainly cause the kind of issue you are having.

[sline22]

That's what I'm thinking it's stuck one way. I soaked it last night to try and get it to free up but when I got back to my shop this morning it was still solid.

[Siricospeed]

Yes, they move by hand. With a hand held vacuum pump, you should be able to actuate it and test. You can also push it open, place your finger over the vacuum port and see if it remains open. Don't forget to check the tubes from the solenoid to the valve, they tend to deteriorate with age. Lastly, the secondary o2 sensor is responsible for determining how much flow based upon how quickly the o2 levels jump when the pump is on. If your sensor is older, it may not be operating correctly.

[sline22]

I can't move it at all. Car has 100k on it now. Might be time to replace the sensors. Starting to wonder if it's even worth replacing these combi valves now or should I just do the sai delete ? I'm talking with someone as vast right now that can flash my ecu to get rid of the sai system. How hard is in to remove the system? Cars in my shop with the intake and bipipe off already and one combi already removed. Thought?

[sline22]

New kombi valve in and still the same code and I replaced the line from the valve to the pump. Still insufficient flow bank 1. Bank one is the passengers side correct? Also could a bad or sensor just be causing this? It should throw a code for a faulty sensor right?

[sline22]

Any ideas guys? This light is getting annoying. Maybe I'll just have to re flash my ecu and be done with it

[Audi4.2]

Bump

[Calimus]

I wish I had a combi system on my car so I could look at it and then visualize everything in my head. It could be that the combi being stuck cause an o2 to foul out which is why you are still getting the same error, but I really don't know. Someone on here has to have this system on their 2.7 since it should be there from 03' and up.

[blkrhyno]

Any ideas guys? This light is getting annoying. Maybe I'll just have to re flash my ecu and be done with it

I had mine coded out now the cel is gone, I'll remove the system when it gets a little warmer.

[sline22]

I wish I had a combi system on my car so I could look at it and then visualize everything in my head. It could be that the combi being stuck cause an o2 to foul out which is why you are still getting the same error, but I really don't know. Someone on here has to have this system on their 2.7 since it should be there from 03' and up.

That's what I was thinking ba 02 possibly cause I don't get a rough idle, no loss of power. Vacuum lines are good, pump has plenty of power. So maybe the faulty o2 sensor is just getting a low reading all the time. It's not always a hard code. I can scan ad have no light no code a few days later I can can same code but no light. The Sai system is expensive I don't wanna keep throwing money at it when I can spend 6-7 and get a reflash with an sai delete. I just really wanna know what it is tho

[sline22]

I had mine coded out now the cel is gone, I'll remove the system when it gets a little warmer.

Who reflashed ur ecu and coded it out?

[blkrhyno]

Who reflashed ur ecu and coded it out?

A fellow forum member, he goes by the name K0mpresd, PM him and he'll take care of you.

[sline22]

Sweet thanks a lot . Ill get ahold of him

[sureguy]

Everything for the SAI system is monitored by the front 02 sensors. Are you sure you are working on the correct bank? It is also possible but highly unlikely that the SAI ports on the bank could be coked up with carbon. Happens alot to other brands but never seen it on an Audi. I know you say the pump is running but is it making any pressure? I've seen the fan blades break and cause this. Just some food for thought. Do you have access to a VCDS cable? You could force the monitor and see how much flow there is.

[sline22]

I have checked for flow on both sides I disconnect the leads out off of the pump to the kombis and there is really good pressure and flow. From what i read p1423 code is the passenger side. maybe it's just a faulty o2 sensor reading throwing the insufficient flow code?

[Smokin' Joe]

Did you ever find a fix for this problem? I have exact same problem with my A6 that I need to dive into this weekend. Any help would be appreciated.

[Siricospeed]

Ok, the way this system sets a code is to monitor the pre cat o2 sensor and then post cat 02 sensor and compare while the pump is running. If the second 02 sensor (not responsible for engine performance) is not functioning properly, the catalitic converter (pre-cat) on that side is not warming up quickly enough to operate at peak efficiency. There are 3 things to consider: 1) The sai pump. solenoids and valves. 2) The 02 sensors and 3) Pre cat efficiency. (did you ever run around with a bad o2 sensor on that bank? How about a faulty coil? Either of these could have contaminated the pre-cat and this code will always come on!)

If this were mine, I would watch the 02 sensors on a scan tool during warm up. The second ones should level out really quickly with the pump on. If it takes too long, then the sensor may be bad. If the second 02 sensor on that bank mimics the primary, the cat is wiped.

Best of luck.

[sline22]

Thanks for the input! I'll give that a shot.