Diagnostics Advice Please.

[sadieandjim]

Hi Guys
Started the car up a week ago and the dreaded engine management warning light stayed lit. Took it to my local independent Audi/Vw garage and they ran a diagnostic on it. Got the following codes:

17863 Exhaust Gas Sensor 1. G235. P1455
17831 Secondary Air Inj Sys Bank 1. P1423
17819 Secondary Air Inj Sys Bank 2. P1411

They mean absolutely nothing to me as I'm not very mechanically minded, although I'm picking a lot up from reading this site religiously. I hope some of you lot could give me a clearer picture of what the faults mean and what my course of action should be. Are they all connected?

I've only had the car for 7 weeks and it has a chocolate box warranty which I would like to get something out of if possible (£1000 max claim). Are these faults, a warranty issue, and what is my best line of approach with the warranty provider?

The guy whom I spoke to at the garage was confident that they could sort any faults and I would like to give them a chance as they have been good to me in the past. Do you guys think these faults are main dealer or specialist problems?

I've been away since the day the codes were downloaded and on driving the car for the first time yesterday and today the light has stayed out. Does that mean it was an intermittent fault or is it still there? Do I wait for it to happen again or deal with it ASAP? The car feels the same as it did the day I picked it up, so I dont think the performance is suffering but having said that I only had a TDI Avant before that so it could be a case of not knowing any better.

I would really appreciate all of your views on this so I can make the right choice.

Regards

[Rich_C]

I would guess that the auxiliary air pump has failed. The first time it happened to me the engine light came on and stayed on but the car was unaffected. The pump is purely there to help with emissions on cold start-up.

Do you get any strange noises on start-up that go away after a couple of minutes?

To get a dealership to change the air pump will cost you in the region of £350.

Rich.

[GardinerG]

Hi, I would suggest posting this in the DTC/VAG forum for more help on this. The Ross-Tech guys frequent this forum and often give advice.

As for what these mean, here's some more info:

P1455 17863 Sensor -1- for exhaust temperature -G235
Implausible signal

P1423 17831 Bank 1, secondary air system
Through-flow too low 1)
Check secondary air injection pump fuse.
Check vacuum hoses.
Check hose from pump to secondary air injection valve.

P1411 17819 Bank 2, secondary air system
As for P1423.

1) In response to these faults the engine control module only activates the exhaust emissions warning lamp (MIL) if the fault is detected again on two subsequent engine starts.

So, check the fuse(s) (fuse 17, 13 fold relay panel / fuse 7 E box 3 fold relay panel), check vacuum hoses and check the hose from pump to secondary air injection valve.

Lastly, without meaning to scare monger, replacing the EGT (G235) if it turns out to be faulty is an engine out job by the manual.

Sorry if that was all gibberish but the secondary air pump is fairly minor and easy to fix/replace. I would get the air pump sorted then see if the EGT error comes back after being cleared. I honestly don't know if the EGT error would be connected with the others.

[Rich_C]

Also worth checking to see if the pump hoses are split/perished. If you change the auxiliary air pump it's probably worth doing the hoses at the same time for the extra couple of quid it costs.

Rich.

[kbee]

hi i agree with previous posts exhaust sensor fault is probably due to low cold start flow and will prob never return when pump is fixed,however if it is permanent then sadly engine out 15hrs min sorry, had 2 myself

[grizz]

Where are you , If the pump is working it'll be the small pipes that control the flow .
As for the egt sensor, i know they can be changed with the engine in place.g

[GardinerG]

i know they can be changed with the engine in place.g

Grizz, I've done these on the 2.7T APB A6, but this was a PITA. I would love to know for future ref how you do them on the 4.2T BCY without dropping the engine!?!

[grizz]

Sorry it's a secret .... ok as it's you. All you have to do is --------pm sent .

[sadieandjim]

Thanks for all of the advice regarding the engine management faults, and sorry for the late reply guys. Been away working for a couple of weeks and had the car with me.

The light came on again this week and so at present it's in with the local audi independents. They seem to be in agreement with you lot and are at present trying to locate any splits or leaks in the hosing, although they reckon its a bit of a faff. Do you reckon I should get the pump replaced anyway, or wait to see if new hosing sorts the problem?

Thanks again for the advice, its much appreciated from a technical idiot. At least it gives me a bit of a heads up when I talk to the guys at the garage.

Grizz and Rich you have PM.

[imolas4uk]

i can change EGT`s and both pairs of lambda with the rs6 engine in situ