Trouble Codes

[A. C. E.]

I am helping my friend out with his 2005 Carrera S Cab - 6 speed. He just put it back on the road after winter storage. The battery was disconnected. I advised him to take it for a long drive. Initially, the idle was "hunting" and sometimes early on it would stall but that is no longer the case. It now runs smoothly. He does have a Durametric Pro and so do I, but since he has a Cab and it was sunny out (it was tough seeing the laptop screen), I used my LAUNCH.

 

Codes that came up: 

P2177 - Oxygen Sensing Adaptation (FRAU) Bank 1 Lower Load Range

P2179 - Oxygen Sensing Adaptation (FRAU) Bank 2 Lower Load Range

P2187 - System Too Lean At Idle Bank 1

P2189 -  System Too Lean At Idle Bank 2

 

I deleted the codes and off he went, but speaking to him this morning, a CEL came back on. I haven't had a chance to connect to the car since.

 

Now this may still be the result of the Readiness test not being complete, even though he drove about 30 miles.

I also have not looked into the engine compartment to see is a vacuum line if off (most noticeable at idle).

 

I also got a Data Fuel Trim Adaption (did they mean Adaptation)  Lower Load (FRAU) b1 and b2 of 0.999268 and 0.999909.

What do those numbers represent? If that is a Lambda number, great, but that is a guess. It was slightly lower when the car was cold and started up 0.892181 and 0.820152 and if that is a Lambda number I can understand it running richer initially. Fuel Trims are normally in percentages.

 

By the way, I am sure some of the experts here know what FRAU, RKAT, RFAO and more of these acronyms stand for. Is there a list somewhere?

Edited April 9, 2021 by A. C. E.

[JFP in PA]

Welcome to RennTech 

P2177 Oxygen Sensing Adaptation, Lower Load Range, Bank 1 (FRAU1) – Above Limit

 

Possible fault cause

- Intake air system leaking

- Leaking exhaust system (draws fresh air)

- Incorrect main charge signal from MAF sensor

- Fuel pressure too low

- Fuel injector(s) mechanically faulty (sticks)

- Volume supply of fuel pump too low

 

P2179 Oxygen Sensing Adaptation, Lower Load Range, Bank 2 (FRAU2)

 

- Above Limit Possible fault cause

- Intake air system leaking

- Leaking exhaust system (draws fresh air)

- Incorrect main charge signal from MAF sensor

- Fuel pressure too low

- Fuel injector(s) mechanically faulty (sticks)

- Volume supply of fuel pump too low

 

Since this affects both banks - it looks like you likely have an air leak.

[A. C. E.]

3 minutes ago, JFP in PA said:

Welcome to RennTech 

 

Since this affects both banks - it looks like you likely have an air leak.

I've been on Renntech now and then for about a decade.

 

Spot on and exactly what I was thinking. It is hard to get a hold of my friend and his 997. He isn't very technically inclined, so this will be left to me.

 

I might look at his AOS as well since it is original. His 997 has about 110,000 miles on it.

[JFP in PA]

Worse comes to worse, you can always smoke test the intake looking for leaks.  You can also test the AOS unit with a digital manometer.  Good luck!

[Silver_TT]

110K miles on it and it's still the original AOS?  I agree with JFP about testing it with a digital manometer but honestly at that mileage if you are sure it's the original I would replace that preemptively.  Even if you don't have a ton of blow by and the engine is healthy that is a lot of mileage on that diaphragm (oil and fuel additives are hard on it, they even revised the material related to this to help it last longer and be more durable), I can't imagine it's in very good shape. 

 

It's better to catch these before they start to fail for numerous reasons.... it's not really a fun job on that car if you asked me, but I would still prioritize it and get it done.

 

Also on your question about fuel trims, this video will answer all your questions:

 

This will also be helpful in the context of this thread:

 

Edited April 10, 2021 by Silver_TT

[A. C. E.]

Good info JFP and Silver_TT!

 

I bought some of the components to make a smoke machine but haven't been able to get to the hardware store to get the rest of the items.

 

As for a manometer, I have one on order. I can use it for other purposes as well.

[Silver_TT]

I built this for $47 and have been using it on my car since I replaced the AOS.  I plan to monitor it every ~6 months or so to study the signal over time and help me know when I could have a vacuum leak, in the AOS for example.  I will still do the AOS every 50K miles regardless because a marginal one can affect your engine's health or even destroy an engine if the vacuum is too high.

 

A lot of times you will see these devices being sold as HVAC devices but these can have multiple purposes as you say.  You can use it on multiple cars as long as you have the gas cap fitting made for it.  One important thing to note is that the spec vacuum level can vary widely.  Very generally speaking older pre-DFI models like the 2005 Carrera S will run a lower signal of vacuum (~5" H20) where as the DFI cars can run 15" H20 or even much higher.  For example my 2014 Audi 2.0T runs vacuum of 35-40" H20 after being bumped up by Audi several years after the initial spec.  A lot of people say you can just use a standard pressure gauge in " Hg but this is not an accurate measure and should not be used especially on cars with lower levels of vacuum like 5" where a pressure gauge will not provide the accuracy required.

 

They are building a new racetrack where I live and I am considering buying a new track car to go with it.  When that time comes, I will use the manometer to keep that car healthy as well.

 

 

[A. C. E.]

On 4/13/2021 at 8:36 AM, Silver_TT said:

I built this for $47 and have been using it on my car since I replaced the AOS. 

 

I am doing the same. My manometer will be here by the weekend. All I need to do is make the connection to the oil filler cap.

 

I was over at my friend's place yesterday and ran my code reader on it again after some codes popped up again. It looks like he has two less codes on the Readiness cycle since last week. All that is left stating "Not Ready" is the Evaporative System and Secondary Air Injection. I don't know his 997 or my own 991.1 GTS like I know my 993 (like the back of my hand).

 

I had a quick look in his engine compartment and this is what I noticed. Nice that you can see an engine, unlike my 991.1.

 

Notice the damp oil residue at the intake plenum and throttle. Time to take it apart, check seals and the AOS.