EGT DTC code and System too rich problem

[JohnS4]

Hi everyone,

I am having problems on my B5 S4 with the yellow engine management light appearing.

This started just before my 80k service so while it was in QST for the service they took a look and said it was logging a fault running rich and replaced the diverter valves (for the more expensive hyperboost ones as thats all they had in stock and I was keen to get my car back quickly)

However the light came back so I bought a cheap ebay vag-com cable and can see that 3 faults are being logged, 17537, 17862, and 17535. When they are cleared they come back again within a few days normally, though never immediately.

The logs are shown here:

******sep30 2008*****


VAG-COM Version: Release 409.1-US

Control Module Part Number: 8D0 907 551 G
Component and/or Version: 2.7l V6/5VT 0002
Software Coding: 10711
Work Shop Code: WSC 63351
Additional Info: WAUZZZ8DZ1A139188 AUZ7Z0A1797563
3 Faults Found:
17537 - Fuel Trim: Bank 2 (Mult): System too Rich
P1129 - 35-00 - -
17862 - Exhaust gas temperature sensor short 1 to ground
P1454 - 35-10 - Please Register/Activate - Intermittent
17535 - Long Term Fuel Trim mult.,Bank1 System too Rich
P1127 - 35-00 - Please Register/Activate

******* Sep 31 2008 *********

VAG-COM Version: Release 409.1-US

Control Module Part Number: 8D0 907 551 G
Component and/or Version: 2.7l V6/5VT 0002
Software Coding: 10711
Work Shop Code: WSC 63351
Additional Info: WAUZZZ8DZ1A139188 AUZ7Z0A1797563
3 Faults Found:
17862 - Exhaust Gas Temp Sensor 1 (G235): Short to Ground
P1454 - 35-10 - - - Intermittent
17537 - Long Term Fuel Trim mult.,Bank2 System too Rich
P1129 - 35-00 - Please Register/Activate
17535 - Long Term Fuel Trim mult.,Bank1 System too Rich
P1127 - 35-00 - Please Register/Activate


The car is a late jun 2001 model and standard with no remap. It has the hitachi MAF which I believe is less likely to go wrong from reading other posts here. The car doesn't feel down on power and when Kim the guy from QST drove it he said it felt like the power was good too.

I plan to get in contact with QST again but I know there are a lot of experts on this forum so wanted to get some advise here first.

If anyone can help with the following questions it will be much appreciated:

1/ Is driving the car in its current state likely to cause it any permanent harm ?

2/ Is the system too rich error likely to be caused by the EGT sensor problem or are they probably two seperate problems.

3/ From searching other posts it appears that EGT 1 is the drivers side and it looks easy enough to change, please can someone confirm this and also whether this is the black one (078919529F) or the red one (078919529G) as the vagparts site refers to them as LH and RH but that depends on which way you are looking at the engine !

Thanks in advance for any help.

John

[SJS]

Looks like EGT1 is shot. They overfuel slightly to keep engine temp down. How has your fuel economy been recently?

Not sure on the parts but someone will be along soon no doubt! The drivers side one is easy to get to though.

[JohnS4]

Looks like EGT1 is shot. They overfuel slightly to keep engine temp down. How has your fuel economy been recently?

Not sure on the parts but someone will be along soon no doubt! The drivers side one is easy to get to though.

Thanks for your reply, fuel economy has been about 22mpg recently but its a slow, stop-start journey to work, rarely getting above 4th gear so that doesn't seem unreasonable.

It sounds like its going to be a good plan for me to change EGT1 as a starting point and take it from there. Just need to know which one it is now !

[dazzer]

I would suggest you check your MAF out first. Log using VAG COM. The EGT failure may be the result of another underlying issue so until you have eliminated that or discounted a root problem then you could be wasting money just changing the EGT Sensor. Yes the Hitachi MAF is more reliable - not indestructable.

Hopefully they replaced your DVs because they were knackered, not because you were running rich.

[JohnS4]

I would suggest you check your MAF out first. Log using VAG COM. The EGT failure may be the result of another underlying issue so until you have eliminated that or discounted a root problem then you could be wasting money just changing the EGT Sensor. Yes the Hitachi MAF is more reliable - not indestructable.

Hopefully they replaced your DVs because they were knackered, not because you were running rich.

I have done 3 full throttle 3rd gear acceleration runs and included the logs from around 3000 rpm to 6500rpm below

It seems to max out at just below 230 g/s. Is this ok for an unmodified car ? (I'm assuming its unmodified as I have had it from 2.5yrs old and never modified it, plus the Audi dealer I bought it from never mentioned any mods).

Assuming these numbers are good, does this point back to the original problem of the EGT sensor ? Interestingly I checked the error codes after these runs and the same 3 are back but the engine management light is not. My previous comment about them taking a few days to reappear was based on checking after the light came on so they may have been there earlier.

As for the DV replacement, well I hope the old ones were knackered too as the replacements were quite a bit more pricy than the standard ones. The guy at QST seemed pretty knowledgeable about these cars and I was in a bit of a rush so I'll assume he did the right thing. At that time I didn't have a vag-com cable either so couldn't check the codes myself.
It was certainly a much better experience there than dealing with my local Audi dealers who are less than helpful so I wouldn't like this to appear as a criticism of the service I received there.

Thanks again for the people who have taken the time to read and help with this.


***** Run 1 *****


Wednesday,01,October,2008,13:36:35
8D0 907 551 G,,2.7l V6/5VT 0002,

,Group A:,'003,,,,Group B:, Not Running,,,,Group C:, Not Running
,,Engine speed,Mass air flow,Throttle angle,Ign timing,,,,,,,,,,
,TIME,,g/s,0-5deg=closed,deg,TIME,,,,,TIME,,,,
Marker,STAMP, /min, g/s,%, BTDC,STAMP,,,,,STAMP,,,,

,15.48,2560,116.50,100.0,9.8,,,,,,,,,,
,15.88,2720,129.81,100.0,9.0,,,,,,,,,,
,16.28,2920,132.83,100.0,9.0,,,,,,,,,,
,16.70,3080,141.64,100.0,11.3,,,,,,,,,,
,17.10,3240,150.06,100.0,12.0,,,,,,,,,,
,17.52,3400,155.17,100.0,11.3,,,,,,,,,,
,18.00,3600,161.11,100.0,12.0,,,,,,,,,,
,18.41,3800,167.64,100.0,13.5,,,,,,,,,,
,18.81,3920,173.14,100.0,13.5,,,,,,,,,,
,19.21,4080,181.53,100.0,12.0,,,,,,,,,,
,19.63,4240,186.03,100.0,10.5,,,,,,,,,,
,20.04,4400,185.83,100.0,11.3,,,,,,,,,,
,20.46,4560,191.14,100.0,9.8,,,,,,,,,,
,20.88,4720,195.86,100.0,9.0,,,,,,,,,,
,21.32,4880,201.00,100.0,11.3,,,,,,,,,,
,21.76,5000,205.75,100.0,11.3,,,,,,,,,,
,22.22,5160,211.42,100.0,11.3,,,,,,,,,,
,22.67,5320,213.97,100.0,11.3,,,,,,,,,,
,23.12,5480,217.17,100.0,10.5,,,,,,,,,,
,23.60,5600,219.25,100.0,13.5,,,,,,,,,,
,24.06,5720,221.83,100.0,10.5,,,,,,,,,,
,24.54,5880,225.14,100.0,15.0,,,,,,,,,,
,25.02,6000,224.89,100.0,15.8,,,,,,,,,,
,25.52,6120,226.22,100.0,12.0,,,,,,,,,,
,26.01,6200,229.36,100.0,12.8,,,,,,,,,,
,26.51,6360,229.36,100.0,17.3,,,,,,,,,,
,27.00,6480,228.47,100.0,17.3,,,,,,,,,,
,27.52,6560,225.25,100.0,19.5,,,,,,,,,,


**** Run 2 *****


,129.25,2680,73.53,100.0,23.3,,,,,,,,,,
,129.64,2840,105.14,100.0,21.0,,,,,,,,,,
,130.04,3000,145.50,100.0,15.0,,,,,,,,,,
,130.46,3200,155.83,100.0,12.0,,,,,,,,,,
,130.86,3400,160.25,100.0,12.8,,,,,,,,,,
,131.26,3600,169.81,100.0,12.0,,,,,,,,,,
,131.76,3840,176.50,100.0,12.8,,,,,,,,,,
,132.17,4040,186.86,100.0,10.5,,,,,,,,,,
,132.57,4200,190.47,100.0,12.0,,,,,,,,,,
,132.99,4400,193.78,100.0,12.8,,,,,,,,,,
,133.42,4600,201.61,100.0,12.0,,,,,,,,,,
,133.95,4840,205.31,100.0,14.3,,,,,,,,,,
,134.38,5000,209.06,100.0,15.0,,,,,,,,,,
,134.83,5200,213.47,100.0,12.0,,,,,,,,,,
,135.29,5360,217.00,100.0,15.8,,,,,,,,,,
,135.76,5520,220.53,100.0,16.5,,,,,,,,,,
,136.24,5720,223.14,100.0,14.3,,,,,,,,,,
,136.72,5880,225.14,100.0,15.0,,,,,,,,,,
,137.20,6000,227.44,100.0,15.8,,,,,,,,,,
,137.68,6160,229.81,100.0,16.5,,,,,,,,,,
,138.17,6320,230.69,100.0,18.0,,,,,,,,,,
,138.70,6480,226.67,100.0,20.3,,,,,,,,,,
,139.18,6600,225.69,100.0,21.8,,,,,,,,,,
,139.69,6720,225.25,100.0,21.0,,,,,,,,,,

***** RUN 3 *******


Wednesday,01,October,2008,13:46:58
8D0 907 551 G,,2.7l V6/5VT 0002,

,Group A:,'003,,,,Group B:, Not Running,,,,Group C:, Not Running
,,Engine speed,Mass air flow,Throttle angle,Ign timing,,,,,,,,,,
,TIME,,g/s,0-5deg=closed,deg,TIME,,,,,TIME,,,,
Marker,STAMP, /min, g/s,%, BTDC,STAMP,,,,,STAMP,,,,
,181.83,2880,107.17,100.0,19.5,,,,,,,,,,
,182.33,3040,149.06,100.0,12.0,,,,,,,,,,
,182.73,3240,155.00,100.0,12.0,,,,,,,,,,
,183.13,3360,157.61,100.0,12.8,,,,,,,,,,
,183.54,3560,168.72,100.0,12.0,,,,,,,,,,
,184.05,3760,177.36,100.0,12.0,,,,,,,,,,
,184.55,3960,183.75,100.0,11.3,,,,,,,,,,
,184.95,4120,187.50,100.0,11.3,,,,,,,,,,
,185.46,4320,192.03,100.0,12.0,,,,,,,,,,
,185.88,4480,194.08,100.0,11.3,,,,,,,,,,
,186.29,4640,199.17,100.0,13.5,,,,,,,,,,
,186.73,4800,204.06,100.0,14.3,,,,,,,,,,
,187.19,4960,206.53,100.0,15.0,,,,,,,,,,
,187.62,5080,209.06,100.0,11.3,,,,,,,,,,
,188.07,5240,213.47,100.0,15.0,,,,,,,,,,
,188.53,5400,217.81,100.0,12.8,,,,,,,,,,
,189.00,5520,219.56,100.0,13.5,,,,,,,,,,
,189.46,5640,222.69,100.0,14.3,,,,,,,,,,
,189.94,5760,224.47,100.0,14.3,,,,,,,,,,
,190.42,5920,226.67,100.0,15.0,,,,,,,,,,
,190.90,6040,226.22,100.0,18.0,,,,,,,,,,
,191.40,6160,227.11,100.0,18.0,,,,,,,,,,
,191.89,6240,228.47,100.0,17.3,,,,,,,,,,
,192.39,6360,228.47,100.0,20.3,,,,,,,,,,
,192.89,6480,229.81,100.0,21.0,,,,,,,,,,
,193.40,6560,227.92,100.0,19.5,,,,,,,,,,
,193.91,6640,225.25,100.0,22.5,,,,,,,,,,
,194.41,6720,227.03,100.0,21.0,,,,,,,,,,

[curtis11]

are you sure the car is unmodified ?
the airflow is well above standard which is usually around 212.

egt you need is the black one, the brown one will not be long enough.

the system running rich is most likely the egt, if the maf was screwed it would not be going so well.

driving the car will be fine aslong as you plan to get it fixed quite soon.

get the egt and do some more logs and i think she will be fine

[dazzer]

are you sure the car is unmodified ?
the airflow is well above standard which is usually around 212.

egt you need is the black one, the brown one will not be long enough.

the system running rich is most likely the egt, if the maf was screwed it would not be going so well.

driving the car will be fine aslong as you plan to get it fixed quite soon.

get the egt and do some more logs and i think she will be fine

yeah MAF is very good - theoretical HP of 287. Probably just got a good'n!

[JohnS4]

Thanks for the help, I will get a new EGT sensor ordered up in the next few days and hopefully that will fix the problem.

Is there anyway to know for sure if the car has been modified, I'm fairly sure it hasn't but as I haven't had it from new it would be interesting to check.

[craigg]

would the high AFM readings on a standard car not point to a possible boost leak?

The afm reading would be higher as some of the air is leaking out, the engine would fuel for the air it has seen thru the meter and therefore would be running rich...

[curtis11]

best way is to check through vagcom and see what boost the car is running it would also rule out a boostleak, but i dont think you can run this log on the ebay cables as it is not available.

[craigg]

the boost pressure might not actually be below whats demanded,

it just means that the turbo is drawing in more air to achieve the desired pressure which would make it run rich...

also, you can do the logging with the cheap ebay cables, you just need the correct version of vagcom.

[JohnS4]

I dont think I have an air leak because I just checked my receipt for the 80k service that was done a couple of weeks ago and it says that the air leak test was ok.

It definitely looks like the EGT sensor is faulty even if its not the only problem. I plan to order one up today and replace that first then keep a close eye for any more errors that get logged to see if there is anything else that needs attention.

Is it possible that the MAF could be reading higher than the actual airflow and that could be causing the rich running ?

Lastly assuming that I get the right version of vag-com software (or the official cable), what are the best measuring blocks to log to check for boost pressure ?

Thanks

John

[Blue_Thunder]

Block 115 shows requested and actual boost

[JohnS4]

Hi Everyone,

I changed the EGT1 sensor on Saturday and cleared the codes and drove around yesterday without the yellow engine management light appearing, however this morning during a short trip to work the yellow light appeared again and after checking the codes again I still see the system too rich errors and am now getting a different error code on the same EGT sensor.

Has anyone got any more suggestions what I can try to fix this as I'm getting desperate to fix it now.

When I posted the MAF figures earlier in this thread they were higher than expected - could this be the problem, maybe the MAF is reading high and causing the system too rich problem ?

I have read from other threads that if the fuel mixture is too lean it can damage the EGT's, is this also true if the system is too rich ? The last thing I want to do is to damage the new EGT. What does implausible signal mean anyway - I'm guessing it means outside the expected range ?

The error codes are below. I hope someone can help me with this, thanks for your time.

VAG-COM Version: Release 409.1-US

Control Module Part Number: 8D0 907 551 G
Component and/or Version: 2.7l V6/5VT 0002
Software Coding: 10711
Work Shop Code: WSC 63351
Additional Info: WAUZZZ8DZ1A139188 AUZ7Z0A1797563
3 Faults Found:
17863 - Exhaust Gas Temp Sensor 1 (G235): Implausible Signal
P1455 - 35-10 - - - Intermittent
17537 - Fuel Trim: Bank 2 (Mult): System too Rich
P1129 - 35-00 - -
17535 - Fuel Trim: Bank 1 (Mult): System too Rich
P1127 - 35-00 - -

[The_Nich]

phone lucas at mrc and get a health check