Help with diagnosis

B8 S4
#1

Okay… as you may know I’ve been complaining about some tranny issues (1-2 shift) during the last drag strip meet. Well since that day I’ve noticed my car seems to be riding rough (it lags a bit in the lower RPM range and seems to vibrate more than usual but does NOT rough ideal) and even felt as though it was about to stall at one point (imagine starting your lawnmower for the first time after winter)!

My first thought was to check the CEL codes, but only had one CEL that related to an O2 sensor which I suspect is a result of loose spacer/O2 sensor connection.

Second thought was the new Eurocode sway’s and drop links but not sure what I’d be looking for if these were the problem?

Third thought relates to tire ware as these tires are getting to a point where they probably should be changed though I don’t know if balding tires could cause this vibration issue?

Fourth, which was actually my first thought, relates to the tranny itself though again not sure what I can do to diagnose if there is no fault codes?

Can anyone help me think this sucker through or maybe offer recommendations on how to use the vagcom cable to diagnose the problem further than looking at CEL fault codes?

I would take it to the dealer but with all the TD1 talk I figured I’d try the brain trust over here first.

Thanks guys!

#2

whats the code on the O2 sensor? a bad O2 sensor code give you the hesitation/roughness

#3

Yeah, good point. Post that code. o2 sensors control quite a bit and can easily cause these issues.

#4

Thanks for the input guys!

I eliminated the O2 CEL as a cause because the CEL appeared several times over the course of two months prior to me noticing the current performance issues. I also did a bit of research on these CEL’s and it seem to support my theory of a loose O2 spacer as the cause.

Do you still think it could be the cause of my performance issues?

Address 01: Engine (J623-CCBA) Labels: 06E-907-551-CAK.clb
Part No SW: 8K0 907 551 A HW: 8K0 907 551 A
Component: 3.0T SIMOS84 H06 0002
Revision: --------
Coding: 0104000A240F0128
Shop #: WSC 06325 000 00000
ASAM Dataset: EV_ECM30TFS8K0907551A A01003
ROD: EV_ECM30TFS8K0907551A.rod
VCID: 2F67175F76066D1

2 Faults Found:
6429 - Oxygen (Lambda) Sensor B1 S2
P0136 00 [104] - Malfunction in Circuit
Intermittent - Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 7
Mileage: 42852 km
Date: 2012.03.15
Time: 21:12:13

6430 - Oxygen (Lambda) Sensor B2 S2
P0156 00 [096] - Malfunction in Circuit
Intermittent - Not Confirmed - Tested Since Memory Clear
Freeze Frame:
Fault Status: 00000001
Fault Priority: 2
Fault Frequency: 1
Mileage: 44538 km
Date: 2012.04.15
Time: 00:26:57

#5

so those are post cat O2s, may cause a bit of hesitation but shouldnt be major. Since they are intermitent try clearing them and see if they come back/the hesitation clears up

#6

Good idea! I will clear the codes and see if that helps lean things out.

My intention was to remove the spacers at the same time as upgrading my tune to APR’s V2 but I haven’t heard any new news on the dealer enabled flashing, even though it’s April and they said we should have it available in April…

#7

what spacers are they? matt/voltron had lots of trouble with his spacers I believe.

Strange that APR doesn’t tune out a catalyst efficiency code for guys who run catless or HFC. What’s with that?

p.s. you’re getting ‘malfunction in circuit’, not the efficiency code.

Doesn’t look like a spacer not working right, does it? You’re also getting it on BOTH o2 sensors that are POST cat.

Here’s an explanation of the malfunction in circuit code from http://www.obd-codes.com/p0136

[quote]What does that mean?Essentially the same as P0137, a P0136 code refers to the second oxygen sensor on Bank 1. The O2 oxygen sensor produces a voltage between .1 mV and .9 mV. The ECM monitors O2 sensor voltage and determines if exhaust is lean or rich. O2 sensor voltage is high when exhaust is rich and low when exhaust is lean. The ECM monitors this voltage and increases or decreases fuel injector pulsewidth according to engine fuel/air ratio. If the ECM detects low HO2Sensor voltage for an extended period, it will set P0136 Conditions required to set: HO2 sensor voltage is low for longer than 2 minutes (minutes depend on model of vehicle. Could be up to 4 minutes)

SymptomsThere may be no visible symptoms to the driver. Poor fuel mileage, possible misfire, depending on O2 sensor position when sticking.

CausesA code P0136 may mean that one or more of the following has happened:

Faulty O2 sensor leak in exhaust close to O2 sensor
Short to voltage on O2 signal circuit
Open in circuit resistance caused by corrosion in connector
Possible SolutionsReplace the second oxygen sensor on bank 1
Repair open or short in signal circuit
Clean corrosion from connector
[/quote]

#8

if the spacer is loose and leaking its going to let O2 poor air out/O2 rich air in on the exhaust side of the O2 sensor, this should decrease the voltage it produces

#9

so o2 rich air in leans out the mixture and produces a low voltage reading, then the code?

so where can you see the voltage that triggered the code? Doesn’t really say ‘too high’ or ‘too low’ or give any reading above. Just says malfunction in circuit.

#10

vagcom can read out O2 voltages, there are plenty of calibration curves to check against, or you can log lambda desired and lambda actual and let the ecu do the math.

Rich = higher voltage (more driving force for the O2 to cross into the exhaust stream), lean = lower voltage (O2exhaust ~ O2atm, no driving force, no voltage)

#11

its crazy how complicated those little fuckers are. No wonder they crap out.

I may have mentioned it before, but I was watching 2 guys garage and they had a C5 vette in for a refresh. One thing they did was install 4 new o2 sensors just to make sure everything was top notch. I thought it was an interesting piece of maintenance that just about nobody I’ve seen before does.

#12

Sak,

you are correct it’s not a cat efficiency code its a malfunction code.

Last time this happened it was explained to me that the spacers (034 motorsports at the time) were installed in a way that had the sensors upside down. Being upside down water would pool on them causing them to malfunction which led to the corresponding fault codes. They removed the spacers, dried the sensors, and reinstalled them and all was good.

A few weeks went by and I was testing the ECU program switch and noticed I had fault codes after switching to stock mode. Spoke to Arin at APR and he said the efficiency codes would always be there, what the testpipe file does is remove the check engine light on the dash. However, in stock mode your check engine light will come on as if it doesn’t, and the dealer notices your car has testpipes/HFC, it would be a sure sign that you have a tune on your car and could put your powertrain warranty in question. So I decided to install the Stratmosphere spacers so that I could avoid the check engine light in stock modes (for dealer services and such).

Do you think the ECU is compensating based on these codes and that is why I’m noticing these problems?

In any event, I think my next step will be removing the spacers especially with all this TD1 talk no point in trying to avoid the ECU tune conversation as once the car is connected they (Audi) will know I’m tuned.

I am interested in logging via Vagcom to validate my assumptions. Does anyone know the field numbers I would be logging?

Oh yeah, Thanks again Sak and beemercer for your input! Very helpful!

#13

has anyone thought about flashing back to stock before going for service?

I don’t mean the fake stock mode…I mean actually getting the ECU flashed at a dealer back to stock and having the flash counter reset. How would they know you were tuned in that situation?

I was discussing this with someone from JHM and he seemed to think the concern over TD1 might be overblown…that it might be ‘beatable’.

Of course having to go to a dealer with a busted down car won’t be so useful, but if you could flash load a stock file on your car yourself (i.e. the way JHM does it with their S5 and RS4 customers using a cable they provide, and a connection to their server) it would be a potential way to avoid TD1. Just load her up before you go to the dealer…get the work done…then flash back to JHM 93 or whatever once you’re done.

#14

Wouldn’t a dealer be curious about the flash counter being reset?

#15

helps to know people on the inside lol, not like I’ll ever be buying an under warranty audi

interesting that the tune doesnt actually do a cat delete, do you fail cat readiness?

#16

how would they know it was reset? (if you set the ‘last reset’ or ‘last flash’ marker to something entirely normal/plausible)

#17

There was some discussion of this on AZ. I know one person locally who got flashed back to stock and is going in for service soon. I’m sure there are others, we’ll know soon. It seems like the best shot at avoiding TD1 flag thus far.

The problem (as I understand it) is that once you get flashed back to true stock, all the original encryptions are back in place, so getting your tune back requires pulling the ECU and cracking it open again. Aside from the labor involved, after doing that a few times the seals will probably look as sloppy as a two dolla ho.

#18

that one REVO guy who had his engine torched ended up getting flashed back to stock, went in, got checked out, and was (last I heard) getting a new engine, covered by warranty.

Haven’t seen that guy discussed much yet…wonder if it’s making REVO tuned guys nervous?

#19

wait wait wait… a revo car blew up??? a b8 s4 revo car? Where is this information?

Given the aggressive timing they are running along with a few other choices they have made in their tune I will say it again, it’s going to be an interesting summer… :o

#20

yes, fried a cylinder wall or something. Not sure on alll the details. Someone emailed it to me…I’ll dig up the link.

edit: found

http://forums.audiworld.com/showthread.php?t=2824645

again…very surprised this hasn’t been discussed more