"Limp Mode" Question on B8.5 S4

[JBA87]

I was driving hard today (racing) and as I was shifting gears from 2nd or 3rd may car went into "limp mode." The tire pressure malfunction light also came on with a check engine light. Car would not accelerate as normal. I immediately took the car to the gas station, turned her off, filled her up slightly, and turned her back on: all back to normal. Why does the car go into this limp like state? Is it a result of poor driving? Reaching too high on redline? What are the issues? Any feedback would be greatly appreciated. I have a 6mt apr chip, awe resonated, uSP intake..thanks

[SwankPeRFection]

Did you check the tire pressure in each tire to make sure they're equal and then reset your TPMS memory along with everything else you checked?

Really without a VACCOM you won't be able to pull the codes and see for sure what it was.

[JBA87]

I didn't the check the tire pressure, but it wasn't really a tire pressure issue. It was definitely an engine issues that just triggered the TPMS light. There was also some suspension icon that came up that had an image of the suspension being misaligned or something to that effect.

How much are the VAGCOMS?

[LYKUNO]

I saw this on a search for limp mode issue on an A6 ...



so after much research I found that my car is in limp mode or safe mode what could cause this I vaged it and this is what i got

trying to fix the problem /patch before the snow fall any ideas guys???


Address 02 -------------------------------------------------------
Controller: 4B0 927 156 DJ
Component: AG5 01V 2.7l5VT USA 1717
Coding: 00002
Shop #: WSC 00000
2 Faults Found:
17114 - Incorrect Gear Ratio
P0730 - 35-00 - -
17118 - Gear 4 Incorrect Ratio
P0734 - 35-00 - -

Address 03 -------------------------------------------------------
Controller: 8D0 907 389 E
Component: ABS/ESP allrad D56
Coding: 06397
Shop #: WSC 02325
2 Faults Found:
00283 - Front Left ABS Wheel Speed Sensor (G47)
27-10 - Implausible Signal - Intermittent
00285 - ABS Wheel Speed Sensor: Front Right (G45)
27-10 - Implausible Signal - Intermittent

Address 08 -------------------------------------------------------
Controller: 4B0 820 043 AH
Coding: 00160
Shop #: WSC 02325
Note: Excessive Comm Errors

Skipping Address 15-Airbags

Address 16 -------------------------------------------------------
Controller: 4B0 907 487 D
Component: Lenkradelektronik D03
Coding: 00102
Shop #: WSC 65535
No fault code found.


Since the wheel speed sensors were at least partially implicated with this A6 going into limp mode, perhaps the tire pressures were involved in your case. I recently had one tire that was 2lbs lower than the others (brand new tires just installed and I hadn't set the TPMS reset completely), and suddenly got two TPMS icons displayed on the dash (a cross section of a tire icon with an exclamation mark inside it - one on the tach and one on the mmi display) after the car had been driven for a couple of hours. The only other icon I could see at startup that might be what you were looking at is the one of a car with skid marks behind it. Anyway, the first thing I'd do is check and make sure all tire pressures are properly set and then set the TPMS memory. Don't forget after clicking "Store Now" that the next screen displayed has a default of "Cancel" selected, so be sure to select the "Confirm" option before exiting.

[Okan509]

this exact thing happen to me between shifts... I restarted the car and reset the TPMS and it was all fine.

But I have no idea why.. the shift was smooth, but exactly like you said it wasn't accelerating as normal, like the blower was off or something...

also driving hard..

[shonseb]

Just a thought but... transmission overheating?

[JBA87]

Its possible that its a transmission overheating issue, but this begets the question: does audi implement a 'limp mode' safeguard when the car exhibits the symptoms of a transmission overheating? Moreover, why was the transmission overheating in the first place?

It seems like whatever the issue was that the car went into some de-tuned mode, almost as if the car had been completely de-powered (like if cylinders were disabled). You step on the accelerator and the car would not accelerate anywhere remotely close to normal acceleration.

[JBA87]

So I pulled out the instruction manual. The suspension light was a sports differential malfunction. One of the reasons that this light comes on is transmission overheating from sporty driving. I don't see anything in the manual regarding the limp mode. The other indicator lights that came on included the EPC light and the TPMS malfunction light. I wonder why the transmission got hot so quickly. I only accelerated hard for a few miles? Is there a modification I can install that will help with transmission temperature?

[gendry]

Where you doing many hard turns with heavy acceleration during the turn? If not, the SD should not have been transferring torque and not heating up if it is working properly.


So I pulled out the instruction manual. The suspension light was a sports differential malfunction. One of the reasons that this light comes on is transmission overheating from sporty driving. I don't see anything in the manual regarding the limp mode. The other indicator lights that came on included the EPC light and the TPMS malfunction light. I wonder why the transmission got hot so quickly. I only accelerated hard for a few miles? Is there a modification I can install that will help with transmission temperature?

[JBA87]

No I was in a straight line shifting into 3rd when all of a sudden the car went "ding" , the malfunction lights came
On, and the car entered a limp mode with significantly diminished power and acceleration. Pushing the accelerator all the way to the floor would barely accelearate the car. The car would drive though.

[Arin@APR]

No engine fault codes?

[shonseb]

Arin working on a Sunday?

[Arin@APR]

Sundays, holidays, births, weddings, early in the morning... Our competition doesn't. That's why you choose us.

[JBA87]

Arin

I don't know. Don't have a vagcom. All I know is that the sport diff, EPC,
And tire pressure malfunction light came on after a shifting into 3rd in a race. The car then went into the limp mode that I hav described with significantly diminished acceleration. As soon as I restarted vehicle everything was fine. FYI this happened to my car before when i first purchasd, my engine blew, and Audi replaces the engine. Yesterday was first time it happened since engine replacement and my apr tune.

[LYKUNO]

Sundays, holidays, births, weddings, early in the morning... Our competition doesn't. That's why you choose us.

Does this mean the honeymoon is over?