johnny--2k

I know this has been covered to death, but I didn't find anything related to what I have encountered.

Car is a 2009 with 21K miles on it now. Yesterday, I got a CEL after a WOT 1-2 run and had the code pulled as P0171. Made a few stops, lots of driving last night afterwards, and by the time I was headed home the CEL went off, so I figured it was a fluke.

Today, only made one trip with a 2 hour stop in the middle, and on my way home, did another WOT run from mid 1st into 2nd. CEL came on again, guessing it's the same code.

I have the charcoal delete for a few months now, and eurocharged V5 tune for over a month, which I let them know that the only other mod was the CD before getting the tune and loading it. I've had the tune for a while now, and last week put over 600 miles on the car driving from Dallas to San Antonio and back, with multiple WOT runs both city and highway with no issues until yesterday.

Any input on what this could be? I'm guessing it's not an intake manifold/gasket issue since it is intermittent, but possibly the pre-cat o2 sensor on Bank 1, since that was the code. What could be causing this to go off only with WOT pulls?

The car is CPO, so I'll take it in and have it dealt with, just frustrating and not something I want to have to worry about. It makes driving the car not as much fun if I have to worry about lean conditions and CEL's constantly popping up.

Thanks in advance!

johnny--2k

Also, car seems to be driving fine, no stumbles or stutters, and no other anomaly's.

bhamg

My P0171 code recently popped up after some WOT runs also. Today I got around to putting the propane torch around the manifold but there was no effect on the idle, so for the moment I am ruling a leak out. What did your dealer come up with?

Petakii63

Had the same problem with mine 2 weeks ago. Started my car CEL. Turned it off CEL gone. WOT a couple times and boom instant loss of power and CEL again. Mine was an intake manifold leak. Basically, the inside of my intake had warped. Got the car back and drives smooth and pulls like a freight train. How does the car idle? Mine was idling like ****.

bhamg

Idle is normal, holds stable at about 550rpm.

HBC350

Disturbing if accurate.

johnny--2k

Weird... my CEL just came on again today. Totally random, was not driving hard as I was in traffic the entire way back to my hotel, and I parked and was on the phone for about 20 minutes, looked down and noticed CEL was on. Pulled code and P0171 again. Car idles and drives fine.

No clue what's going on. Eurocharged said it may have been because of my charcoal filters being removed, put them back in a few months ago and the car has been fine since until today. I am down in Houston though, and may have some time Thursday so if it's still on, I will be making a pitstop at Eurocharged's shop and have them see if something is off slightly in the Tune causing it to go off randomly.

bhamg

I was at (my other) dealer today for a trans fluid change which was put off until Fri because my car was too hot to be worked on and couldn't be returned same-day. FWIW I gather from talking to three area dealers that despite the WIS they don't drain the torque converter as part of the normal fluid change and charge extra for it. None of the three mentioned that either until I asked. I don't mind paying the extra charge but IMO it's a pretty crappy practice to ignore the WIS-recommended procedure. Forewarned is forearmed.

johnny - I'll be talking to RENNtech later this week about this issue. Also, I'll pick my SA's brain...he used to be a M-B tech so he may have some useful feedback too.

Petakii63

It's not the removal of the charcoals. Or the tune. It may have been how the airbox was re-installed. Any hesitation while driving or Accelration? Are you running paper filters or hi flow? I'm betting you have leak... Since P0171 is fuel mixture code.

johnny--2k

Cool, I will update if I can.

The only out of the ordinary things in the past two weeks was a Low Coolant warning once, but turned off and restarted and never came back, and a check oil level a few days ago. Topped off with about half a quart and no issues otherwise. I am about 1200 miles before Service A is due, scheduled for this friday but I'll see if it goes away before then.

AMG893

I recently did my own tranny fluid flush, and i drained the torque converter. More oil in there than in the pan.

Its a must to do. No point in draining half the fluid. Pointless. And what a shame that MB charged extra to do a job PROPERLY.

nallishaw

my car was doing this, the dealer said it was my PCV valve, I didn't really believe it, however they replaced it and the CEL never came back on

johnny--2k

Well, mine went away again today, after only a few short drives. I already had the Purge Valve replaced, but you are saying the PCV Valve could cause this intermittent CEL to pop up?

OlegKouz

I have the Weistec oil air/separator and noticed that since installing and after I do a few WOTs the code will pop up, but after a little bit the code will go off and not show up when running for the soft code either..I think it's not a big deal as I have had this going on for about 5k miles with no issues (nearing 40k miles now, been DDing her since day 1 lol) and have gotten her serviced during that time span at my indy shop

bhamg

Mine too! I was on the 3rd drive cycle and it was do or die for CEL. After 40 miles on the freeway it was still on so I turned off and took the car on a canyon run...little traffic meant I could keep it in D2 (high RPMs) and pretty much hammer the car. Amazingly, after about 3 or 4 minutes I happened to look down and the CEL had been extinguished. The very same conditions that switched it on had turned it off, go figure. I spoke to RENNtech today also. They'll let me know tomorrow what their thoughts are.

johnny--2k

So took my car in today for the A Service. Told my SA about the CEL, called me and told me they need the car two more hours, found a small leak in the Intake Manifold Gaskets. Replaced both under CPO, just picked it up about half hour ago!

w204nyc

What kind of reading devices are you guys using? I'm in need
Of one

rentzington

Curious how common it is for the intake gasket leaks, seems like it would at least be a fairly inexpensive fix relatively speaking anyway

johnny--2k

I just had the code pulled at an AutoZone. The dealership has more detailed tools that can better pinpoint the problems I'm sure.

bhamg

So I talked with RENNtech yesterday. It was interesting and I learned a few things but there was nothing definitive about the codes. Everything is good with the car and I've decided to replace the intake manifold bolts, one at a time while leaving the OE gasket in place in the hopes of eliminating the possibility of future leaks. I'll use Blue Loctite in addition to the torque to yield procedure.

Also I had the trans fluid changed today. In the past 5k miles I've experienced some unusual hard shifts - even a few significant jolts - so based on what some here posted I had it replaced. Surprisingly the shifts seem smoother. I should find out if the hard shifts are a thing of the past within the next thousand miles..

johnny--2k

nice! I'm only at 26K miles, so another 10K miles and then I have the 40K service which is the tranny flush.

rentzington

That's the one I have coming in a few months, that one is a real wallet buster

johnny--2k

Pre-Paid Maintenance FTW!

bhamg

Most here seem to use this:
https://play.google.com/store/apps/d...l.torque&hl=en

I use this:


The cheap $20ish devices you see on Amazon usually don't work on this car.

Johnny912

Hello all, I've been having this problem for about a movth. Since I got my v5 (by the way car is also a 2009), Charlcoals, k&n filter and both cat n res delete on mine. And after 40-80 miles of hard driving or regular driving the cel would come on even after I reset these codes.

Now I didn't check for any leaks or bad sensors cause exactly like you stated....the car ran great. Only thing I could think of was that the New tune and the abnormal cold temperatures was the problem....well I was wrong but all I could think of....
After about 30 emails with eurocharged, and 4 different tunes later we were puzzled.

Note-sorry if this was already brought up but I didntnt read through the whole thing.

But I finally received a tune call v5fuel....now I don't know what different mapping was used but I drove 400 miles in the t k and nothing.....wot pulls, regular under 2500rpm shifts, and even some racing.
Well I was told that some older c63 have an outdated software installed the factory. And the by tune will act a little funky. Also told I May have to take my ar to the dealer to have the install the newest software. Gona do some more drivmore and see what happens but so far this New tune hasn't thrown a code. Hope this helps