Help with strange fault code...

[derek.kritz]

So, here is the quick backstory...last week driving normally. Car goes into limp mode. Epc light comes on. Tcu light comes on says transmission malfunction, parking brake malfunction. Pull over. Run codes off my carista app. Got the 01315, and a couple other strange ones I could not remember at the time. I should have taken a screen shot but was pretty pissed, so I forgot. Was thinking Mechatronics or wire harness going bad. Anyway, cleared codes. Car started right up. No hiccups at all. No prior trani issues to this. No hard shifts. Nothing. Car is a 2010 dsg EPL e85 stage 2 with EPL tcu tune btw. And the whole trani was replaced by Audi at 35k. 52k on the clock now. Week goes by. No other issues. Thinking maybe a fluke. One time thing.
Fast forward tonight. Driving and limp mode again. This time just epc came on. No tcu malfunction. Pulled over and scanned car. Got this...

I remember that "fuel composition" code from the first time. Cleared codes again. Started up like nothing. Anyone have any ideas? Could it be my e85 was below 70% alchol? I usually test it but haven't the last couple times. Is there a fuel sensor going bad? Could it be an issue with the tune? I tried searching and couldn't find anything on this code. Any insight would be appreciated. I already emailed EPL and gonna see what they say.



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[jygesq]

What condition is your battery in?

[BoostEasy]

What condition is your battery in?

+1.

If you get a lot of odd codes it sounds like low-voltage or the battery cutting in and out.

If it's happening while driving, that's a little more concerning. Maybe throw a voltmeter across the battery terminals with the engine on & idling and see what the voltage is. You may be able to pull it with Carista app too.

You should be getting 13.5V or better with the car running at idle I would think. If it's lower like 12-12.5, it could either be the battery or alternator (brushes) going south.

[derek.kritz]

+1.

If you get a lot of odd codes it sounds like low-voltage or the battery cutting in and out.

If it's happening while driving, that's a little more concerning. Maybe throw a voltmeter across the battery terminals with the engine on & idling and see what the voltage is. You may be able to pull it with Carista app too.

You should be getting 13.5V or better with the car running at idle I would think. If it's lower like 12-12.5, it could either be the battery or alternator (brushes) going south.

Got it. Will do that today. Thanks guys!!

[derek.kritz]

So, got a reading of 13.5-13.7 on the battery when car was started. 12.5-12.8 when car off. Battery seems to be in good health. Any other ideas??
Car ran fine today. Filled up with e85 yesterday after the episode that measured 87% ethanol. The car seemed to run better today. Snappier. Maybe the fuel composition code was thrown cause of bad e85 in the tank?? Dunno??


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[skiptowncat]

Maybe the fuel trims have reached a critical limit due to running e85?

[BoostEasy]

So, got a reading of 13.5-13.7 on the battery when car was started. 12.5-12.8 when car off. Battery seems to be in good health. Any other ideas??
Car ran fine today. Filled up with e85 yesterday after the episode that measured 87% ethanol. The car seemed to run better today. Snappier. Maybe the fuel composition code was thrown cause of bad e85 in the tank?? Dunno??


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As skiptowncat said, check your long term and short term fuel trims to make sure neither is maxing re the fuel comp code . Ideally using Vag-com. I'm not sure how reliable the OBD is going to report it. Probably ok but I'd like to check it with vag-com to be sure. I don't know the code offhand but I know I've seen it in there.

If you don't have vag-com and are running an E85 tune, I'd suggest picking it up.

[derek.kritz]

As skiptowncat said, check your long term and short term fuel trims to make sure neither is maxing re the fuel comp code . Ideally using Vag-com. I'm not sure how reliable the OBD is going to report it. Probably ok but I'd like to check it with vag-com to be sure. I don't know the code offhand but I know I've seen it in there.

If you don't have vag-com and are running an E85 tune, I'd suggest picking it up.

Cool. I have a vag at my disposal, not mine but I can use it anytime. Could you shoot me the parameter numbers if you got a sec that i should log for fuel? Thanks!!

[BoostEasy]

Cool. I have a vag at my disposal, not mine but I can use it anytime. Could you shoot me the parameter numbers if you got a sec that i should log for fuel? Thanks!!

I'll pull out my tablet and take a look tonight.

[derek.kritz]

I'll pull out my tablet and take a look tonight.