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Old 02-16-2018, 02:41 PM   #1
sth36
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Join Date: Jun 2016
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Location: Harrisburg, PA
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2016 WRX, Stg 2, FF
Ice Silver

Default COBB1 Ethanol Sensor Low Voltage Input

Currently dealing with this code. I drove to work this morning with no problems, car has been running flawlessly. This afternoon I went out to grab lunch, cranked the car, and boom--there is the CEL code.

Has anyone dealt with this? I spoke with Cobb briefly who requested a data log which I cannot get them at this moment. They gave me a couple items to look for:
1. Ethanol final is locked in and not changing
2. Ethanol Raw is 0.0
3. TGV Left is .10-.12
4. TGV Right is 0.0

Full mods:
FBO except for an intercooler and the intake
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Old 02-16-2018, 02:49 PM   #2
GlarryHoodDIT
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Sounds like lose connection or a cut wire.
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Old 02-16-2018, 02:56 PM   #3
sth36
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Quote:
Originally Posted by GlarryHoodDIT View Post
Sounds like lose connection or a cut wire.
I checked all the connections I could access from the engine bay and they were all okay. The only one I haven't been able to check is the one on the O2 sensor. I'll have a look when I get home tonight.

Thanks for the reply!
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Old 02-16-2018, 04:04 PM   #4
idiosyncrisia
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I've had issues before with a cold (also the temps were cold) start and CEL in regards to voltage on a sensor. Cannot remember which one. I cleared the code (also reflashed my map for a different reason) and it has yet to come back. I just attributed it to a poor initial voltage or something. If it does come back, then I will start worrying.
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Old 02-17-2018, 07:23 AM   #5
ericdet
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2018 Civic Type R
2008 N54 335i

Default

Quote:
Originally Posted by sth36 View Post
Currently dealing with this code. I drove to work this morning with no problems, car has been running flawlessly. This afternoon I went out to grab lunch, cranked the car, and boom--there is the CEL code.

Has anyone dealt with this? I spoke with Cobb briefly who requested a data log which I cannot get them at this moment. They gave me a couple items to look for:
1. Ethanol final is locked in and not changing
2. Ethanol Raw is 0.0
3. TGV Left is .10-.12
4. TGV Right is 0.0

Full mods:
FBO except for an intercooler and the intake
What are you getting for those 4 values? Just put them up on the AP screen. Loose connection or outright sensor failure. The Continental sensors are pretty reliable but it is a sensor after all. Pretty much they're wanting to see if the sensor isn't working or if the whole system isn't working. If you have no TGV inputs the whole system isn't working. If the first is locked but the second is 0 then it's probably the sensor.
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Old 02-17-2018, 03:19 PM   #6
13wrecks
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DGM

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Had this code last week. Checked connections. Ran ethanol out, filled up with 93 and reset code. Didn't come back so added ethanol. been good so far. That tgv voltage is indicative of issue with sensor
https://cobbtuning.atlassian.net/wiki/plugins/servlet/mobile?contentId=75530476#content/view/75530476
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Old 02-20-2018, 11:03 AM   #7
sth36
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Just a quick update since I was away the weekend. Friday afternoon I checked and rechecked all connections but nothing changed. I left for the weekend, the car sat in a nice warm garage, and when I got back in on Monday night, the issue was gone.

Cobb mentioned that it could have been that the fuel sensor was clogged. My thinking is that the fuel acted as a solvent and dissolved whatever it was that was clogging it.

What I can't explain is how the reading on my left TGV went from .12V to 2.20V. Perhaps there was moisture in the connection that evaporated out while it sat?
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Old 02-20-2018, 11:13 AM   #8
13wrecks
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DGM

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Did the code clear on its own or did you reset?

I reset and voltage went from .1 to 1.xx for awhile and is now 2.xx

Maybe a moisture problem like you said. I know it was wet and rainy when my code first tripped
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Old 02-20-2018, 12:54 PM   #9
ericdet
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I hate things that go away on their own.
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Old 02-21-2018, 11:26 AM   #10
sth36
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Ice Silver

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I had to actually reflash the map. For some reason I couldn't just clear the code on my AP. I tried twice and then tried to reflash and that fixed it.

I literally got home early on Monday to try to unclog the sensor and was SHOCKED when I started the car and saw the sensor working.

Yeah Eric, it sure did make me mad haha
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Old 02-26-2018, 10:19 AM   #11
sth36
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Ice Silver

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Well it came back this weekend. Exact same symptoms, exact same code. Seems to come when I leave the car out when it's wet. Kept it in the garage last night and woke up and it reads normal voltage.

Any ideas?
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Old 02-26-2018, 01:02 PM   #12
ericdet
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2008 N54 335i

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Quote:
Originally Posted by sth36 View Post
Well it came back this weekend. Exact same symptoms, exact same code. Seems to come when I leave the car out when it's wet. Kept it in the garage last night and woke up and it reads normal voltage.

Any ideas?
Physically pull and inspect all of the connections.
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Old 02-26-2018, 01:07 PM   #13
gn4rwhals
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Any excess water in the engine bay after it rains?
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Old 02-26-2018, 01:52 PM   #14
sth36
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Ice Silver

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Unplugged and re-plugged all connections with no change. There is not any excess water in the engine bay.
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Old 03-05-2018, 10:13 AM   #15
13wrecks
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DGM

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Popped this code over the weekend for the second time, 1/2 hr into a 4 hour road trip. Good times. Was raining/freezing rain. Looking at replacing the sensor now. All other connections look good. Hadn't had an issue for the last 3 weeks or so after the initial reset

Did you get any resolution with this yet? Are your tgvs deleted?
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Old 03-05-2018, 10:46 AM   #16
sth36
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Ice Silver

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It definelty is weather related. I was able to clear the code but the first day I parked it outside when it was raining it popped up again. I reached out to Cobb and they sent me another wiring harness (the "brain" as they call it). I am going to try to get it installed this week if I can find the time and see if it helps.

And yes, my TGVs are deleted. Who is your tuner?
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Old 03-05-2018, 11:02 AM   #17
13wrecks
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DGM

Default

That's is very interesting. I reached out to Cobb and they sent be a new sensor. No new harnesses......
Doesn't throw a code every time I get rain so was thinking maybe it was a coincidence?

My TGVS are deleted as well. Was maybe thinking the unused connector was not properly sealed up.

I'm protuned by Bren.
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Old 03-05-2018, 11:19 AM   #18
sth36
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2016 WRX, Stg 2, FF
Ice Silver

Default

They suggested it was the ethanol sensor at first, but when I could predict the voltage failing based on weather, they agreed it was likely electrical. So after you replaced the sensor you still got the code? Perhaps it is the wiring then and I'm in luck!
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Old 03-05-2018, 12:59 PM   #19
13wrecks
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DGM

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Haven't installed the new sensor yet. After clearing the code the initial time I had been issue free for weeks. Gonna have to install the new one now and plan and clearing and greasing all connectors with dielectric grease. Lmk how you make out. We each have one piece of the puzzle hah.
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Old 03-05-2018, 05:20 PM   #20
blackote
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CBS

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I had this same issue when I installed my kit. I contacted COBB and they actually sent me a new kit out to replace it with. I decided to take the power plug (connecting to the O2 sensor) and bend the male leads to ensure contact with the female side. Havent had an issue since.
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Old 03-08-2018, 07:29 PM   #21
nickdgraham
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had the same problem.. there's a param your tuner can set.. it's the max time interval that the sensor can not receive power and not throw the code.. .think he increased mine from 30 ms to 50 ms. i could be wrong on the numbers and units, but that fixed it.
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Old 03-12-2018, 04:05 PM   #22
sth36
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Ice Silver

Default

Installed the new wiring harness or the "brain" of the unit as they call it. Took roughly 15 minutes to get it installed cleanly and everything looks to be good now. I used some dielectric grease with each connection to be safe.

At my last refill I did notice that my TGV voltage and my ethanol raw value are directly correlated, meaning that as Ethanol Raw rises, as does TGV voltage. This leads my to believe that the gents at Cobb actually know a thing or two when they said that a bad ethanol sensor could lead to a low voltage reading/CEL. If the code pops up again then we know for certain that it's the ethanol sensor. Time will tell.
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Old 03-13-2018, 09:52 AM   #23
13wrecks
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DGM

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I popped a code again a couple weeks ago. Just got the new sensor installed and still can't get the code to clear. Talking to Cobb to troubleshoot.....
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Old 03-13-2018, 10:37 AM   #24
sth36
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Ice Silver

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Maybe you already tried this, but the first time the CEL popped up and the problem fixed itself, the only way to clear the code was to actually reflash my map.
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Old 03-31-2018, 12:42 AM   #25
sunnyhaibin
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WR Blue

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I am actually encountering the same issue. COBB01 code could pop up anytime (idle at stop light, cruising on highway, WOT, etc). Talked to COBB and they sent me a replacement of the flexfuel sensor (not the harness/module... yet). Bren at BrenTuning installed the replacement sensor. On the dyno around high RPM, he saw a drop of voltage for a split second and then it read fine again. Now the car is reading 0% Ethanol Raw about 30% of the time, Ethanol Final is locked at 10% at all times. One time Ethanol Raw read 100% which startled me. Seems like the replacement flexfuel sensor made the readings worse. Iím going to contact COBB again and ask them to send a replacement of the flexfuel harness and see what happens.
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