# o2 sensor fuse location??



## ballergti (Nov 17, 2010)

throwing some p0031 code. o2 sensor bank one sensor one. just replaced sensor still have code need to know where fuse is. also throwing p0102 and its a MAF sensor code and i replace Maf sensor still have the code. Im hoping this fuse fixes it.


----------



## ballergti (Nov 17, 2010)

Come on. Is there a relay the o2 sensor are connected too?


----------



## groggory (Apr 21, 2003)

I believe the o2 heater is run through the 'fuel pump' relay


----------



## ballergti (Nov 17, 2010)

groggory said:


> I believe the o2 heater is run through the 'fuel pump' relay


Thanks for the help:thumbup:
If its not this relay what's your insight on what's throwing these codes?


----------



## groggory (Apr 21, 2003)

Do this for a test...

Go under the car and unplug the front oxygen sensor from the harness.

Key the ignition on

Using a voltmeter, set it to the 20V range.

Test the voltage between pin 3 (blue/red) and pin 4 (white)

The voltage should read somewhere around 12V. Post up what you find.


----------



## ballergti (Nov 17, 2010)

groggory said:


> Do this for a test...
> 
> Go under the car and unplug the front oxygen sensor from the harness.
> 
> ...


 It's only putting out 2.20v so we know this is the problem but how do I fix it?


----------



## groggory (Apr 21, 2003)

I bet it's a bad relay










Hypothesis... No testing to back this up 

Pull relay 409

Key off

Check voltage from ground to the socket pin 2. I bet there is 12v

Now key on. I bet the voltage is STILl 12v

Ok. Now key off. Check voltage on socket pin 8. I bet the voltage is around 0v, give or take

Now key on. I bet the voltage of socket pin 8 is the 2.whatever voltage you saw earlier .

 

Let me know what you find


----------



## ballergti (Nov 17, 2010)

Okay so pin 2 is 12v with key on and off and pin 8 is 0 with key off and 0.02 with key on.


----------



## groggory (Apr 21, 2003)

Lol @ me. Of course pin 8 isnt hot! The relay's not connected!

Lol

Go get a new relay. There's your problem.

Look at the pic i posted and you'll understand


----------



## ballergti (Nov 17, 2010)

Okay I'll get a new one and post back if it works. Thanks a lot for help.


----------



## ballergti (Nov 17, 2010)

So I replaced the relay with my girlfriends and nothing. When I unplug it and plug it in her car it goes "click""duuuuuuuuuu. When I plug it in mine nothing. I think it's a connection even before the relay.


----------



## ballergti (Nov 17, 2010)

Okay so I ordered a new MAF and still no luck and my asr light is still on and won't turn off.


----------



## ballergti (Nov 17, 2010)

Anyone? I keep throwing money at this car and can't get it going smooth. Why am I throwing these 2 codes and asr light??


----------



## groggory (Apr 21, 2003)

ballergti said:


> Okay so I ordered a new MAF and still no luck and my asr light is still on and won't turn off.


Totally unnecessary. You still haven't figured out your o2 sensor heater circuit problem.

Figure out why your o2 heater isn't turning on.


----------



## groggory (Apr 21, 2003)

Go pop the fuel pump relay off on your gf's car. 

Key off. Measure and record all pins voltages in the relay socket with reference to ground

Key on. Do the same

Then repeat on your car

Post the results


----------



## ballergti (Nov 17, 2010)

groggory said:


> Go pop the fuel pump relay off on your gf's car.
> 
> Key off. Measure and record all pins voltages in the relay socket with reference to ground
> 
> ...


 It's probably gonna be the same because the car runs and still throws the same codes. What else could cause these codes?


----------



## groggory (Apr 21, 2003)

ballergti said:


> It's probably gonna be the same because the car runs and still throws the same codes. What else could cause these codes?





> It's only putting out 2.20v so we know this is the problem but how do I fix it?


 We still haven't resolved why you measured 2.2V at the oxygen sensor heater pin. 

That's why I asked you to check that relay socket...unless you have a better idea on why you were only getting 2.2V.


----------



## Rac_337 (Sep 24, 2004)

groggory said:


> We still haven't resolved why you measured 2.2V at the oxygen sensor heater pin.
> 
> That's why I asked you to check that relay socket...unless you have a better idea on why you were only getting 2.2V.


 are you sure he measured the correct pin? I thought there was a pin down there somewhere that outputs 2.2v


----------



## groggory (Apr 21, 2003)

Rac_337 said:


> are you sure he measured the correct pin? I thought there was a pin down there somewhere that outputs 2.2v


 I'm not sure he measured the right pin. However, here's what I told him to do.... 



> Do this for a test...
> 
> Go under the car and unplug the front oxygen sensor from the harness.
> 
> ...


----------



## ballergti (Nov 17, 2010)

groggory said:


> I'm not sure he measured the right pin. However, here's what I told him to do....


 I went under the car and did the voltage check and yup 2 middle pins putting out 2.4v now. An this is with a different 409 relay. So it's not the relay.


----------



## groggory (Apr 21, 2003)

ballergti said:


> I went under the car and did the voltage check and yup 2 middle pins putting out 2.4v now. An this is with a different 409 relay. So it's not the relay.


 The positive wire goes to the 409 relay. 

The relay is good. 

So that means that one of the pins in the relay socket is bad. 

I don't know which one. 

I suggest you do the relay socket test like I asked earlier 



> Go pop the fuel pump relay off on your gf's car.
> 
> Key off. Measure and record all pins voltages in the relay socket with reference to ground
> 
> ...


----------



## ballergti (Nov 17, 2010)

groggory said:


> The positive wire goes to the 409 relay.
> 
> The relay is good.
> 
> ...


 Hold on so I just took the relay out and tested voltage between the two big middle pins again and I'm getting 12 volts now with the key on on. This Is just crazy.


----------



## groggory (Apr 21, 2003)

ballergti said:


> Hold on so I just took the relay out and tested voltage between the two big middle pins again and I'm getting 12 volts now with the key on on. This Is just crazy.


 Electronics is all about the details. 

Make a new post. 

Post up all your information and detailed observations. Let's see if we can make heads and tails of this whole hoopla.


----------



## ballergti (Nov 17, 2010)

What about my p0102 code. Maybe that's what's causing the o2 sensor problem. I bought a brand new MAF but if the the car is running I can unplug it and nothing changes so that's not getting power either? I'm so lost this sucks.


----------



## groggory (Apr 21, 2003)

ballergti said:


> What about my p0102 code. Maybe that's what's causing the o2 sensor problem. I bought a brand new MAF but if the the car is running I can unplug it and nothing changes so that's not getting power either? I'm so lost this sucks.


 Exactly. 

You have lots of individual symptoms. 

I'm just asking you to take all your symptoms, rewrite them into a clear, detailed, exact, intelligible post, and then we'll reanalyze based on all of your diagnostics. 

From there we can determine the next step to take in solving this.


----------



## nitroTT (Jun 20, 2015)

Hi have you figured out what was wrong with your car I am having the same symptoms. Thanks

Sent from my SPH-L720 using Tapatalk


----------



## ballergti (Nov 17, 2010)

Pretty sure it was just fuse 43 bruh. This was also 3 years ago but I did somehow fix it but try checking fuse 43.


----------



## nitroTT (Jun 20, 2015)

Yeah I just checked the fuses and that was my problem. so pissed that I bought a new maf sensor before I checked 

Sent from my SPH-L720 using Tapatalk


----------



## vtraudt (Mar 1, 2010)

What circuit is fuse 43 on your car?


----------



## KiDGiB (Jan 28, 2013)

vtraudt said:


> What circuit is fuse 43 on your car?


http://forums.vwvortex.com/showthread.php?951306


----------

