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Model specific boards => Golf mk4 => Topic started by: dr.gonzo on 16 January 2009, 05:25

Title: possible causes? O2 sensor low voltage ie running lean!
Post by: dr.gonzo on 16 January 2009, 05:25

Not realy a golf, its wor lass's beetle but its an AQY 2litre engine same as the mk4gti only the rest of it looks stupid :sick:
anywho, im getting low voltage errors at bank1 o2sensor!
the sensor is brand new so i was wondering what other possible faults could be causing this?
im thinking maf?or vaccuum leek or something? id assume id get a fault code for a vacuumleak pinpointing it tho or a maf error?
thing is the sensor was solid and threads were stripped so i couldnt get it out so i had to remove the whole intake system and manifold to extract it and recut the threads before putting it all back.
is it possible i need to clean the throttle body? could this trigger a low voltage?
ok now im gona get slatered here!
errrrrrrrrrrr its a cheap sensor and i had to extend it to make it reach so it has 2 joins(soldered tho) in it aswel.
im going to get a proper vw one  but i was just curious of other things to check before i do?
cheers!

Title: Re: possible causes? O2 sensor low voltage ie running lean!
Post by: Rhyso on 16 January 2009, 07:57

if you're getting low voltage errors have you checked the wiring going into the O2 sensor

sadly a lot of people replace the sensor thinking its the problem but 7/10 its the actual wiring that has broken down

Title: Re: possible causes? O2 sensor low voltage ie running lean!
Post by: dr.gonzo on 16 January 2009, 08:35

yeah seems ok but im gona clean all the contacts to be sure.
one of the first things i done was go over the wiring.
well i say one of the first things, wot i mean is i forgot to plug the  ecu wiring back in and got a sh!t load of error codes and the car was like a bag o hammers, being out of sight i hadnt realised so was tearing me hair out wondering what the hell was wrong.
im not sure but its ringing a bell that i got a no activity code at one point which points right at the wiring but im not 100% as id erased the code before i checked the book and couldnt for sure remember what it was for definate.
im hoping i get that code again, then i know for sure its the wiring somewhere.
cheers

Title: Re: possible causes? O2 sensor low voltage ie running lean!
Post by: dr.gonzo on 16 January 2009, 17:21

i think ive sussed it!
ive put in a zirconia but i think it needs planar sensor!!!!!
makes sense cos the light comes on within 2 mins of being cold BUT if the car is warmed thoroughly it seems to stay off untill its stood a while, then back on again from cold!