Mike Sigmond

Thanks for the reminder

In my manual an 04 model has these color wires:

Bank 1 Front sensor before cat
Tan/white
Purple/white
&
Blue
Pink

Bank 2 After cat sensor
tan
purple
&
blue
white

I believe the tan & purple ones are the signal ones & the blue and pink solid ones are the heater.

Please let a ASE tech or experienced member here verify this first, If I have it backwards and the tan & purples are the heater you will fry it.

I hope this helps understand it

Here is an example of how it works...

516rider

thanks. yea if someone else could verify that. that would be awsome. you guys sure know your stuff. i am really thankful for joining this fourm

wffokker

i thought the wires with white were heater but i am starting to doubt now, so like mentioned before have somebody verify, or use volt meter to find out.

Mike Sigmond

Well the pink & blue ones go straight to a fuse & ground in the diagram which makes me feel they are power for the heater, the tan & purple ones go the computer harness, upstream & downstream signal. The stripes just are for the bank 1 sensors.

Just my 2 cents about it.

516rider

ifi use a volt meter than on the tan and purple shouldnt come on if the key isnt in right? and the others will be on.

Mike Sigmond

I am not sure. I think the engine needs to be running for them to power up. In cold start they will be in open loop for a minute or so until the 02's heat up, once they close they begin sending a signal.

516rider

ok i will try it. should i go ahead and tap into the purple one. or just wait to see if i get a reading with the volt meter

Mike Sigmond

If it were me I would tap the wires and look with a voltmeter first, I assume the heater wire will carry 12-14 volts from the fuse panel and the signal wires should have a 0-10 or 0-5 volt variance, at least that is how computer signals work on most applications I have worked on.

516rider

ok that works. and if both tan and purple wires read the same which one will be the best wire to tap into

Mike Sigmond

My guess is the downstream will not change, maybe 5 or 10 volts solid, the upstream is the signal back that varies fom 0 to whatever volts. maybe I have it backward but if both these are the signal wires just tap the one that fluxuates when the motor is running and being driven. Make some lead wires long enough to have the meter in the vehicle when verifying you have the right wire.