72RATCAMARO

i have a dead 02 sensor now and need to know why. how should the wiring be ran in the stock harness?

72RATCAMARO

wow thats really undiscriptive let me rephrase. The sensor is showing 440mv all the time when truck is running. i hate tracing wiring especially thru the rats nest of a fbody harness. but what should i look for color wise etc for the 02 sensors to be ran into the ecu so i can get it fixed without having to replace the harnes. its a ls6 with a firebird ecu in an s10

LS240sx

iTrader: (12)

Well your talking a lot of wiring to trace. Have you checked to see if the O2 sensor is getting power at the sensor? It may be just a bad sensor not wiring. The wiring shares a ground and power in the harness and the other two wires run all the way to the ECU to give the High/Low 02 signal. There could be a break at these split point but Id check the wire for 12V at the sensor before you rip the harness apart.

LS1MCSS

iTrader: (18)

If you will go to the link, there is a diagram for an 01 that will get you all the colors and pin locations. Scroll about 2/3 of the way down the page.

http://home.att.net/~subzero350/

72RATCAMARO

I am pretty mechanically inclined but suck alot at reading wiring diagrams. can someone tell me at which color wire i should have what volatage. which color should be my ground and which wire/s are my heaters that would be awesome

G-Body

iTrader: (4)

Are all 4 sensors doing this or just 1? If its just 1 which one is it? drive/pass and front/back

G-Body

iTrader: (4)

Every sensor should have a pink wire and a black wire
All the pinks should get 12volts
All the blacks are grounds.

72RATCAMARO

its reading driver side front. i only have front two. if when i unplug my connector the pink wire is reading as if its grounded that would be the problem correct? where should the pink wire run to in the ecu? i will just bypass all the chicken scratch wiring and jump itto the ecu if i knew which wires to use.

G-Body

iTrader: (4)

The pink wire does not go to the PCM, it goes to IGN+12V. It goes to a splice in the harness, and then to C105 pin B. If it was truly grounded the pink wire on the passenger side sensor should also read like its grounded and the engine side of the C105 pin B connector should also read as if its grounded. I would also think that it would be popping the engine sensors fuse.

72RATCAMARO

with the ignition switch off it reads ground. i didnt chech with the swith on because i am retarted. so the pink wires splice together and go to the ignition switch. ok. well which wire will be running to the c105b? wouldnt that still mean the pink wire would be the one with the voltage running to teh pcm telling it the mv that the 02 sensor is putting out?

G-Body

iTrader: (4)

Those pink wires at the o2s join together and then run to C105 pin B.

The sensor has 2 signal wires going to the PCM. The purple/white wire goes to pin 69 of the C1 (blue) connector and the tan/white wire goes to pin 29 of the C1 (blue) PCM connector.

72RATCAMARO

so those two wires should be the ones sending my signal to the pcm. so if when i turn the switch on the pink wire should be 12 volts no matter where i test it and the purple and white. and tan and white should vary voltage. correct? and if i am holding the pcm looking at it which location should the connector be in.

LS1MCSS

iTrader: (18)

If you will pull the connectors from the pcm, you can see which one is blue and red. Mark them as C1 and C2 with a sharpie.

G-Body

iTrader: (4)

Yes the pink wire should have 12v all the way along its length. Do Not use a voltmeter to check for voltage on the purple/white or tan/white wires. You can damage the O2 sensor with a analog voltmeter, it is only safe to do with a digital voltmeter that has greater than 10 megaohm impedance. Disconnect the O2 sensor and disconnect the PCM and then take your meter and set it to measure continuity/resistance. Now check for a connection between ground and the ppl/wht wire then between ground and tan/wht. Now check for a connection between the two wires. There should be no connection/continuity between the wires or a wire and ground. Now take your meter and make sure that there is a connection between the ppl/wht wire at the o2 connector and the PCM connector (you may have to extend the test lead on your meter by attaching a piece of wire to the end of it) Check the tan/wht wire in the same way.

pjherring

I am have the same problem. S1B2 is at 440mv. I have check resistance at purple and tan wires between pcm and o2 sensor connector they are at 0. I have also check ground from connector to ecu also 0 resistance. The voltage from tan wire is 4.4 volts. and purple is 1.2 volts. Sensor does heat when key is turned forward for a minute or two. I have also used the S1B1 o2 and it does the same thing on that side. Any ideas?

pjherring

Anyone experienced this issue?

pjherring

When i first noticed the voltage a 440mv constantly. I pulled over let the car cool down and felt the o2 sensor and made sure all the wires where still attached. Well after feeling i noticed the wires where all attached but there was a dent in the side of the sensor so i changed it and same problem. Thats when i did all the resistance test to make sure all the circuits were ok. Could the sensor shorted out and cause the pcm to short just on that one sensor.

psiconversion

iTrader: (5)

PJ,

Is the car bouncing in and out of closed loop?

Jon
PSI

pjherring

S1B1 is constantly oscillating between 100 to 900 mv

pjherring

any idea?