V.MoMO

iTrader: (1)

when i replaced the cat i could not take out the secondary O2 sensor even after putting all my weight on it. i then went to the junkyard and got a primary o2 sensor off an accord(93-94 i think) and addapted it to my secondary O2 plug. i connected all the wires with the same colors together, black to black, gray to gray and theres was 2 whites which i took a chance with.

my question is are pre and post cat sensors not the same?

why is it telling me theres a malfunction in the primary sensor curcuit when its the secondary curcuit i messed with?

may i have to go back and reconnect the the two white wires differently?

Former User

Is 7.5A dash fuse 15 blown?

V.MoMO

iTrader: (1)

i never thought about that, i'll go check it right now

V.MoMO

iTrader: (1)

ok so i dont have the actual fuse diagram but im guessing the fuse is on the middle row and all the 7.5A fuses are working and yes they are the correct fuses because not too long ago i had a hand drawn diagram but i lost it. so that probability is out.

could it be that i connected the two white wires wrong?

Former User

NOFX fuse diagram link

The proper way to test fuses is to measure voltage at both top test tabs when the fuse is installed. Click the Fuses link in my signature.

V.MoMO

iTrader: (1)

i have a mini tester that came with the fuse kit that i bought and shows when a fuse is blown. i know #14 is the keyless entry fuse which my car does not have so no fuse there and i tested the one to the right of it and the LED on the tester came on for that fuse

Former User

Measure the resistance across the two black wires for the heater element of the primary O2 sensor. It should be 10-40 Ohms.

V.MoMO

iTrader: (1)

thats where its gonna get hard, i dont have a multimeter(?)
i could probably borrow one from the parts store but that will have to wait till tomorrow as i have to go to work in a few hours and the car is hot right now from driving it, dont want to burn myself on the exhaust manifold

Former User

Yes, you need a multimeter. I have a Harbor Freight Tools store near me that sells a basic digital multimeter for $3.

V.MoMO

iTrader: (1)

RON, i tested the resistance and got 14.3-14.5 for both so im guessing thats within specs

Former User

Very good. Now unplug the primary O2 sensor and measure voltage (to body ground) at the Blk/Yel wire terminal in the O2 sensor wire harness connector with the key in ON(II). You should measure battery voltage.

V.MoMO

iTrader: (1)

i got 11.93 volts

Former User

Very good. The Blk/Wht wire in the O2 sensor wire harness connector grounds at the A6 pin of ECU connector A. With the O2 sensor connector and ECU connector A unplugged, check the Blk/Wht wire for continuity to body ground from either end as well as end-to-end continuity. These tests tell you whether the wire has a short or open.

V.MoMO

iTrader: (1)

i didnt get the continuity to body ground part but when i did end to end i got 0.04.

also i think i found my problem in all this.
check this out, its from the secondary o2 harness. i dont think thats supposed to be there haha. also it wasnt connected. i'll connect it later and i'll see what happens when i clear the memory.

Former User

The wires for the secondary O2 sensor were definitely tampered with. But the altered wire in the picture is for the input O2 signal to the ECU not for the heater element, so P0135 is a separate issue.

The wire tampering was likely to hide the bad cat you just replaced.

Testing for a short (=continuity to body ground):
Touch one meter probe to a wire terminal and the other to body ground. There should be no continuity (=high or off scale Ohm reading). Also do this same test on both the Blk wires of the primary O2 sensor itself.

V.MoMO

iTrader: (1)

besides that code i dont get anything else.

can you help me on checking continuity to body ground (how do i wire things, put the probes so that it gives me a reading, all it did was show a one on the screen when i tried) or is the reading i got for the end to end test enough?

Former User

Your end-to-end test shows the wire is not broken. It does not tell you whether the Blk/Wht wire has a short. Read my last post. It tells you how to test for a short. Do the short test for the Blk/Wht wire in the wire harness and also the Blk wire in the O2 sensor connector.

V.MoMO

iTrader: (1)

when i would probe the terminal nothing would change on the screen. all i get is one on the screen no matter if i touch anything or not

V.MoMO

iTrader: (1)

great news for now, i just drove the car and the cel light is GONE!

normally it would go on in about 2 seconds but just ran an errand and its gone. i got rid of the resistors(?) that where on that wire but didnt connect them and no cel. cool i guess...

Former User

Someone has clearly tampered with the O2 sensor wiring in your car because the disconnected secondary O2 sensor should be throwing a code. This makes me wonder whether the O2 sensor and heater element wires are swapped between the primary and secondary sensors. You might want to check this.

V.MoMO

iTrader: (1)

alright so the nxt day of driving the car the CEL came back on and i figured it would be the iput wire not bieng connected. i did end up connecting it and cleared the code. i have been driving for 2 weeks now and no more cel so im guessing there was a bad connection somewhere and after fiddling with it, everything is connecting right again.

so ron thanks for helping me find my way around