wing.jai

96 ek lx sedan is throwing a cel light for primary o2 sensor. i went to get a buy a new o2 senor by denso and install it in today. i start up the car a good 5-6 second the cel comes on again. i scan it and it say primary o2 sensor light. sensor cant be bad its brand new so i swap the 2nd o2 sensor to the primary plug and 1st o2 sensor to secondary plug and i reset the cel and start up the car again now it say im throwing light for the 2nd o2 sensor with the primary plug. so im assuming my primary plug is no good. my question is how would i check fo resistance or voltage to see if my wires on the primary plug is sending out signal or not. and what are the 1st o2 sensor wiring on the harness ecu part?

Former User

Post the CEL codes.

wing.jai

cel po135

Former User

The code is for the heater element of the O2 sensor. Check whether fuse 15 is blown and measure the resistance across the two heater element wires.

wing.jai

i scan it with the scanner it said po135 bank 1 sensor 1, fuse 15 shouldnt be blown because i check that recently (but i will double check). can you give me step on how to measure the resistance across the two heater element wire? electrical is not my thing but im willing to learn new things and very interesting.

Former User

The two heater element wires are black (sensor side of connector). Set the multimeter to read Ohms on the lowest scale. The reading should be 10-40 Ohms.

wing.jai

i double check the fuse 15. 7.5 fuse is still good. double check the code also "PO135 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1 )

wing.jai

its kind of late right now & i dont have indoor garage. so ill will check this first thing in the morning when i wake up.when i check it with the multimeter does the ignition gotta be on? if it doesnt read 10-40 ohms does that mean there a break in the wire somewhere or a short?

Former User

Key off, sensor unplugged. Make the measurement from the two black wire terminals in the O2 sensor connector.

Replace the O2 sensor if the resistance is out of spec.

wing.jai

okay will get back to you on this first thing tomorrow, but im thinking its my primary plug from the harness is bad because when i swap the plugs around like primary plug to 2nd sensor, and secondary plug into 1st sensor. then it will throw a p0141 and when i switch it back to how it was it throw p0135 and no p0141. thats why i dont think it gotta do with the o2 sensor and its the primary plug.

wing.jai

i double check the fuse 15. 7.5 fuse is still good. double check the code also "PO135 O2 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1 )

check the ohms today on the o2 sensor it was reading 13.9-14.0 so the o2 is good.

so what do i check for now ronj@ht?

Former User

On the wire harness side, now check whether the Blk/Yel wire from fuse 15 has battery voltage with the key in ON(II) and whether the Blk/Wht wire has an open or short.

goldenchild707

good luck

hyperblu

if the plug is bad hard wire it to test...

wing.jai

you mean check the blk/yel wire from the primary o2 plug with the ignition on for voltage ?

if so it show 12v

Former User

Good. Now check the Blk/Wht wire. If it's fine, then the ECU becomes your prime suspect.

wing.jai

alright ronj@ht i went to check the voltage for the blk.white red probe to blk/wire and black probe to battery ground and it reading at 16v with the ignition on.

am i doing it right?

wing.jai

its like 1v with ignition off. but when i double check it like .5to.7 v with the ignition off

wing.jai

sorry for the bump ronj@ht but get back at me cause ima be home all day and trying to get this fix asap. need to smog and regis the car.

Former User

You need to test end-to-end continuity and continuity to body ground (not voltage) for the Blk/Wht wire.

wing.jai

so from the blk/wire from the o2 plug in the bay to the ecu plug pin "A6" check for the continue sound? and from what to what for the ground? sorry for the trouble, bit scared and nervous when it comes to electrical.

wing.jai

please get back at me.

wing.jai

okay red probe on blk/white wire from the primary plug & unplug A from ecu black probe to ecu end pin "A6" check for continuly sound with ignition off no sound. and you said check for continuly body ground (not sure for this one) do you mean the body to the tranny ground?

wing.jai

not sure for the ground part but i put black prob to A6 pin on ecu end and red probe to body ground it reads 22.something to 23. something when i try to check for continuly sound, but no sound just those # shows up

wing.jai

oh my oh my scratch everything.

quadruple check o2 wiring color code. end up not my primary o2 sensor plug is bad. its my secondary o2 sensor plug not working. so i been checking the 2nd o2 plug this whole time. so not p0135 its po141

but blk/yel ignition on is still 12 v.
blk/whte wire need to check continuity end to end from plug to A5 not A6 correct?
and how to check for the body ground part bit lost on that

D14 – Sensor Heater 02 Signal (SH02S) white/red
D11 – Sensor Ground 2 (SG2) green/black
A5 – Secondary Heater 02 Control (S02HTC) black/white
A11 – Power Source 1 (1GP1) black/yellow