BubbaBob54

Hello Guys (Girls too)

92, Toyo 4WD Ext., 192K, 22-RE, Manual Trans ...
Ripped the wire pigtail off of harness/O2 sensor connection. Here's what I got...

Bosch O2 Sensor, 4 wires; 1 grey, 1 black, 2 white

Harness, 4 wires ; 1 black, 1 brown, 1 white/red stripe, 1 red/black stripe.

I plan to just hard wire this thing, but which wire goes where?????
Sensor black is signal +, gray signal -, 2 white are heater I think. But which truck wire is what...

Thanks for any help you guys can give me.

Bob

Elvota

You are on the right track.

1 wire is 12v
1 wire is ground
1 wire comes from the HT pin on the ECM
1 wire comes from the OX pin on the ECM

At least, thats' the way my '90 is wired.

I believe the HT pin lets the ECM heat up the O2 sensor for various reasons, and the O2 pin reads the signal. On the '90, 12v is supplied via the EFI relay, or when ever the key is in the IG2 position.

You'll most likely need to get a hold of a EWD for your model year to figure out where the W-R and the R-B wire connect on the ECM.

BubbaBob54

Thanks Guys...

I'll spend a little time with the schematics and see what I can see. Guess I should have just tied that dangling connector up and this would not be an issue now.

ewong

As far as I can tell (looking an an 88 Bently manual - FSM is in the truck which is back in storage)
Brown is ground
Black is sensor wire to the ECU
B-Y (black yellow) is to the EFI main relay (aka 12v switched)
G-Y (green yellow) is to the ECU as HT (akak heater wire)

Im SURE that BLACK and BROWN didnt change (those are common color uses).
So

Turn the ign on and see which wire gets "hot" when the key is on (me guess the ECU grounds the HT to get the heater to turn on - Toyota commonly uses a ground switched schema)

ralphalachichis

I recently purchased a 1988 4runner buggy it had a broken o2 sensor and was routed under the seat. There wasn't the rest of the wiring harness running under floor trim. I found a large pigtail next to dside interior fuse pabel, that in turn is my question is there a missing harness that has ben discarded. If that is the harness does anyone know the wires in which i can connect to.

Tuckerrobinson28

I ripped my o2 sensor out in the woods one day, I've been trying to find diagrams to tell me what wires go where and I can't find anything. The same day my truck died and now it has no spark, I was wondering if anyone has ever lost spark from a problem with an o2 sensor