Universal Oxygen Sensor Wiring Mess!

[Gumart1]

First off, a big HELLO to everyone! It's been nearly a year since I've been active here, and it's just great to see so many familiar contributors and also so many new members! Both my LS's (1991 and 1998) have been doing their jobs so well in the past year that I haven't checked in much.

I'm in the process of changing a bad 02 sensor on my '98. I couldn't find the universal Denso replacement that worked very well in my '91 last year, so I picked up an "SNG" universal 4-wire sensor from Oxygengeek.com. These are less than $32 each and shipping is free with two or more.

Both the Gen. 1 tutorial on Lexls.com and the SNG instructions don't match my color codes on the factory wires. The factory wires are white, blue, black, and black, and the replacement SNG sensor wires are white, white, grey, and black. I understand that there is a signal wire, 2 heater wires, and a ground wire, but I don't know the correct connections. SNG hasn't gotten back to me yet. Any help would be appreciated.

[Robert Young]

I would guess that your two black wires on the original sensor are for the heater and the white wires on the new sensor are for the heater (which shows the same color coding that Bosch sensors use). You can check this by noting the voltage on the wires without a sensor connected, one of the black wires will probably show something approaching battery voltage. The heater wires do not have defined polarity.

According to the paperwork that came with a Bosch generic sensor I used, the original sensor appears to have what they call a Type B color code. If true, the blue original wire attaches to the black wire of the new sensor and the white original wire attaches to the grey wire of the new sensor.