I have a 1997 land rover discovery LSE model and I just bought 2 universal o2 sensor for my car. The only problem is that the wire colors on my car don't match the wire colors on the new o2 sensor that I bought. Could someone please tell me what the wire colors mean on my Disc: I have red, black, yellow, and white wires on the o2 sensors right before the catilc converter. I know one is the heater, two are for sensors and one is ground. but what order I have know clue.

 

I doubt you can wire those to your truck. You need to compare your vin to the correct 02's or they won't work and most likely you will need al 4 02's.
Are you currently having problems, any fault codes.

 

If it's not a 4-wire universal it won't work.
Download the Rave manual.
Look in the D1 electrical troubleshooting manual for the '97-'99 and do a find for "oxygen sensor" or go to pages 44-45.