My wife just bought a 98 Discovery that looks like it just came from the show room. However the check engine light is on and its shows no code when put on a scanner. It has 125,000 km's(75000 miles). I read somewhere that it could come on around 50-80,000 and just means its time for a complete service. We are getting all the things done do it that is list as complete service, hoes, belts , fluids etc. Meanwhile how do I turn the light off. Tried finding the module on right side kick panel but doesn't seem to be one there.

The lady she bought it from was running it on 87 octane gas, my wife is using 92 octane. Any help would be appreciated.

 

Stay with the high octane gas.
Are you doing all the work on it?
I bet you will find, the light that is on is your maintance light, not the CEL.
Download a free copy of a Rave CD, from my signature section below and it will walk you thru all you need to keep your truck happy including turning off you light.

 

There are 2 warning lights on the DI dash.
A red "service engine soon" light and a amber "check engine" light.

If it is the red one there will not be any codes.
That is the emissions reminder, you can reset it yourself.
Go to www.discoweb.org and look up the "tech section" and find the "how to reset service reminder DI".
Follow the directions, better yet print them up and stick them in your keeper's file folder for later use.

 

It is the amber check engine light. Would the former owner who used 87 octane gas have ruined the oxygen sensors or other emission controls?

 

No running 87 wont ruin the O2 sensors, but it will sludge up the engine and carbon things up.

If the light is on you should be getting a code.