Check engine light

The CEL and the level of fluids don't have a relationship. That's why you probably have separate lights for things like oil and temp.

The ECU monitors sensors related to vehicle emissions and adjusts certain settings to maximize performance and fuel economy accordingly.

Yes, a loose fuel cap, as strange as it sounds can cause problems and should be checked.................but nothing is ever that simple.....at least with my luck... ;-)

The first, most suspect culprit that triggers a CEL is the O2 sensor located in the exhaust line. If it's old, then it may be due for a change.

From there, you'll need to get the codes pulled for a more detailed read on the situation.

Let us know how it goes.

BTW - What type/year/engine vehicle?

Cheers,

Jules said:

Is this an easy DIY job? I have a good set of tools and a garage to work in. I've done stuff like brake jobs, replace headers, exhaust work and replaced shocks myself. Any tips on where to buy O2 sensors for a 1996 Rodeo? Should I just replace them all?

Click to expand...

Yes, this is a definite DIY job with your stated experience. I think your setup has two? Pre Cat and Post Cat? If you can afford it, I would definitely change out both to 'zero-time' the sensors and start fresh. Before you start, you might want to spray them liberally with PB blaster or some other decent penetrant.

The defacto gurus most of us use is here:

http://isuzu.stcharlesauto.com/index.asp

Ask for Merlin when you call although anyone in parts can help, but Merlin is well known to most of us.

I know that the senors for my wife's Honda cost stoooopid money so be prepared for sticker shock - and having said that, I would stick with ISUZU because I've heard many complaints of aftermarket sensors sending erroneous signals, confusing the ECM and thereby causing more erratic CEL indications thereby blah blah blah.......

Good Luck, keep us posted.

Cheers,