I just got a 2003 4.2L from my Dad. It has 106K miles on it. I drove it from KY to FL between Thursday and Saturday. On the last 3 hours of the trip, the check engine light came on and stayed on for the remainder of my trip. I was in the middle of nowhere with no dealer in sight. Dad said this happened to him a few times when he was on long trips but the light always went out when he got home and the dealer couldn't figure it out.
I checked all the fluids, the gas cap was on tight, etc. The light stayed on Sunday when I moved the car twice but went out Monday on the way home from work and hasn't come back on.
Any ideas? The car never lost power or drove any way other than normal when the light was on.
Thanks.

 

No expert here but I would try using a code reader and checking any malfunction codes before anything else. My check engine light on the 2003 S-Type V8 has been on for a couple of years and I'm presuming that it's the O2 sensor. (the wife's 2001 BMW is the same) The cars have always run perfectly and the fuel mileage hasn't changed in either case. I don't think that it's worth the expence of repairing it. Good luck.

 

My check engine light was always on with my previous vehicle and the bulb eventually burned out-problem solved I was just speaking to a machanic about this the other day and he said the newer vehicles have way to many sensors and "their" malfunction is usually the issue, a friend scrapped his Cadillac as the sensors were driving him crazy. Obvious they serve a purpose under normal circumstances but if the vehicle drives properly and passes pollution control I wouldn't worry about it.

 

Get the codes! You may have a small problem that may end up being a big problem when you least expect it. You can guess all you want but the codes will tell you what is going on. You can go to AutoZone, PepBoys or Sears and get a reading. When you do write the codes down and we can tell you what they mean.

 

What you said, I got distracted. I would make sure there were no real issues first

 

Don't ASSUME what the cause may be!! Especially as a jag is not a bmw.

Also, don't ASSUME that all is OK because it drives OK and passes pollution control. If the light's on all is NOT ok.

A $20 (ebay etc) USB elm327 will work and saves getting codes from AutoZone etc. Heck, many a code will cause poor MPG so you'll spend that but not know - at the same time as maybe burning a cat out (and then it'll fail on pollution).

 

So the ELM scanner can tell me what's wrong even with the light now off? As I wrote above my Dad twice took the car to his dealer and they couldn't tell him anything w/o the light being on.

Thanks all for the responses.

 

So long as you don't disconnect the battery the codes stay stored for a long time.

 

As jagv8 suggests...read the codes off a scanner. You'll likely come across a 440 code or something close to this that suggests insufficient catalyst...up or downstream O2 sensor...replace the O2 sensors. Got the check engine light tonight. Stopped at mechanic and code was 400 series suggesting O2 sensor. It's happened before. he cleared the code and light. Will replace O2 sensors.

 

Further: if the battery hasn't been disconnected and the dealer could not find any codes - think hard before going back to that dealer!! If there's another, even a bit further away, plan on going there next time (for diagnosis).

 

The contributors are right here -- any tell-tale deserves investigation at least, even if the problem turns out to be spurious. Not all scanners will read the stored codes in your micro. There is a huge amount of information here on this website as to how to read, what sort to buy, what they will do etc. Generally, the more you pay, the more comprehensive the functions. If it turns out to be an oxygen sensor fault, at least your fuel consumption is likely to be better on replacement.
Leedsman.

 

I ordered an ELM so we'll see what the codes say.
The light was on for days and today it turned off.
And the car won't be going back to the original dealer as it's in KY and I'm in FL.

 

Is the light on at low speeds?

 

When the light is on, it's on at all speeds. It's off now. I"m waiting on the ELM device to try to see what the issue is.
Thanks.