My engine light came on which I suspect was a lose gas cap. How long do I wait for it to reset before I make an appointment to get it looked at -

 

If it's fixed (and only if) 3 engine warm ups.

The code will remain stored harmlessly after that.

 

cool thanks think I am on 2, maybe 1 - I have my 48K service appointment tomorrow anyways - hoepfully they don't charge me the 175 dollar fee for investigating the engine light since I am under warranty still ..

 

and it went out - looks like it was the gas cap.

 

annnd..it came back on again today after a car wash. I have a service appointment next thurs...I will just bring it up there.

 

There will be codes stored that tell them what's going on and they can diagnose. Without that it's just guesswork

 

I have an odb2 reader - and got the codes - looks like an o2 sensor is bad but I will let the service person tell me what is wrong.

 

I had to have one replaced under the same circumstances. Was not thrilled about a check engine light at 12K miles. It's free and painless to you for them to fix it.

 

I've always wondered about the OBD codes coming from the various sensors. Doesn't the error mean the sensor is reading an abnormal level of some gas and not necessarily that the sensor is bad? I've always cleaned the MAF sensor as a first step and never had to replace an O2 sensor.

 

Realistically O2 sensors are wear items being in about 600C exhaust but they usually last a good many years.

Of course it can still be a fault with wiring etc instead.

 

As an update, I just got the engine light again, and I presume that it will again be the O2 sensor. I go to my dealer next Tuesday so we shall see. The last one was in October of last year, I think. The good news is that it didn't freak me out this time.

There are 4 sensors, so I figure I'm halfway there and totally expecting the other two to fail at some point. My service adviser said they can't proactively replace the rest of them. They each have their own code and they submit the reports to Jaguar for warranty payment.

My dealer is about 90minutes away so it's a beast to deal with. Usually causes me a half or a full day off to visit my dealer.

What will be interesting is if it's the same sensor but I'm not really expecting that. I'll update this thread if it is.

 

See my post #9

 

There are codes for bad readings and other codes for bad sensors.

I had the latter kind and the sensor was bad (tested heater ohms - open circuit). Replaced and all was good.

People commonly get lean codes and they rarely mean it's the sensor - but then that's what the Jaguar docs say so people just read them
(Read forum posts as well.)

 

Understood. But you having several bad/open sensors is suspicious and the dealer claiming it was a guessing game doesn't bode well. My understanding is OBD will pinpoint an open sensor. Anyway, hope your 'fix' lasts.

 

I would NOT change any O2 sensors unless you get a code.
As was said above they have a pretty long life!
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If it's a bad O2 sensor fault code and it fails at the same location right after clearing the code then change it.

 

That's good advice and if you really want to be sure swap the O2 sensors from side to side and see if the error follows the sensor.
It should IF the O2 sensor is at fault.
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I had the irritating engine light and discovered that it was the knock sensor which is definitely not a minor issue. So be careful. It is not always the gas/petrol cap. Get it checked out asap.

 

If you're in California, it takes about 200 miles of "normal" driving to reset the SMOG and Catalytic Converter systems.