Twice now I've gotten a check engine light and with in 2 days it has cleared itself.

Any ideas what it may be?

I didn't even know a Check Engine Light could self clear without hooking up a diagnostic tool.

 

have you hit any water puddles lately ?
I ask cause once while driving the jag I ran into a small h20 puddle & the car’s check engine light illuminated which @ the time was quite worrisome, after continuous driving the rest of the day the CE light cleared. Didn't even have enough time to drive it out to my mechanic but later after some online research I found that its quite common for this to occur. Just giving you my 2cents hopefully this comes along as helpful. Anyhow please keep us here @ the forums posted on what you find out. Good luck!

 

Lightts go off depending on the code but the code is stored and still there. For instance. I have a 07xk right now she said the light comes on and then goes off. He's is a p0128 thermostat below temp threashold(it doesnt heat the engine up fast enough cause the seal on the t stat is torn and bypasses coolant) it needs a new t stat. Thats a "for instance"

 

...make sure that the gas cap is put on tight.

 

Fortunately it hasn't rained where I live for the past 4 months so no puddles, but rainy season is coming so I'll be watching out for big puddles.

Checked the gas cap, good advice, start simple, but it was on nice and tight.

Had a guy do a diagnostics and there it was, a P0128 code saved in the ecu.

Just ordered a new t stat plus gasket for $17. What relief it's a cheap fix. In general the parts prices for Jag have been outstanding. Everything I needed comparatively for my previous BMW X5 was twice as much.

Again thank you for the awesome help troubleshooting this.

Mike

 

Where is the OBD socket on these cars?

 

Right above the hood release for US cars, I would guess it is the same on the drivers side for UK.

It's up and underneath right where the lower leather trim ends,

 

and people think i have to touch a car to diagnose it

 

My car did just like Brutal said. Mine would come on and clear itself. I checked it and it was the thermostat code. Had it fixed under warranty.

 

The same thing happened to my 2009 XKR Portfolio about 8 months ago at well under 30,000 miles. The check engine light came on, dealer replaced the thermostat under warranty. That cured the problem and my check engine light hasn't come on since that repair.

Seems like a large number of 2007-2009 XK/XKRs with check engine lights due to bad thermostats. Since other models use the same engine, I suspect this problem isn't exclusive to XK/XKRs. I've owned quite a few different cars over the last 40 years and this is the only one that ever needed a new thermostat at under 4 years and less than 30,000 miles. Lots of bad thermostats leads me to believe there was a design defect.

Can any of the Techs out there let us know if the replacement thermostats are identical to the old ones or are an updated design? Just wondering if I should expect my new thermostat to die as soon as my car is out of warranty.

 

its not that common and its a rubber seal that comes dislodged slightly on 1 side and the t stat wont seal tightly. Its a much better failure than previous designs..(Overheating and stuck on the side of the road ) since it only leads to slightly slower warmup. This is more noticed by the ecu and not the owner

 

Same thing happened to my 38k 2007 XKR last week. As you say if it wasn't for the CEL I wouldn't have noticed anything. Very happy not to be seen at the side of the road with steam coming out of the engine bay! Was repaired under CPO warranty.

 

my 2008 XKR Portfolio, CEL came on for 1 day, off for 3 days, back on 1 day, off 3 days for several cycles. Cat Converter failing - new Cats under warranty problem gone for 2K miles now

 

Me too! At around 29K miles, my check engine light came on and my dealer said the catalytic converters went bad. They were replaced under warranty.