2003 S-type (v8 base)-US model.

On driving this morning I notice the engine light coming off and on. I tried counting the number of blinks but there was no rhyme or reason that I could find. Sometimes it blinks 14 times, others 7 times, and then others 8 times. It does stop blinking and it seems like everything is fine, and then out of the blue, a few seconds (5-15) it comes on again. I notice no unusual behavior from the engine.

 

A blinking MIL indicates serious misfire situation where catalyst damage is occurring. Find and correct the source of the misfire(s), or P0420/P0430 is the result. What DTCs are stored?

Do not operate the vehicle under conditions that cause the MIL to flash.

 

Blinking = Bad. The flashing light is intended to get your attention to help avoid damaging the catalytic converters.

Straight from the horse's mouth:

"If, on the first trip, the misfire is severe enough to cause catalyst damage (more severe than excess exhaust emission), the CHECK ENGINE MIL will flash while the
fault is present..."

See page 6 here:

http://www.jagrepair.com/images/Auto..._OBD_II_R2.pdf

 

Thanks for the replies. I just got the car back from a shop earlier in the week where they reset the trim levels. It drove fine for the past few days before this light coming up. Do you think trim levels changed on their own or there's another problem (injectors-which I've already replaced) or coil...etc? I haven't read the codes on it as I don't have a reader-need to rely on the shop for that. I do most of my maintenance and mechanical work and would like to try to isolate the issue before givnig it back to the shop again.

 

Every modern Jaguar owner needs to have a diagnostic code reader capable of reading both OBD-ii and Jaguar's proprietary chassis codes. It will pay for itself in no time...

 

Also, one that reads OBD II live data. e.g. fuel trims

 

Your working blind?
Get a scanner as it will be required for any type of repair.
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Ok I had a mobile mechanic read my codes, the two major ones were cylinders 4 and 5 misfires. I've replaced all the plugs (even though the previous iridium plugs were 4 months old and looked very clean.) Aside from coils going out, is there anything else I should be chasing for these misfires?

 

Misfires can also be caused by vacuum leaks. That's why watching the LTFTs and STFTs is important.

 

I've had two different shops do vaccum tests for leaks and nothing popped up. These tests were in an attempt to resolve a primary starting and cranking problem. I've also looked the car over after getting it back from the starting problem having been fixed, and can't find any loose or cracked vac hoses.

 

Watching the OBD trims is the usual & quite easy way.

 

Is there a recommended OBD scanner/reader that a layman could buy and use?

 

An elm327 will do if you want really cheap.

 

When I look up elm 327 it just gives me OBD Bluetooth adapters. Wondering if there's a handheld type computer scanner that I should use? I don't want a piece of crap AutoZone one but I don't need a multi-thousand dollar one. I need something that I can read codes reset things, turn off damn battery light!

 

https://www.jaguarforums.com/forum/g...-%2A%2A-33347/

also see posts on Foxwell & iCarSoft

 

If your "battery light" is staying on, it is an indicator of a problem with the alternator or battery itself. There is one exception to this, if the alternator has been replaced with an incorrect aftermarket unit, or an improperly rebuilt part, the battery warning lamp will remain illuminated even though the alternator is otherwise functioning correctly. Unfortunately even an expensive, "pro level" scan tool will not correct this...

The above has to do with an incorrect regulator/control unit being installed in the alternator. Been to Autozone lately?

 

Yeah, the battery light caught my attention, too. There is no "reset" for the light. It's a fault warning from the charging system. If the fault is active (or a non-stock alternator is installed), the warning light will be illuminated. To turn off the battery light, you have to correct the underlying condition. Once that is done, the light will turn off by itself.

Either way, I'd check the output of the charging system. Low system voltage can cause all sorts of weird problems. On a 2003+ model, you should see approximately 14.5V at the battery after engine start. After a few minutes, the voltage should taper off around 13.7V.

 

Yes I've heard from the last shop I had my car in it would not be resettable (the battery light). I've had two mechanics run charging system tests and I think it is an Autozone alternator causing the issue. It could be the battery but it looks to be a properly sized Motocraft one. Though I'll check the voltage on that the next chance I can.

 

Your alternator is a Denso product; A couple of years ago I purchased a genuine Denso reman unit and it was perfect. Denso is the OEM for the engine management system on your car.

 

What is the idle speed suppose to be.