HELP! I have a 2002 pre production 2003 S Type R (4.2L with Eaton supercharger) runs well, just had a tranny service and software update, however there seems to be a dead spot in the throttle (it was there before tranny service) when I am crusing on the freeway and want to accelerate/kickdown to over take etc, car takes a deep breath?, howls then it goes into limp home mode. gear box fault on dash! Revs around 2000-3000 depending on speed at the time of acceleration.Stop car, turn off ignition, restart all OK. Got me stumped. Anyone else had a similar probl

 

There isn't a dead-spot in throttle, but a fail-safe action by the ECU. Check for codes though there isn't a CEL. Likely cause is a lean situation brought about by a vaccume leak from a hose or gasket, exhaust leak before catalytic converter, failed MAF sensor, or throttle body (poor electrical connection or internal failure), be sure the airbox is secure and its hose connection to the air intake tube is snug-on and hose from air intake tube to drivers side cam cover blow-by port is snug-on too. Have the battery tested for a weak cell, as this will prohibit engine management electronics.

 

^ what he said

Get a cheap OBD tool such as elm327 and as well as reading codes check fuel trims at idle & 2500rpm - post what you find and hope for suggestions.

 

And further to getting codes from an OBD reader, if it's P1121/1122 it'll be a throttle body issue. Armed with the OBD reader, at the next 'event', don't shut the car off, plug the reader in and see what it says.
How many miles has the car done?

 

Caution: those look like XJR codes. Very unusual to get P1122 for an STR and I believe P1121 is not a defined code for the STR. It's a different PCM, isn't it?

 

could be right there JagV8, I assumed OBD codes where standard across Jag

 

No. There are separate codes PDFs, which very usefully describe the various things known / able to cause each code. When there are major engine-related changes there's usually a new PDF (so, the 1999-2002 S-Type has a PDF and there's a different one for 2003+, and so on).

There will similarly be ones for the XJ, the XK, the X-Type and so on. The same code is by definition allowed to mean different things (this is part of OBD so applies to any car make, model, year, engine, etc).

Using the wrong meaning for a code leads to major pain!!

(When you think how different some cars are, it simply has to be this way. Some have no EGR, some have a turbo, some have multiple turbos, some have an IACV (aka AAI aka ye gods so many names), some don't, some ....)

 

Thank you all very much for your prompt replies and help, I will check out as much as I can under the bonnet, re hoses etc when I get the car back from the Smash repair centre. Yes, in the meantime a learner driver did an illegal U turn in front of the traffic and I got hit in the passenger side!. Cant win a bloody trick.
By the way whats an OBD? I asume its a testing device which reads codes from the cars ECU? can I buy one?

Thanks again Jim

 

Yep, look here,
https://www.jaguarforums.com/forum/g...oved-**-33347/
also hunt for the codes list for your specific model and year, again on here or google it.

 

Always worth using google with
define OBD

works a treat

 

Thanks for the info on the OBD, lots of info on Google, just have to order one and make sure I have the right codes for my car. because apparently being a 2002 pre production model for 2003 can cause a few issues with identifying the car.
Even with the VIN fully quoted for spares.
Any one in Oz know a retailer that sells them?

 

Maybe ebay for an elm327, probably the USB kind.

 

Jim, you might already be aware but dont forget in the US the str was not released till 2003. We and the UK got it at 2002.5. Most people in spares (and that includes Jaguar spares) would also not even know what pre-production means. You need to tell them that its a 2003 model, or quote the VIN when the models were updated. Wisely Jaguar has dropped the preproduction numbers.

 

I think GLM Software are in Oz and sell such.

 

Thanks again gang, well its off to ebay!
Cheers