My XJR 2000 has 150,000 km on it and is my daily city driver.
A couple of days ago the engine started to run rough after idling for a few minutes. My ADBII reader gave me P1642 and P1638 error codes. I also had ASC/ABS/Trac show up a couple of times.
Yesterday the engine kept running rough and I even got Gearbox Fault message at one point. I was able to make it home to my garage luckily.
The battery is only like a 1-year-old. I did a battery hard reset and tried to start the Jag today but no luck. The engine cranks but no start.
I’m afraid I’ll have to ask the Jag service center again.
Advice much appreciated.

 

The P1638 is an Instrument pack (IPK) to ECU loss of signal, which would lead to the next code by the look of things. It's either a short circuit or earth issue so you need to trace and check the IPK connection and earths to it an ECU as a starting point.
Battery to load check if it's been left for a long time.
Engine coolant temp sensor....how old?

 

@Sean B thank you for your reply
Yes I looked up the error codes myself as well.
How do I check the IPK connections and earths?
The cat has been running ok for quite a while and battery should be fine.
I've never changed the engine coolant sensor.

I looked through old threads with P1638 errors. I found this by @jimlombardi
https://www.jaguarforums.com/forum/x...estions-63284/
There he mentions how he some instrument cluster light bulbs not working. After replacing these his P1638 problems were gone.

I have actually recently seen the light behind the tachometer (RPM gauge) is out.
Could this be a similar situation?
Does anyone know how do I go about and replace this?

Regards,

 

I see what you said about the battery but probably worth checking its voltage carefully just in case.

 

@JagV8 Thank you. I don't have a battery tester but will try to get one. A couple of months ago I borrowed one and things looked ok.
Today I replaced all the 4 T10 larger instrument cluster light bulbs. I also sprayed all the connectors with electronics cleaner.
The dashboard lights up nice and brighter now but.....
Still no luck on getting the jag to start. Frustrating.

 

Another possibility to consider might be the solder migration issue on the instrument pack circuit board?
(search words "instrument" and "solder")
E.g. https://www.jaguarforums.com/forum/x...r-tsbs-240882/

 

@Chirpy thanks for that. I'll check.
I called the road service. I had the battery checked by them. 12.4 V, so pretty much on the low side.
They added several battery chargers on the Jag and tried to start but no luck. The engine sounds like it's just about to start.
We had quite a bit of gasoline smell so no problem with pump we assumed. We removed the gas pump fuse and tried to start for a while in order to drain any excess fuel in engine. After that tried again to start but still no luck.
In the end they had to transport the cat to the service center.
Frustrating.

 

The smell of petrol and almost running might just be 'bore wash' - these cars are infamous for it, especially after a cold start, quick move or short trip, then shut off....come to start it again and it just cranks, with more than a whiff of fuel...
The recommended procedure from literally hundreds if not thousands of posts on here is to remove the spark plugs and add some engine oil to the bores so the engine can build compression. No need to do both sides I think one bank will do it, the easiest side to access the plugs.
Hold your foot to the floor with the gas pedal as you crank and it will start eventually - obviously a fully charged battery too.