Hello,

I recently purchased my first Jaguar, a 2000 XJ8 with 100k miles. It is in excellent shape and was well maintained by the prior owners. After getting it home I went to work cleaning it up and made some minor repairs.

The engine compartment had likely never been cleaned so I carefully scrubbed it and rinsed with a garden hose. I got a couple of error codes when restarting that quickly cleared and everything seemed to go back to normal. I presumed because I got some of the connections wet.

A couple weeks later I replaced the front passenger door latch due to a faulty door lock and the heater control valve due to poor cabin heating. Both were used parts from Ebay. Some coolant spilled of course when changing the control valve and I once again used a garden hose to rinse around the heater hoses and firewall. When everything was buttoned up...I got the SCROLL OF DEATH...lots of error messages. I can't remember all of them but they included Wrong Part Fitted, Engine Failsafe Mode, Transmission Fault, etc. The gear selector locked in Park, and the Climate Control panel indicated ERR and gave a series of beeps whenever the ignition was turned on.

After a bit of fiddling and isolating the parts I had just installed (and lots of anxiety) I waited for the engine compartment to dry overnight and it fired back up and everything was fine.

It has been starting and running fine for a few weeks now, but last night while driving 60 mph down the highway I got a thump from the drivetrain, so I pulled over and got many of the error messages again including Engine Failsafe with a no-start condition. Climate Control panel in ERR and beeping again. I tried to start several times, waited a bit, but nothing. I then turned off the Climate Control and everything was fine again! It started up as normal and I was back on the highway.

Do I still have a wet or faulty connection somewhere? Battery is charged and shows 12.38 volts. The used heater control valve I replaced had a slightly different numbers on it but was identical in appearance to the original.

Any ideas? Love the car and I'm hoping not to get stranded.

Thanks

 

First stop is a code reader via OBD11

See what codes have been stored.

 

The problem is almost certainly a dodgy "CAN bus" connection. Dry out the connectors on the transmission module, the ECU, and the BPM.

BTW, was the heater valve actually bad?

 

Thanks,

I plan to pull the OBD codes this week.

In response to the CAN BUS connections, I am still familiarizing myself with all the Jag modules, locations, and connections...and yes, I have the 2500 page workshop manual...

Assuming this is a wet or sketchy connection...is there a most likely culprit in the heater hose/firewall area that got wet when I rinsed away coolant?

In response to the heater control valve replacement, the old one was not gummed up and the valve seemed to move freely but cabin heat was very poor...even on the highest setting. The used replacement seems much better, but the heat is not overwhelming. Also, it did drip some coolant for a few days after the fix but seems to have stopped. I assumed because I overfilled the reservoir...how full should the tank be?

Thanks again.

 

Poor heat can also be due to the aux coolant pump that moves hot water through the core more than happens naturally. The pump can be carefully disassembled and the worn brushes changed. There are links here and there on the techniques. Or can replace with another. Many of the current cars use similar, VW, Mercedes, BMW, Ford, Lincoln all have them depends how much you must maintain as original.

 

Maybe dry the connectors to the throttle body.