No dash, no start

[mikeanson]

Jumped in the car yesterday for a quick spin to keep it happy. Instrument cluster did not spark up and would not spin starter. Clock is running, interior and airbag lights are on. I can hear the fuel pump clicking and the climate control starts up. Put battery on charge overnight (it was new last year) . Tried again this morning - no change. When the rain stops, I will disconnect/reconnect battery, then check again. Since the clock is running, fuse 18 (drivers side fascia fusebox) must be intact. What am I missing? 2005 XK8 4.2L coupe. Thanks!

[ptjs1]

mikeanson,

Start by verifying what voltage is in the battery with a multimeter, rather than just assume there's a battery problem and charging it.

If the battery is +12.5v, then do the instrument lights come on in Pos 2? You mentioned the "airbag lights are on" but also "instrument cluster did not spark up", which is a bit confusing (to me). Which lights are coming on in the instrument cluster when you turn to Pos 2?

Paul

[mikeanson]

Hi Paul, thanks for the reply! If I remember correctly, battery voltage yesterday before I charged it overnight was 12.3V. This morning, it's 12.7V. When I turn ignition on, I briefly get both airbag lights on (passenger side and the one in the instrument cluster) but nothing else. I turned off climate control but when I turned it back on, I now get "Er" in the display and ten beeps. Waiting for the rain to stop again!!

[ptjs1]

mikeanson,

So in Pos 2, (not Pos 1), you're not getting lights for handbrake, alternator charge light, EML, seat belt light etc etc?

Paul

[mikeanson]

Well, that was very odd! Disconnected/reconnected battery and got some more lights on the main instrument panel, but still would not start. This also put the alternator and oil pressure lights on - which stayed on with door closed and car locked! Disconnected battery again and reconnected after 10 minutes and it all came back to life. Had an EML, which I cleared, starts, runs, no errors. Confused but relieved. Thanks for trying to help - I appreciate it!!

[ptjs1]

mikeanson,

The battery voltage on all Jaguar models from the x100 and the x350 onwards is really critical. The introduction of linked modules under OBDII and Canbus technology demands steady voltage and integrity. Anything less than optimal voltage and the car can throw spurious faults, instrument lights and starting & running conditions. So, it doesn't surprise me that clearing the faults, bringing the battery voltage back up and resetting things cured the problem. Well done.

Paul

[mikeanson]

Cheers Paul! I have had this car since 2016 and replaced the battery for the second time in 2024. Because it is not used every day, I give it an occasional charge from the cetek every now and then. I have never seen this behaviour before. The worst battery voltage related fault I have ever seen is when the abs warning comes up on turning over. So I learned something new today!!

[Lucky]

Since you don't use the car that much then rather than giving the battery an 'occasional charge' I would leave the CTEK attached whenever the car is parked up if you are able to do so. This means the battery is kept in top condition ready for when you take it out. Certainly that is what I do with my X100 (and the MX5).

[mikeanson]

I'm suspecting the dreaded alarm sounder battery is draining the main battery. Going to test that. I assume if I remove FUSE 9, it should stop that? It does always chirp on locking the car though, so I wonder if it is actually faulty. Presumably, current draw should be quite low. Measured at 30mA via F9. Doesn't sound unreasonable.

[Astromorg]

The total quiescent current from the battery, with the car fully asleep, should not exceed 30 mA. With that much being taken by the sounder, the total must be too high and part at least of the excess must be the sounder itself. As it has a connection to the BPM and a ground wire, a drain might still occur with only the fuse removed, so I'd disconnect it completely until the full problem is resolved.

[mikeanson]

Thank you Astromorg. Just waiting for a dry, non-freezing day so that I can get out and disconnect the sounder, then I can see if the battery will hold charge. If only I had a garage!!