Hi. This is my first post and sure wish it could have been under a better circumstance. I have a 2002 XJR100. Everything was great until this dreaded "engine failsafe mode" first appeared.

I did a bit of research on this forum and realized this is a much discussed problem here, but every instance the codes pulled were very different and it left little to go on. So if you guys don't mind reading through another incident report, I'd like to report my encounter and hopefully someone can strike gold for me.

Error messages: DSC/TRAC not available, engine failsafe, restricted performance

Lights ON: CEL, Brakes (occasionally)

AC unit display: "ER" letters showing, beeps severals times upon accessory power turned on

Engine Codes: 1000, 1637, 1643, 1979(occasionally)

So, can someone shed on light on this particular case?

 

New battery time. These cars are horrendously sensitive to low battery voltage - and they will still crank OK.
At the very least get the battery tested.
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+1 on the battery. Just to throw in related issue, check/clean/grease all the power and ground posts while you're at it.

 

I did take the battery to my local autozone and ran a load test. Test showed battery ay 94% rating. Is this good enough?

 

That's fine. Check the terminals as Jim suggests, also check the battery voltage at the posts with ign on and under the bonnet at the main fusebox feed to make sure it gets through OK.
The starter is on a separate circuit from the electronics.
Please post the readings.