Since having the car for three months now I have had the dash light up like Christmas tree perhaps 6 times with 20 or so codes. Always at startup but never the same, never popping up while underway, only at startup. Sometimes at cold start, sometimes warm after stopping for fuel or only for a few minutes. sometimes when wet and also when dry. I have had every possible error message on the dash from gearbox faults, cats error, headlamp faults, battery not charging etc. Sometimes the gearbox won't shift or the engine even turn over until I clear the codes using the Torque app on my phone. I don't believe any of the codes are real.

I have always been able to clear the codes, lock up the car, and then restart and all is well again for a week or so.

Battery is new and the system is always charging at 14 plus volts.

The car is garaged and has 60,000 miles. I drive it 2 to 4 days a week.

I've cleaned and tightened the grounds where I can find them.

I'm thinking some kind of stray voltage or even static electricity.

Is there any thought about going around the car and adding another three or four braided grounding straps at various places? Does this make sense? Could my OBDLink MX+ transmitter or GITANK Bluetooth receiver be causing this?

I don't want to end up getting stuck the time it decides not to recover. I've been on a few long trips from Virginia to Miami and Charlotte and Charleston. More trips planned.

Many thanks for any advice.

 

Do you leave the OBD dongle plugged in all the time? If so unplug it for a few days or a week to see if your Christmas tree has disappeared. I had the occurrence you describe once. I unplugged the reader and upon the next startup everything was back to normal. I have not had the problem since and I have a reader always plugged in to gauge coolant temp and battery voltage.

 

Had the Christmas tree one time, when I plugged in an OBD reader while driving. I agree with the above, pull whatever is plugged into your OBD port, and see if the problem persists.

 

The ODD2 port is permanently "live". A device left plugged into it will drain the battery. A partially discharged battery will give all kinds of spurious error codes and lights.

Graham

 

Fred, I think you may have found your problem! When I had my battery problems there was a statement that the Jag system does not accept a voltage higher than 14.3 volts. I had measured my alternator at 13.3 V and felt relieved.
You said "Battery is new and the system is always charging at 14 plus volts." Not good....

 

Just a note?
I have the OBDLink MX+ dongle. The MAIN reason I have it (Because it is a good bit more expensive than others at $140!) is that it automatically powers down and powers back up. So it does NOT drain the car because it shuts off. I have run it for months in my 2014 XJR which is a different car but with zero problems.
OBDLink MX+ Dongel
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I would always suggest starting with the simplest of things - your assumption that the battery is good/new. It is amazing how much junk is out there in batteries. About 3 months ago, I installed a new battery, it was fine for two months until a bunch of electrical gremlins started - I had all kinds of spurious dashboard messages, lights and very odd electrical behavior (lights blinking, wipers turning on and off, windows doing a stutter step opening and not closing, etc.). Turns out this new battery had some sort of internal fault and needed to be replaced. Once replaced, the car returned to normal, immediately. The fact that all of your issues occur at vehicle start (before the Alternator is doing its thing), I would investigate if you have a start-up, low voltage situation with this battery that results from the high cranking draw at ignition. Good Luck!

 

My cheap-*** chinesium OBD Bluetooth is inserted whenever I drive and removed when parked. I need it because I have all the TORQUE PRO stuff on my TSD. I've not had the dongle create a problem. Not yet, anyway.