Hi all

I've had by 2011 XKR 5.0sc for about 2 years now but not used her much mainly because of Covid. In between lockdowns I did take her out a few times and dynamic mode etc. would not engage due to what turned out to be a faulty level sensor on the front right. Replaced that and all was happy again.

However now I have lost cruise control. In itself not a big deal for me, I never use the car on highway journeys, just blasting around back roads and performance is unaffected but it does bug me a bit to get yet another fault on a 48,000 mile car.

The codes are:

PCM - U-104-00 lost comm speed module
Speed control module - U-0401-81 invalid data received from engine control/PCM
B1142-13 intermittent ignition status
U0155-00
U3000-55

Needs a service so is this something obvious I can deal with or should I just pass it over to the local dealership and say "fix it"?

Thanks in advance

 

CHECK THE BATTERY!!!
Seriously, 88.6% of all electrical problems are because of a low battery state.
The battery should read at least 12.6VDC after resting for several hours.

 

88.6%! Very precise!! But good point, someone else said same thing to me. The thing is when I bought the car it had a brand new Exide battery fitted by the seller and I have used a Bosch 12v trickle charger on it ever since so I had kind of wrote that possibility off. But when I think about it, its logical I mean why would a load of faults occur just when the car is sitting there between start-ups.

So you are saying if I hook up a DVM/multi-meter without it being on trick charge and without being started and it should show 12.6v? And below that = problems right?

Thanks for your help.

 

Actual Trickle Chargers are known to overcharge and ruin brand new batteries as they force voltage all the time. A good battery MAINTAINER is a much better product as they only provide what's needed.
SO...
I'd say disconnect any chargers and let your car sit for a couple hours, then check the battery voltage. It should be 12.6 VDC or higher. Brand new batteries are nearly never fully charged when purchased as they sit around the factory until shipped, then they are shipped, then they sit in the distributor's warehouse, then they ship again, then they sit in the back stock of the retailer, then again they sit on the shelf. Plus, the manufacturer wouldn't waste time fully charging anyway.

 

Why do battery manufacturers provide warranties? Because they know from experience that some of their batteries are defective and won't last long.

Just because you have a new battery that's fully charged doesn't mean it's healthy. Get it load tested at your local auto parts store. They usually will do it for free.