Hi, My 01 XJR X308 has started to get moody and I get the engine failsafe mode + Traction not available etc. Had Pulled the code and it was U1261 SCP (-) CircuitFailure. The only other thing I have observed is the central locking system has been a bit erratic with the vehicle auto locking on its own etc.Have been searching the forum for this code and not finding much. Most posts are referencing a failing battery as the culprit. I have a 1.5 year oldBosch Premium BatteryPart#:49-850BAGMbattery, but don’t drive the vehicle more than once every 14 days or so. Plan to pull the battery out tomorrow and have it tested thoroughly. Has anyone else encountered this and are there any other areas I should be looking into to get this sorted?

 

This is what I came across... U1261 Jaguar Auto Trouble Code With All Car Models | Auto Trouble Codes - AutoTroubleCode.com

For your battery, by chance are you using a Battery Tender or similar device with that roughly 14 day interval? That device will keep the battery up and fresh until its to be used.

 

If you drive the car only about once in 2 weeks, and go for relatively short drives, it is likely that the battery state of charge has gone down to a point where, although it can still crank the engine, its reduced voltage causes electrical/electronics malfunction. X308s electronics are very sensitive to battery voltage.

To check the state of charge of your battery, you don't need to take it out - just measure the voltage on the battery terminals with a multimeter with the engine off. If it shows less then about 12.1 volt, its charge is rather low. You should then recharge it with a battery charger but make sure you disconnect the negative battery cable before connecting the charger to the battery. You should use a proper regulated ("intelligent") charger and leave it connected to the battery until the charger automatically switches the charging off. You can also use a trickle charger but it will take days (a week or so) for it to recharge the battery that has gone down to the mentioned voltage.

After you have fully recharged the battery, re-connect the negative cable and see if you still have any trouble after starting the engine. Also check the voltage on the battery terminals while the engine is running - you should have 13.5 to 14.2 volts.

 

Actually a trickle charger doesn't trickle charge when recharging a battery, so it only takes overnight for it to complete a charge. It trickle charges after it has fully charged the battery and allows it to bleed down about 1.0-1.5 volts then reengages to top off the battery. Cheaper models may only do a simple trickle charge, but a proper one (like Battery Tender) does the charging without burning out the cell composition and maintaining a proper charge.

Britrover...aren't you over in Tampa?

 

@ Highhorse - Yes Monsieur, based out of Clearwater. Which battery tender unit do you recommend? Automotive

I pulled the battery out this morning and have dropped it at Auto Zone for a slow charge. Picking it up tonight around 1800 and will have it tested prior to plugging it in.

 

Battery Tender Plus PN: 021-0128 is what I use, I have 3 of them, you can get for around $45 on Amazon ...can't find my extra at the moment, I think its buried in the Corvette?

 

@ Highhorse - Thanks. I will order it tonight.

@ M. Stojanovic - Battery tested at 12.1 volts this morning. When I picked it up this evening it was at 12.9 volts. I plan to drive it for a few days and have it tested again. Let's see how she behaves now with a better charge.

 

Hopefully, the gremlins will disappear with the fully charged battery. There are two things about the battery to take care of:

1. Check whether the alternator is providing good charging voltage - check the voltage on the battery terminals while the engine is idling and with the AC and the headlights on. If you read some 13.5 to 14 volts, the alternator is good.

2. X308's electronics slowly drain the battery while the car is sitting so, after about 2-3 weeks, the battery will lose much of its charge and may cause problem with the car electronics when the car is then started. To prevent the battery state of charge going too low while the car is sitting, it is necessary to top it up with the charger that you have ordered (leave the charger connected overnight), say once every about 10 days. Alternatively, you can leave the charger connected all the time while the car is parked. This will keep the battery in top condition.

Keeping the battery at reduced voltages (of around 12V) for any prolonged periods of time will cause a sulfation process inside the battery which will "eat" its capacity, i.e. considerably shorten the battery life span.

 

The engine turns over but will not fire, there is no spark. I do have a new battery with 900 CCA in her.
I know noting about cars but I did check every fuse, however without the car started that’s not reliable is it?
I believe the computer is no longer directing the car’s components on what to do because they messed something up!
Due to their incompetence I’m on my own and I’d like to know if a hard reboot/reset may correct this to get my car started?