Hi all this is quite a story so please bear with this newbie.

At the end of last year my beloved 2011 XF started showing the Low Voltage warning on the dash assuming the battery maybe on its last legs had it checked but came back absolutely fine. So took the car to a trusted local independent who diagnosed the alternator was on the way out so this and the belt were replaced but they couldn't clear the warning!! After doing a bit of digging they discovered that the rear fuse box was in poor health due to water ingress so this was replaced with a new genuine jaguar one and reprogrammed.

Wonderful the low voltage warning was gone but shortly afterwards the check pedestrian system flashed up!!!!!

I have an Icarsoft v3.0 so plugged it in and cleared the fault in case it was a glitch but as soon as the car is restarted it comes back on. Checked all the sensors and system and can't see anything obvious. The vehicle hasn't been bumped or damaged.

Ran full scan and the only code that comes up is U3002-81.

Car is running perfectly and all other systems are fully operational any of you knowledgeable people out there got any ideas what is going on???

That Jaguar U3002-81 code is a power supply problem to a control module, not a single failed sensor.

One or more modules are seeing unstable, incorrect, or interrupted voltage.

Most common causes (in order of likelihood)

• Weak or failing battery - Jaguars are extremely sensitive to battery voltage—even slightly low.

• Poor ground connections -corroded or loose chassis/engine grounds.

• Charging system issues - Alternator overcharging, undercharging, or voltage spikes.

• Blown or high-resistance fuses Especially BCM / PCM / Gateway fuses.

• Water ingress,vVery common in Jaguars (BCM, boot modules, footwell wiring).

• Recently disconnected battery or jump start Can trigger this code temporarily.

First port of call make sure your terminals are super clean, making sure the ground has a good clean connection.

Running charge voltage should be 13.7–14.7V... anything over 15 means bad alternator or regulator. Are you sure you got right alternator?

Hi thanks for getting back so quick . Yeah the alternator was an approved jaguar one, the battery is showing about 12.8 when the engine is off and 14.4 when running so that is within the parameters.

The rear bcm module ( fusebox) was replaced with a genuine brand new jaguar one and reprogrammed as the one that was in it had dragged due to water ingress so the car the car is no longer showing low voltage that has gone as have all the fault codes that were related to it when you run diagnostics. The warning is now "check pedestrian system" which has confused me somewhat as that was not there before