Puma 2.4 Defender 110. Fuel pump runs when ignition off

Help. I’m at wits end. I’ve had my Defender 5 years and have had elec fault for 3 of them.
Ignition is off, fuel pump has finished purge and is off. Hours or even days later, pump switches on without anyone touching car. If not noticed it will flatten battery.
Fault is intermittent and will sometimes not happen for months.
I’ve checked and changed relay and this has not fixed it.
Had car in to auto electrician who found no fault. As I can’t predict when it’s going to happen I’ve not been able to get auto elec to see it when fault present.
Fault seems to clear when I’ve given the car a drive. That is, until next time.

The fuel transfer pump is incorporated in the high pressure fuel pump at the front of the engine, and is driven mechanically. It cannot run unless the engine is running. Your problem must lie elsewhere. Have you got any fault codes stored and read?

Thanks for quick response. Motor noise from pump is coming from fuel tank not engine bay

Just looked at your profile info which shows you have a 2015 puma, which has the 2.2 engine. My previous post was based on your thread title which says 2.4 engine. The 2.2 has an electric pump in the tank. Your problem might be with the ECU so you need to get any stored fault codes to start resolving the problem.

I stand corrected. Just confirmed same on logbook. It is 2.2. Thanks for the advise I’ll get fault codes checked out

Is there any other factors involved when this happens, like after driving in wet conditions, or after any other things that might have been used aircon, lights, towing electrics etc when it does not happen if not used.

Most cases it happens during wet or very damp conditions. 1st thought it was just after going through standing water as seemed to be a pattern. All but one time it has been wet. Has happened a few times when car is sat in driveway for couple of days without being moved. Latest one was 3 days ago. Car had not been used for 2 days. Pump was running when I came out of house in the morning and battery drained. Much to neighbours annoyance, alarm went off when I opened car and I couldn’t switch it off.
I dont have aircon or towing light socket.

If nobody can find the fault, could you not fit an isolator switch to the fuel pump (find the fuse in the fuse box)
Then just flick the switch when you leave the vehicle.
In fact if you made the switch unobtrusive it would be a good extra security measure.

Same line of thought. Switch already ordered on amazon. Going to bypass relay which, as you say, adds extra security. Thanks

Can I ask if this problem was ever resolved, I'm having a similar issue now with my 2.2Tdci?
2 mornings I've come out now and the fuel pump has been running, the only common theme I can devise is both times the vehicle had been driven the day before in wet conditions.

My 2.2 started doing this when it was raining or damp when the wiring Loom shorted out against the gearbox due to corrugated road driving. Re-insulating the loom and padding it where it was chaffing sorted it out.