2002 406 HDi 110 battery going flat

[sarkysid]

Hi Everyone,
Sorry to repeat a similar fault but couldn't get an answer for my problem.
Car runs fine, battery charges fine etc,but battery is going flat when car is parked. Read threads here that its possibly the Fuel Pump Relay ? When ignition is off after being driven, you can hear a whirring noise coming from the off side front of the engine, possibly the fuel pump ? this stops when battery is disconnected, and stays off if battery is reconnected, if battery isn't disconnected then whirring continues, i guess this is what's flattening the battery ? Anyway, reading here its possible that the fuel pump relay is to blame ? but try as i might i cant locate it, i've looked inside the box with the ecu in but no relay there, any one know how i can locate this ? Is it part of the ecu and if so do i need to replace this ?

Also if i reconnect the battery and turn ignition on, but don't start the engine the whirring starts again, and does so till i disconnect the battery.

Thanks in advance

Regards

Stuart

[steve_earwig]

Hi there, welcome

The electric fuel pump (lift/ low pressure pump) is in the fuel tank, under the back seat. They all seem to make a similar noise, it stops after a minute or so, if yours carries on for hours then it's something you need to investigate. Fuse 16 seems to be the ECU feed, you could try pulling that to see if the noise stops. If not you actually have an audible symptom to look for, pull ALL the fuses one at a time until it stops.

The fuel pump is fed straight from the engine ECU on fully multiplex HDis.

[sarkysid]

Hi Steve,

Thank you for your quick reply.

The pump thats making the noise is on the front off side of the engine ( painted black ) . I will try the fuses as suggested and see how i get on.

Thanks again for your help

Regards

Stuart

[steve_earwig]

Offside, is, er, right hand/driver's side - it's all engine driven There are a couple of solenoids on the HP injection pump, maybe one is chattering