Page 1 of 1
No Power to in tank fuel pump
Posted: Fri Jan 10, 2014 10:45 am
by Peebee
My old 2.0 litre HDi 406 will not start. I could not hear the pump, so having had this fail before, naturally assumed that this had failed again so without testing just ordered a new one and replaced. However, still no joy, so have done what I should have done in the first place and tested the supply to the pump, nothing.
I have gone through all the fuses and none have gone.
Any ideas as to why no supply is getting to the pump would be gratefully received.
Re: No Power to in tank fuel pump
Posted: Fri Jan 10, 2014 11:12 am
by 406owner2
Have you checked the relay itself ? specifically what it's doing, it also could be seen to be faulty, but in actuality it isn't. On my petrol 406 one of the relays in the double relay activates the pump. Also check if the relay is receiving power from it's plug.
I'm still not exactly sure how i managed to get the relay to do what it is suppose to do by the ecu in my car, but my relay now does the right thing and my petrol pump works.
I'm thinking perhaps my car's ecu sensed low water or low oil the shut off the relay, but then again it could have been something else.
Re: No Power to in tank fuel pump
Posted: Fri Jan 10, 2014 11:49 am
by lozz
Have you checked the Inertia switch?
Re: No Power to in tank fuel pump
Posted: Fri Jan 10, 2014 12:07 pm
by Peebee
Right, I was about to check the inertia switch so thanks for the reply. I have checked the double relay and that seems fine, clicks on when ignition is turned on, then a second click on, after about ten secs one set of contacts switch off, so about to go and check the inertia switch, freezing cold too.
Re: No Power to in tank fuel pump
Posted: Fri Jan 10, 2014 12:18 pm
by Peebee
Voltage getting to inertia switch, but no further. The continuity checks from the switch to the pumps fuse, so surely it must be the switch.
Re: No Power to in tank fuel pump
Posted: Fri Jan 10, 2014 12:24 pm
by Peebee
How do you reset the switch, or do I need to replace?
Re: No Power to in tank fuel pump
Posted: Fri Jan 10, 2014 12:25 pm
by lozz
Reset inertia switch?
just press it downwards,
Re: No Power to in tank fuel pump
Posted: Fri Jan 10, 2014 12:46 pm
by Peebee
Inertia switch it was, thanks for everyone's help.
What a pain in the bum.
Re: No Power to in tank fuel pump
Posted: Fri Jan 10, 2014 1:17 pm
by lozz
Peebee wrote:Inertia switch it was, thanks for everyone's help.
What a pain in the bum.
ok brilliant,
pay my receptionist on the way out. dont slam the door,
Re: No Power to in tank fuel pump
Posted: Sat Jan 11, 2014 10:23 am
by steve_earwig
Nicely done lozz
I always forget the inertia switch because I've never had a car with one

Re: No Power to in tank fuel pump
Posted: Sat Jan 11, 2014 10:30 am
by jonsowman
lozz wrote:pay my receptionist on the way out. dont slam the door,

Re: No Power to in tank fuel pump
Posted: Sat Jan 11, 2014 5:28 pm
by lozz
Ithink the Inertia switches,shouid be the first thing people shouid check,
No noise from pump give it a Press. costs nothing,
Some garages wouid Make a meal out of it, a decent hole in the road can trip these off or even giving the bonnet a slam,
Re: No Power to in tank fuel pump
Posted: Thu Feb 06, 2014 9:25 pm
by JimH240
Guys,
Can someone explain what an inertia switch is /does? Where can it be found?
Re: No Power to in tank fuel pump
Posted: Thu Feb 06, 2014 10:28 pm
by Doggy
It opens automatically in the event of severe decelleration - to shut fuel off in an accident.
None of my HDi's have had one, AFAIK, but I believe it is to be found on the nearside front suspension turret, or therabouts. They're usually red......