Aygo - Fuel Pump Relay?

[Cribus]

Hi, This is my first post.  I've been an Aygo owner for years but this is the first time I've needed help and couldn't find the answer (usually on this site!)

My Aygo is a 2009 petrol model, only 30k miles, and recently it started running roughly, misfiring and cutting out now and again.  Now the car won't fire up at all, it turns over fine on the starter but doesn't fire up.  I noticed recently that when I turned the key I would sometimes hear the fuel pump, sometimes not, and now I don't hear it at all (I've lifted the back seat to make it easier to hear).  So presumably the pump or its relay are the most likely candidates.  I have a spare fuel pump relay to try first, but I just can't find the relay anywhere in the car!  Can anyone direct me?

I've tried the fusebox in the engine compartment and behind the dash on the right hand side, but I just don't see it.  Some people have mentioned online that some Aygo's have a separate relay box under the bonnet, in the area beneath the nearside headlight, but there is nothing there on my car.  Before I noticed the lack of noise from the fuel pump I had already tried new cam and crank sensors.  Just to be clear, when I turn the key the engine turns over fine, plenty of strength in the (new) Battery, but the engine just never fires up.

I've tried the Haynes manual but that hasn't given me any other suggestions for its location.  Wiring diagrams online seem to show it either mounted into the side of the fusebox in the engine bay, or in a separate relay box near the left headlight.  It's often marked as 'R4' in those diagrams.  But no joy in my car.  Any ideas please as I have none left!!  Many thanks, Chris.          

[XtraStuff]

Hello, Did not find so far in my docs the fuse for fuel pump, but apparently R4 the relay part of the hidden "fuse box BF01 with soldered 4 relays module" under the engine compartment fuse box.   ( https://fuse-box.info/toyota/toyota-aygo-ab10-2005-2014-fuses-and-relay )

May be surfing on the parts catalog (with your VIN) may help locating parts : http://europe.toylexparts.com/aygo/101510/kgb10l-agggkw/526w/001/4/8401

Also i found in my archives this thread without warranty having a diagram discussing BF01 and content (while mismatch with assignment R3 or R4 ...)  this may give some clues to test few checkpoints ?

 

[Cribus]

Wow those ideas and links are really useful, thanks!  Looking at my car I can see that the fusebox is in two parts, held together by clips, so I need to get it out of the confined space and split it, and see what's inside.  I will update as soon as I have done that.  Thanks again!    

[flash22]

The relays are solid state they either work or they don't i would replace the pump first given the symptoms, you may find hitting the fuel pump brings it back to life

if you run the tank low/dry too often you will burn a pump out, try and leave 1/4 of a tank in the car as the fuel cools the pump

i take it you have fuel in the car and not misfuelled it with diesel by mistake

[Cribus]

Thanks for that, yes it's definitely petrol in the car rather than diesel and there's plenty in the tank.  I don't tend to run it low, I get restless by the time it gets down to 1/4 tank!  

Splitting the fuse box is proving really difficult on my car without breaking the clips off, and without doing that there is just no sign of the relays shown in the photo.  They must really be hidden down in the body of it somewhere.  So I may well try the pump first.  I tried thumping it but no joy.

Hoping to have another look at the weekend, I'll update once I have progress.  Thanks again.   

 

[Zakk E.]

Hi, I am also experiencing issues with my aygo(2006) it started running roughly, misfiring and eventually it doesn’t start up. It cranks but the fuel pump does not activate. I measured the voltage going to the fuel pump when the ignition is turned on and got nothing. I tried feeding electricity directly into the fuel pump and sure enough it gives off a low buzzing sound. So I have concluded that there might be a problem with the relay. I cannot however get to it and am wondering if anyone here knows how to get to it, test it and replace it.

[dee c]

Hi I'm I've been having a rattle under the car but not the exhaust... last week the car wouldn't start but changed the plugs and its working again. Could the rattle/ popping be the fuel pump?

[Ste123]

Hi all 

Did any one find were the realys are has trying to find them my self with no luck thanks steven

[flash22]

4 hours ago, tsikis007 said:

There is no relay at least in the first generation. 

That is incorrect, the fuel pump relay is an internal solid state relay built in to the main fuse box as pictured above

if you have a crank no start check that you have spark, if not It's likely to be an immobilizer issue

[KristianLarsen]

Double post!

 

Edited October 19 by KristianLarsen
Double post

[KristianLarsen]

Hi @Cribus

Did you find a solution to your problem?

Im in the same situration. Lots of crank and spark but no power to the fuelpump

[flash22]

Start with the basics supply to the pump, check for 12v using a body ground

try starting the car with a spare key, if you have done anything with the fob make sure the chip is still is in the case

check fuses under the bonnet and the ones in the car (on the sides of the speedo)

one of many vids on youtube

 

[KristianLarsen]

55 minutes ago, flash22 said:

Start with the basics supply to the pump, check for 12v using a body ground

try starting the car with a spare key, if you have done anything with the fob make sure the chip is still is in the case

check fuses under the bonnet and the ones in the car (on the sides of the speedo)

one of many vids on youtube

 

Hey and thanks for the quick reply.

The pump relay dosent send out 12v. If i send 12v to the plus manualy the pump runs. The main ecu-relay are also off.

what can cause the ecu not to set the MREL signal?

[KristianLarsen]

27 minutes ago, KristianLubikn said:

Hey and thanks for the quick reply.

The pump relay dosent send out 12v. If i send 12v to the plus manualy the pump runs. The main ecu-relay are also off.

what can cause the ecu not to set the MREL signal?

All fuses are OK and unfortunatly i dont have a spare key.

[flash22]

Do you have voltage at the injectors (ground side ecu switched)

Has the car been jump started ?

I would be checking this 120a ALT fuse

 

[KristianLarsen]

2 hours ago, flash22 said:

Do you have voltage at the injectors (ground side ecu switched)

Has the car been jump started ?

I would be checking this 120a ALT fuse

 

Hey and thanks for the reply!

the fuse is okay (what a pain to get to 🙈) Injectors are working. The motor ran when I manually powered the fuel pump!

[flash22]

with the relay where did you check for power at the pump only or at the connector

what you need to know is, are you getting power to the fuel pump relay and do you have power and ecu control (ground side switch)

[flash22]

go back over the fuses and find IG2 15a on the side of the speedo, then remove the fuse, clean and check the terminals, change the fuse

[KristianLarsen]

12 minutes ago, flash22 said:

with the relay where did you check for power at the pump only or at the connector

what you need to know is, are you getting power to the fuel pump relay and do you have power and ecu control (ground side switch)

I checked at the relay output - the pump relay is feed through the main ecu relay which is off as well. The ecu are not giving 0v/ground to the ecu relay which make me think there are another sensor interfering?

[KristianLarsen]

21 minutes ago, flash22 said:

go back over the fuses and find IG2 15a on the side of the speedo, then remove the fuse, clean and check the terminals, change the fuse

Will do! What are this fuse for?

unfortunately I can not access the car today - I will check tomorrow evening!

[flash22]

we need to check the control side of C/OPN (fuel pump relay) this is fed from IG2 to pin 1 (1D) with the ignition on you can also check it at the BA1 plug pin 4

 

Also, unplug BA1 and inspect the plug and socket (top of the fuse box next to the fuses, 10-pin white connector)

[KristianLarsen]

Hi again. 
 

I was wrong regarding the injectors. They are also dead. 
The ECU are putting out 12v on the MREL output. 
is there a way to check if the immobilizer is the problem?

The pins in the BA1 looks fine 🫤

[flash22]

check the earth  front left on the cylinder head (brown and white with black wires)

have you scanned it for codes? has the fob been apart for any reason? try pushing up as you turn the key

[KristianLarsen]

2 hours ago, flash22 said:

check the earth  front left on the cylinder head (brown and white with black wires)

have you scanned it for codes? has the fob been apart for any reason? try pushing up as you turn the key

Hi again - thanks for all the help!

i tried to ground the MREL wire and everything is running as it should. 
Can the transistor controlling the MREL output be fried?

All earth points are checked and ok!

[flash22]

so the ecu does not have control that could be the immobilizer or wiring issue, check it at the ecu (ground side switch) when the car is cranked, check the continuity between ECU and BA1

Pull any codes with a scan tool, if not you can do a flash test

Link the 2 pins shown, turn the ignition on and count the flashes of the MIL/EML light on the dash