TB45 ECU/Fuel Pump Signal Issue

[51KGU]

Hey guys. Just yesterday my car decided not to start.

I’ve worked out it’s ECU to Fuel pump relay related.
Does anyone have a wiring diagram for a TB45 so I can figure what wires go where and fix a potential issue before I replace and destroy another ECU lol.

Thanks!

[jff45]

The only wire between ECU and the fuel pump relay is the earth for the relay. When you first turn ignition on, the ECU earths the relay ONLY for 5 seconds (it restarts the pump after it gets a signal that the engine has started).
If that doesn't happen, check the relay first. It's one of the 3 blue relays just above the fuses in the RH side fuse panel. You can swap them over to test.

[51KGU]

I see!

I tried swapping them over, it did the same thing. It’s before the relay, whether it’s ECU or power input for the relay.

What would happen is you’d turn the key to IGN and the relay would buzz and carry on erratically with no start of the engine.

I took power from the window relay plug and put it to the fuel pump plug and the pump came on and the car started.

I have no engine light, so would you suggest I look for a short in the loom that brings power to the relay, rather than the ECU?

[51KGU]

Also, the relay in question is on the passenger side kick panel.

[51KGU]

74628 this was my temp fix to get home

[jff45]

Fuse for the relay is ok?

It’s very easy from the relay socket to test if the ECU is earthing the relay. Also easy in the same socket to test if the relay is getting power.

[51KGU]

The relay is not getting power.

That’s why I’m after a wiring diagram so I can figure out which wires go where.

Anyone!?

[jff45]

I don't think your fuel pump relay is over on the passenger side. From memory, power windows and horn relay are there.
The fuel pump relay on a TB45E is above the fuse panel on the RH side. I think it's the top left relay.

The 15A fuse in the panel is clearly marked. If it has power from ignition, it's easy to check if the wire to the relay from there is intact.

[51KGU]

It’s definitely on the passenger side. When I put power to that wire, the fuel pump runs and I can drive the car.

[51KGU]

Fuse is fine, yep.

[51KGU]

So I fixed it.

For some reason the previous owner had replaced a section of wire on the fuel pump relay circuit and did the old twist and tape... the connection was poor and corrosion eventually made that connection fail.

Found it, fixed it and she runs like a dream again!

Thanks homies