n75 wgfv.

[Kieron20V]

The other pin should be a pulsed ground from the ecu when triggered.

[Monkeymagic]

So how do we trigger it? Basically it reads 23 volts which is clearly not correct. I suspect it was the volt meter just giving a random reading.
The n75 certainly clicks when the ignition is cycled but does nowt on output tests.

[Kieron20V]

Run the output test with the meter hooked up. But as you said it doesn't click so it doesn't like like the ecu is triggering properly. I'd clean up all the ground the ecu uses on the pinout, and check resistance from the ecu plug to ground, sounds like either a stray ground somewhere or something internal like the driver inside ecu.

[Monkeymagic]

Many thanks ill have a look. Seems like something isnt triggering as it clicks with ignition on and off.

[Error404]

AS above, pretty sure the ECU pulls to ground to actuate the N75. It goes to pin 33.
Have you checked state of that pointless white 2 pin connector that the mini harness for the N75 plugs into? Could well be crusty in there

[Human Joist]

Checked the harness and it seemed ok. Ground hunting then

[Error404]

You have continuity between pin 2 at the N75 and pin 33 at the ECU?

[UrS4boy]

You have continuity between pin 2 at the N75 and pin 33 at the ECU?

Agree regarding checking and confirming this.

The N75 is powered through the J17 fuel pump relay so checking for power can only be done with the engine running, stopped = nothing. With the engine running, there should be 12V power coming in on a red wire and continuity for the other wire (yellow/red stripe for an AAN) that the ECU uses to pulse the power through the N75 by taking it to ground, through the ECU (pin T55/33).

[Monkeymagic]

I have to confess to having little auto spark knowledge. Contnuity presumably select the correct setting on voltmeter a qire extesion then plug into terminal 33 and number 2 and you should get a buzz??
What is interesting is that yhere is a relay in the door pocket relay 31 which i thought qas for the cooling fan. Coild the fuel pump relay be suspect?

[Monkeymagic]

Sorry for all the typos

[Error404]

Set your meter to the continuity setting, symbol looks like this:



Then probe each end of the circuit, it will beep or display to tell you they are connected

[Monkeymagic]

Sweet cheers alex....

[Human Joist]

Right. Continuity checked and I have it between pin 33 and pin 2 the yellow green wire.

So two things, what's next to check and which git failed to mention how joyous it is to remove the ecu.

[Monkeymagic]

Jim my apologies if you've tried contacting me Lily has knackered my phone. I'm no expert in auto levy but I would suspect grounds or is it possible looking at wiring diagram it's the fuel pump relay sticking hence why it randomly clicks? Purely guess work though bud.

[Monkeymagic]

Mind you saying that if that we're the case wouldn't the isv and evap fail to function too?