P500 Electrical issue

[aauman88]

I have a 500 that we are rebuilding and can’t get it to run now. The third fuse down on right side has no power and the dash doesn’t light up. Can jump power to the fuse and dash lights up. The four relays also power on when power is jumped to the fuse. Turns over but no fire and don’t think the fuel pump comes on either.

Question is does the ecu power that fuse or does that fuse power the ecu? I have a PV3 and the diagnostic port under hood does not have any power at any time. I believe the ecu is bad but I could be on wrong path. New ecu won’t be here until next week so seeing what someone else thinks.

Thanks in advance

 

[HondaTech]

Do you have the fuse box lid to narrow down which fuse your having issues with?

Also what year?

 

[aauman88]

2017 and the lid was missing when I bought it. I have one on order with the ecu 🤷🏻‍♂️

 

[HondaTech]

Dang, we don't have a 500 at work to reference either.
There's only one row of fuses on a 500, right? Besides the spares?

None of the fuses are controlled by the ecm.

Maybe pull the box and look which color wire is coming from the fuse your having issues with.

 

[Hondasxs]

looking at 2015 info...
3rd fuse is the fuel pump relay.
It gets its power from the 40A main fuse.
40A main fuse is connected directly to the battery.
Both should be all the time hot.

 

[Hondasxs]

@HondaTech, where is the 40A main fuse on a 500?
Probably close to the battery in a gray small fusebox. If not inside the battery box.

 

[aauman88]

Yeah it’s in-line about 6” from battery. But if it was bad would it even be trying to crank ?

 

[Hondasxs]

Yeah it’s in-line about 6” from battery. But if it was bad would it even be trying to crank ?

Not so sure..
Tracking it... It looks as if the 30A #1 fuse handles the ign process.
#1, 30A is also direct to the battery.

 

[aauman88]

I ruled it out and didn’t even check it 🤦🏻‍♂️ Let me check it first thing in am.

 

[Hondasxs]

I ruled it out and didn’t even check it 🤦🏻‍♂️ Let me check it first thing in am.

Kool....
That's most likely your problem.

 

[aauman88]

Alright went and checked. The 40a is good. The fuse in question is the 3rd down on right side, 30a. All other fuses are good and have power, that fuse is good but no power to it.

 

[aauman88]

If I jump power to it the dash lights up and here relays energize but still won’t fire. It’s like a safety has it out.

 

[Hondasxs]

Just got in the bed.
But i will send you the wire diagram tomorrow.

Again this is 2015.
You can see the fuel pump relay fuse gets its power from the 40a.
If the 40a has power the fan and fuel pump should too.

 

[aauman88]

Awesome, thanks

 

[DG Rider]

The only 30a shows to be "ES". It's fed from a separate feed from the battery (not the 40a main).

 

[HondaTech]

Alright went and checked. The 40a is good. The fuse in question is the 3rd down on right side, 30a. All other fuses are good and have power, that fuse is good but no power to it.

View attachment 249734 View attachment 249735

Which fuse in this picture is no powered?
The wiring diagram is upside down i believe, because the 30 amp fuse off to the bottom should be the main. The 3 holes on the left are spares holes.

If you follow the wiring diagram fuse count, the 3rd fuse from the top is actually the light fuse. Anybody with a P500 care to grab thr fuse box lid and look.

 

[aauman88]

Third one down from top on right. 30a green fuse

 

[Hondasxs]

Sent you a email.

 

[aauman88]

Sent you a email.

Thanks

 

[aauman88]

The layout on that diagram is different I guess from mine being 2017. The Inj/Ign fuse is fed with black wire with white stripe from the PCM. That’s the fuse I don’t have power on. So it’s looking like it is the PCM bad unless there is some trick when hooking up the PCM?? My buddy said unhook it and battery and hook PCM up first then followed by battery. Will try it later but don’t see it helping