I was driving down the road, recording some datalogs(second day I've had the thing...) all of the sudden, the CEL came on and the engine died. The connection was lost to the computer, and it won't come back online like it should in Smanager.

I've checked all of the fuses, they're fine.

I swapped my stock p28 back in- still no start, still CEL on, also, the fuel pump doesn't sound like its coming on.

I have yet to check the power directly to the ecu. That's about my only idea. Couldn't be a bad ecu, because I've tried two.

Any thoughts? If the ecu is getting power it should at least come online I would think.

Jake

 

Anybody know which pin the ecu is powered by? Maybe A25?

 

Check your ecu fuse under the hood and the main relay

 

Does your main relay power up (fuel pump priming)?

ECU will also go solid cell when it looses ground.
Stock ground location is at the thermostat housing and is shared with sensor grounds as well as the main relay ground.

 

That could be it! The fuel pump does not prime.

There is no power at the IGN1 or 2.

When I test for continuity from the fuse to the ecu, I get nothing.

When I test continuity from the fuse to the other side of the engine bay( where the yellow/blk wire connects to injectors), The multimeter goes backwards... I'm guessing that's because of the relay? Any explanation on that would be grand...

I'll check the ground when I get home.

 

So! I found the problem. The main relay was not receiving power from the ignition with the key on. Fuse 14 under the dash (10 amp) was blown. The fuse is for the alternator solenoid; I'm not sure why it went, but the car is running fine again with no codes.

Hope this helps someone! To sum it up, the ecu lost power suddenly because the main relay shut off and the CEL came on solid.

 

i kinda knew it was that fuse too it has happend to me i would check for opens on the alternator cable or loose grounds

 

If it blows again don't just keep filling in new fuses. Check it out.