I have a parasitic drain.
I have narrowed it down to the engine compartment fuse panel - 20 amp JTEC / Fuel Pump fuse. If I pull fuse drain goes away.
This appears to send power through the engine harness to the PCM. If I disconnect the main engine harness at the engine fuse panel - Drain goes away.
If I disconnect the PCM connector 1 - drain goes away.
Hence - Is the PCM supposed to be powered on when key is off?
If not, I will look at an ignition key issue.
TIA
Nick

 

Which engine?

PCM should still have power even with key off. It should be a really minor drain though, a few milliamps.

 

4.7
I am not sure if I have a way to check draw. I will try today.
Thanks
Nick

 

So fun. The truck battery has been disconnected for a few days. Reconnecting it, I could not replicate the problem I had before of draw coming from the PCM.
I connected the battery, it shows 12.14 volts. (This is the third battery in three months). I started it up. It starts and runs fine. Again, I could not find the high power connection associated with the PCM.

Looking at my digital amp meter, I am pretty sure I was able to get a amp reading. My digital meter only goes to 10 amps.
With key on, it seems to go to 8.8 amps. With key off, it drops to 0.2, then spikes to 0.8 and almost immediately drops to 0.2.
Back to my previous testing of the PCM seems and it no longer seems to draw as much power as before. UGH. I am sure this will come up again.

 

Battery voltage seems a bit low for one that was disconnected.....

How is your charging system?

 

Yes, this battery had died, I put it on a charger for a few days. I’ve disconnected the battery.
the alternator and regulator was off the truck and bench tested good.
I do get 14 volts when idling. I haven’t driven it for a while now.
This battery may very well be bad now. I still have the warranty. Just need to bring it in to test and replace if needed. I still want to find the drain first.

 

Get an accurate measurement of just how much of a drain you have.

 

what I posted earlier is not accurate?
how do I get an accurate measurement?
thanks

 

If your draw really is .2 amps with everything off, I think that is within the 'normal' range. Just make sure no bulbs are staying on. Glove box, ash tray, underhood lamp..... Easiest to see when its dark out.