U0100 code (edited title)

[PoorLifeDecisions]

Do you guys know what the proper (negative) battery terminal connections are supposed to look like? The original positioning seems off and the negative terminal didn't seem like it was getting a tight connection. I've moved it around a little already. There seems to be a notch where the main steel part can sit up against the battery, but there doesn't seem to be anyway to position it so it can line up there.

My dash lit up and went into limp mode. Pulled over rested and restarted and it went back to normal. I'm at Sepulvida LA Costco now and I'm trying to connect a new battery. Trying to get back on the road for my stay at Pismo Beach on the way back to NorCal.

 

[jlglr4]

That looks like mine.

 

[PoorLifeDecisions]

Thanks for the quick reply! I positioned mine that way, but can't seem to get it down as low to post as yours. This is the lowest I can get it.

 

[jlglr4]

That should not make any difference. Looks like plenty of contact for a solid connection. Are you still having issues? Do you have a scanner? Sometimes a code gets thrown that needs to be reset. If you don’t have one, you could see if the costco auto center guys have one you could borrow. Or maybe there is a auto parts store nearby.

 

[jlglr4]

I guess the other thing: are you sure the limp mode was due to a bad battery?

 

[PoorLifeDecisions]

I'm thinking/hoping the limp mode was just due to loose negative connection. I did a hard reset awhile back and I don't think I tightened it enough, or week enough as I just did now.

Tried running scanner after the first limp mode and got U0100

 

[PoorLifeDecisions]

Crap, check engine light is still on. Still code U0100 Lost communication with ECM/PCM "A"

 

[jlglr4]

I assume you tried clearing the code and it just comes back right?

 

[jlglr4]

Gonna be out of pocket here for a while. Hopefully someone else can chime in.

Just a couple of thoughts in the meantime: U0100 is a com code - which usually means an electrical problem - at least in my experience. Something is not getting power. Check brake switch (brake lights working), check fuses and relays, check the passenger side carpet for water intrusion - maybe look for corrosion on those fuse boxes.

 

[PoorLifeDecisions]

Yeah tried clearing it. It's permanent.

Sucks but had to cancel our bookings and stay nearby until Land Rover Encino opens on Monday and hopefully can squeeze me in. I'm going to check the switches and fuses tomorrow. The truck had a passenger side sunroof drain leak when I got it a few months ago and there was water pooling under the front carpet. When I was cleaning it up I didn't notice corrosion, but I didn't do an in depth examination either. That area has been bone dry though ever since then. If it is something there, don't know why it would start acting up now.