55k mile Yukon won't start

[gucci88]

Hi all

I have a 2009 Yukon Hybrid with 55k miles which is currently having a no start situation after I left it in the garage for 2 months. It started once 2 days ago and hasn't started since. Hybrid and BECM are currently putting out a P0B3D Hybrid battery 1 circuit low voltage. I have uploaded photos below of the error codes and the live data from the hybrid module. What can I do to solve this no start situation?

 

[swathdiver]

Is the 12 volt battery in good condition and charged up? That ought to get the truck started and with it even idling the under seat battery pack ought to begin getting recharged.

@RebelBelle What do you think Gene?

 

[gucci88]

Is the 12 volt battery in good condition and charged up? That ought to get the truck started and with it even idling the under seat battery pack ought to begin getting recharged.

@RebelBelle What do you think Gene?

The 12v battery is new. I thought that might be the issue so its the one I replaced first. It started once after the 12v battery change and hasn't started since.

 

[swathdiver]

The 12v battery is new. I thought that might be the issue so its the one I replaced first. It started once after the 12v battery change and hasn't started since.

New doesn't necessarily mean it's charged up. It might have had enough juice to start the first time and not enough to do it again. Check it's voltage with your multimeter.

 

[gucci88]

New doesn't necessarily mean it's charged up. It might have had enough juice to start the first time and not enough to do it again. Check it's voltage with your multimeter.

Its reading 12.7v

 

[j91z28d1]

there's no 12v starter on this truck. only thing that spins the engine over to start it is the hybrid battery using the front motor in the tranny. but to close the relays to engage the hybrid battery it's gotta pass a bunch of tests too. it needs a decently charged hybrid battery to complete all of it before it even attempt to spin the engine over.

you need to use jump assist mode. a scanner is needed to activate that mode. once in it follow the tsb or the on screen scanner directions. it puts the under hood inverter into a modebthat will allow it to charger the 300v hybrid battery off the 12v system. you'll need a charger hooked up.

it takes a while to get charged up. few hours on a 20amp charger I believe it is.


check your owners manual, it will give recommendations for how to store these trucks so they don't kill the battery.

 

[gucci88]

there's no 12v starter on this truck. only thing that spins the engine over to start it is the hybrid battery using the front motor in the tranny. but to close the relays to engage the hybrid battery it's gotta pass a bunch of tests too. it needs a decently charged hybrid battery to complete all of it before it even attempt to spin the engine over.

you need to use jump assist mode. a scanner is needed to activate that mode. once in it follow the tsb or the on screen scanner directions. it puts the under hood inverter into a modebthat will allow it to charger the 300v hybrid battery off the 12v system. you'll need a charger hooked up.

it takes a while to get charged up. few hours on a 20amp charger I believe it is.


check your owners manual, it will give recommendations for how to store these trucks so they don't kill the battery.

Thank you for your reply. I have tried to use jump assist mode before and I will re activate it to charge the hybrid battery. I'm just ginna have to find a 20 amp charger as I only have a ctek 5 amp.