'18 JLUR 2.0T Dead Battery, Jump Start starts engine with stutter and minimal power.

jerrygcoffey · Oct 14, 2023

Started packing for the camping trip at 6am. Went to start at 9am to find my screens flashing and gauge needles twitching. Got a jump start only to hear a pitiful puttering noise from the exhaust and barely enough power to move on a flat city street.

I'm thinking alternator, but unsure. Does this sound familiar? Awaiting tow to dealer. 56K miles. Extended Warranty.

mwilk012 · Oct 14, 2023

‘18 with a 2.0 is the Etorque variant. Your alternator doesn’t produce 12v, it’s the 48v MGU. Your battery is bad.

jerrygcoffey · Oct 15, 2023

mwilk012 said:
‘18 with a 2.0 is the Etorque variant. Your alternator doesn’t produce 12v, it’s the 48v MGU. Your battery is bad.

Damn. Well I have a relatively small deductible on the extended warranty for this reason. My concern now is if the 48v battery generally has a 50-60k miles lifespan, the next time it happens I’ll be SOL.

captainstabbins · Oct 16, 2023

I tthink the 48 volt battery has an 8 year warranty along with the alternator.

mwilk012 · Oct 16, 2023

jerrygcoffey said:
Damn. Well I have a relatively small deductible on the extended warranty for this reason. My concern now is if the 48v battery generally has a 50-60k miles lifespan, the next time it happens I’ll be SOL.

I’m sorry if you misunderstood. Your 12v battery is bad, and your warranty will cover nothing.

jerrygcoffey · Oct 16, 2023

mwilk012 said:
I’m sorry if you misunderstood. Your 12v battery is bad, and your warranty will cover nothing.

Would a bad battery explain the absence of power when actually started? I'm talking less engine power than limp mode. Could barely move the weight of the jeep on a flat surface with the pedal to the floor.

Bob Burd · Oct 18, 2023

What does the battery voltage read when it is running in sub-limp mode?

alphawolff · Oct 19, 2023

jerrygcoffey said:
Would a bad battery explain the absence of power when actually started? I'm talking less engine power than limp mode. Could barely move the weight of the jeep on a flat surface with the pedal to the floor.

A bad 12v battery will cause all kinds of weird shit to happen. A fully flat 12v will prevent event a normal 12v system from properly charging with the alternator. Replace it and it'll be fine.