2020 Defender Talk about the new 2020 Land Rover Defender
Sponsored by:
Sponsored by:

Well, it won’t start - p300 4 cyl

Old Nov 2, 2025 | 08:40 AM
  #1  
Bigarch's Avatar
Thread Starter
|
5th Gear
Joined: Sep 2023
Posts: 5
Likes: 1
Default Well, it won’t start - p300 4 cyl

When I hit the start stop button, only the infotainment system comes on. Nothing populates on the dash, nothing.

I tried to jump it with my wife’s car. Then with a battery pack jumpstart thing from AAA. Nothing.

key fob works and locks and unlocks the car.

is it the battery? If so the one under the passenger seat or the one under the rear luggage compartment.

or a different issue entirely? Any help is appreciated!

Car details. 2021 Defender 110 P300 4-cyl 45000 miles.
 
Reply
Old Nov 2, 2025 | 10:17 AM
  #2  
RH5555's Avatar
Mudding
Joined: Nov 2021
Posts: 133
Likes: 85
From: Friday Harbor WA
Default

I'd try disconnecting the battery, wait ten minutes, then reconnect. Force a complete reboot...
 
Reply
Old Nov 3, 2025 | 07:22 AM
  #3  
sarek's Avatar
Rock Crawling
Joined: Dec 2021
Posts: 466
Likes: 842
From: Richmond, VA
Default

Put the key under the column and try to start it
 
Reply
Old Nov 3, 2025 | 08:04 AM
  #4  
Bigarch's Avatar
Thread Starter
|
5th Gear
Joined: Sep 2023
Posts: 5
Likes: 1
Default Ok that worked.

So I pulled the negative cable off the battery for 10 mins and put it back and it started right up. The ECU needed a hard reset. I’d recommend keeping a spanner 10mm, in your tool kit int the back.

I also attempted, miserably, to change the battery myself. I got the seat disconnected and off but couldn’t get the actual battery out. So it’s in the shop today. $800.
 
Reply
Old Nov 3, 2025 | 08:54 AM
  #5  
SilverSFR's Avatar
Rock Crawling
Joined: Apr 2006
Posts: 252
Likes: 140
From: Boise, Idaho USA
Default

I am curious as to what part of the battery removal you had trouble with? You mentioned that you have the seat disconnected and off/out of the vehicle? Was it the weight or angle of the battery?
 

Last edited by SilverSFR; Nov 3, 2025 at 09:04 AM.
Reply
Old Nov 3, 2025 | 09:23 AM
  #6  
Bigarch's Avatar
Thread Starter
|
5th Gear
Joined: Sep 2023
Posts: 5
Likes: 1
Default

Originally Posted by SilverSFR
I am curious as to what part of the battery removal you had trouble with? You mentioned that you have the seat disconnected and off/out of the vehicle? Was it the weight or angle of the battery?
it just wouldn’t move. It was connected somehow to a housing that I couldn’t see.

the other issue was the reset of the computer. I don’t have a gap tool; which I’m thinking I need but they are pretty pricey.
 
Reply
Old Nov 3, 2025 | 11:03 AM
  #7  
RH5555's Avatar
Mudding
Joined: Nov 2021
Posts: 133
Likes: 85
From: Friday Harbor WA
Default

Just had my battery replaced by dealer. Only $528 including tax. I was pleasantly surprised.
 
Reply
Old Nov 3, 2025 | 12:01 PM
  #8  
Bigarch's Avatar
Thread Starter
|
5th Gear
Joined: Sep 2023
Posts: 5
Likes: 1
Default

Originally Posted by RH5555
Just had my battery replaced by dealer. Only $528 including tax. I was pleasantly surprised.
I was $825 out the door but there was a loose wire that needed to be repinned that they charged me another .5 hrs of labor.

not great. Not the end of the world.
 
Reply
Old Nov 3, 2025 | 01:02 PM
  #9  
Juancl's Avatar
Rock Crawling
Joined: Sep 2017
Posts: 375
Likes: 173
From: South Florida
Default

P300 D90 with 47,500 miles. Back in May I left my car at the dealer for a "final month of warranty" thorough inspection (had them check every little thing for potential issues). Can't be happier with my SA, last service before warranty expiration included new battery, new coolant system hoses and expansion tank and new front wheel bearings.

When did your warranty expire? It’s not unheard of that with a bit of pushing to JLR they might cover repairs that come up right after warranty expires (it's not guaranteed, but it doesn't hurt to ask if the failure came close after warranty expiration).
 

Last edited by Juancl; Nov 3, 2025 at 07:21 PM.
Reply
Old Nov 4, 2025 | 10:28 AM
  #10  
DoctorofRocks's Avatar
Rock Crawling
Joined: Mar 2021
Posts: 342
Likes: 256
Default

I tried to do that as well - but they weren't interested. Had previously been happy with Jake Kaplan Land Rover in Warwick, RI but skipping that request and forgetting to reset the "change oil soon" warning after charging me over $1000 for a 42k service has left me questioning what else they "forgot" to do.

Did you pay them for their time to do this inspection?
 
Reply

Thread Tools
Search this Thread

All times are GMT -5. The time now is 11:09 AM.