1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

LR4 suddenly won't start/crank. Even with fully charged battery and/or jump

Discussion in 'LR4' started by pbsmi, Jul 5, 2020.

  1. pbsmi

    pbsmi New Member

    Age:
    49
    Posts:
    4
    Likes Received:
    2
    Joined:
    Jul 5, 2020
    Location:
    Louisiana
    My instrument cluster now looks like normal. I had to reset the time and the date, but that's about it so far that I have noticed. I guess the LR4 computer does some weird stuff when it has low voltage.

    The SM relay from what I can gather stands for "Starter Motor" or Start Motor (please know, all I know is what I have read on forums) and can get stuck in the closed position, where it did in my case, draining the bad battery to the point where it can't get jumped. Other than this, I am still learning. But yes, in my case, I had to completely disconnect this relay and reset it (pull it out/then push back in) prior to putting in the new battery.
     
  2. gsxr

    gsxr Full Access Member

    Posts:
    401
    Likes Received:
    149
    Joined:
    May 8, 2017
    Location:
    Idaho
    Phil, sorry I didn't see this sooner. If a fully charged good battery were to have voltage drop below 10V, the load would have to be something over 400A, and you would have had a massive fireworks display when you tried connecting the terminals.

    What likely happened was a shorted cell, which will show good/charged (12.6V+) with no load or even light load, but when a larger load is applied (i.e., trying to start the engine), fuhgeddaboudit... voltage drops through the floor, until the load is removed, then it reads fully charged again. I've experienced this several times over the past ~15 years, mostly with Interestate batteries (which I no longer buy).

    The LR4 may have some sort of safety mechanism where it doesn't even try to engage the starter below a certain voltage. The only mystery is why the jump-start didn't work... in theory, that SHOULD have fired up the engine and gotten you home. Again, it's possible something had to be reset.

    I don't know the purpose of the SM relay, or how it functions in non-standard situations. Sounds like something good to learn though.

    :albertein
     
  3. ElChuco

    ElChuco Member

    Age:
    57
    Posts:
    16
    Likes Received:
    2
    Joined:
    Jan 15, 2017
    Location:
    El Paso
    I had a similar problem where my LR4 with a brand new battery would not crank, not even a click. The manual describes a procedure which I tried, and it worked. I don't understand what my problem was, nor why this procedure worked, but it did. It goes basically like this: very slowly depress gas pedal to the floor; hold pedal to floor and hit the "Start" button; release gas pedal to return it to upright. I have used this procedure, of necessity, about 3 or 4 times through the last 5 years, and it works every time to start the engine when I'm not getting any crank at all. I would love to hear an explanation from anyone.
     
  4. cperez

    cperez Full Access Member

    Posts:
    1,410
    Likes Received:
    515
    Joined:
    Mar 3, 2014
    Location:
    Bethesda, Maryland, USA
    That sounds quintessentially Land Rover-ish. There is no further explanation than that.
     
  5. Jasevo3rs

    Jasevo3rs Active Member

    Age:
    49
    Posts:
    27
    Likes Received:
    5
    Joined:
    Jun 25, 2020
    Location:
    Houston, TX
    I'm guessing you still need to depress the brake pedal at the same time?

    Is this 'trick' in the owners manual or workshop manual?

    I'm kind of having a similar issue at the moment but I am getting an audible 'click' when pressing the start button. Replaced the battery with a new H8 AGM unit which must have been on the shelf for a little while as was at 12.4v. LR wouldn't start so gave her a jump and after a couple of attempts she fired up. Just took her for a good drive to get the new battery charged up and just leaving her be for a little while.

    Stupid question number one - Does the drivers door need to be closed to start? Reason I ask is that when I was jump starting she would only 'click', I then closed the drivers door and voila she kicked over!?

    Sorry to hijack the post but similar theme.
     
  6. Quijote

    Quijote Full Access Member

    Posts:
    1,114
    Likes Received:
    227
    Joined:
    Feb 16, 2013
    Location:
    Metro Boston
    Could this be a way to skirt the need to "program" a new battery? Has anyone installed a new battery without any sort of programming and had no trouble at all?
     
  7. CelsioR30

    CelsioR30 New Member

    Age:
    42
    Posts:
    1
    Likes Received:
    1
    Joined:
    Jun 17, 2020
    Location:
    Hawaii
    Aloha newbie here on the forums. I just saw this posted!

    I have similar problem with my LR4 before won’t crank won’t start. I purchased brand new battery still won’t start. I ended up replacing my alternator still won’t start. I found out, I was playing around with the brake pedal at the same time pressing start button finally car fired up. I believed all Range Rover has this features, if we don’t know how to trouble shoot then we will ended up taking our car to the dealership and charge us arm and leg for a simple fix. So far no issues here.

    TRY DO THIS ON YOUR CAR:
    press or hold brake pedal while starting your car, pump it TWICE on your brake pedal and hopefully this will resolve your problem.

    HOPEFULLY THIS WORKS!

    GOOD LUCK...!
     
    Jasevo3rs likes this.
  8. Jasevo3rs

    Jasevo3rs Active Member

    Age:
    49
    Posts:
    27
    Likes Received:
    5
    Joined:
    Jun 25, 2020
    Location:
    Houston, TX
    Aloha

    Ahhhh.... come to think of it, I did notice that yesterday. Whilst attempting different things, I did at one point notice that the brake pedal was 'squishy' and went to the floor with some but not the normal resistance. Same kind of feeling as when there's air in the brake lines - for the record have not had any issues with the brakes. This was whilst I was trying the accelerator trick suggested by ElChuco in a previous reply.

    She actually started up OK this morning four times in a row... but considering the issues of yesterday, I'm not yet game to take her our out and switch her off. If she reverts back to not starting, I'll try the brake pedal as you have suggested.

    Appreciate the suggestion!
     
  9. Lgibson

    Lgibson Full Access Member

    Posts:
    266
    Likes Received:
    10
    Joined:
    Dec 25, 2014
    Sounds a lot like a faulty brake switch to me. My Touareg won’t even shift out of park with a bad brake switch.
     
  10. JKJK

    JKJK New Member

    Age:
    54
    Posts:
    3
    Likes Received:
    0
    Joined:
    Sep 4, 2019
    Location:
    Chicago
    Agreed. I keep a spare brake light switch in the car just in case. Not an expensive part to carry.
     

Share This Page