Toyota Prado 120 battery draining

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  1. #1
    Join Date
    Aug 2011
    Thanked: 0

    Default Toyota Prado 120 battery draining

    My Prado's battery goes flat if I leave her standing for 3-4 days. I have checked with the tracking companies and she has an old netstar unit installed,(I'm using Cartrack) and that I believe could be pulling power, any other things that could cause the power draw?

    Toyota Prado 120 4.0lVX
    Mitsubishi Pajero 3500 -broken motor
    Isuzu Frontier 2.8 - scrapped
    Isuzu KB280 double cab - sold

  2. #2
    Join Date
    Oct 2017
    Thanked: 41

    Default Re: Toyota Prado 120 battery draining

    I had the same problem with my Corolla. Bought it second hand. It was draining the battery overnight.

    Took it to the auto electrician and we found a tracker unit that had a flat battery. So over night it was braining the car battery.

    My bet it try and locate the tracker unit. These tracking companies usually install 2 units on a Toyota.... Hight risk, I was told.

    Hope you come right

  3. #3
    Join Date
    Dec 2016
    Thanked: 130

    Default Re: Toyota Prado 120 battery draining

    Suggest you do a parasitic draw down test via the battery to check rate of draw, then take out fuses one by one to see what or where it is, comparing to the fuse diagram and the vehicle intruction book. This may show other fault or the possible location of the Tracker, if it is this. Need to start with a charged battery. Google it as there are videos of how to - look at one or two. My 2c

    How to perform a parasitic draw test
    20A – 200 mA (should have 50mA or less)

    • Sort battery charge (Test must be full). Should be 12.6V settled.
    • Open bonnet.
    • Close door, key out etc. i.e. calm ECU/computer.
    • Allow to settle.
    • Use negative pole.
    • Disconnect negative pole.
    • 20A scale best 50mA or less.
    • +/- 200mA indicates a problem.
    • What to do:
    o Pull external fuses one by one till a fuse results in a drop (Note replace them well and firmly after each one is out - take note of position of each and identify each
    off the instruction book).
    o Record/identify fuse as u go.
    o Check circuit (could be leak to earth etc.)
    o If you need to work i/s vehicle disconnect the amp meter first, the one used in the external process - NB. Then do same process. Disable the door light button -
    some clamp it “closed”. Again allow the ECU to calm down to inactive state.

    The car keys should be well away from vehicle preferably

  4. #4
    Join Date
    May 2014
    Thanked: 31

    Default Re: Toyota Prado 120 battery draining

    Or could just be battery needing to be changed. Had similar on my previous 120.

    But yeah, first remove unused tracker, then check one in use, lastly the battery replacement.
    2017 Toyota Fortuner 2.8 GD-6 4x4 A/T

  5. #5
    Join Date
    Jun 2016
    Thanked: 2063

    Default Re: Toyota Prado 120 battery draining

    Before you go and change the battery put a multimeter between the +terminal and the cable and check if and how big is the draw. Pull out the fuses one by one and see which one causes the draw. See what the fuse is for and repair. I had the same on my Landy and found a $&@-$ tracking unit in the rooflining after I rewired everything that was working on the fuse that drained the battery.

    2000 Land Rover Discovery II TD5
    2020 Nissan NP300 2.5TDi S/C

  6. #6
    Join Date
    Sep 2006
    Thanked: 448

    Default Re: Toyota Prado 120 battery draining

    Some years back I had the same problem, battery flat after four days. This vehicle had the old Netstar unit fitted which had a 6v 4A battery and once this battery gets old, the NS tries to charge it, drawing some 800mA in the process. 800mA equates to 19 Amps in a 24-hour period, and thus some 76A over 4 days.

    The solution was to replace the old Netstar unit with a newer model which does not seem to have this problem. Or maybe it does, I don't know, I now use a smart charger to keep the battery fully charged at all times and this has solved the problem for me.

    If you have a suitable DMM, set it to the DC Amps mode and check the various positive wires connected to the battery, ammeter in series with the wire of course. That should soon point you in the right direction.

    Eric Skeen is the Family Dog
    White Fang:
    1999 2700i DC Raider 4x4
    Bull Dog: 1987 4Y-EFI 2200 DC 4x4
    Pra Dog: 1998 Prado VX 3.4 V6
    Hound Dog: 2000 2700i SC 4x4

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