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Thread: First time off road in my P38.. and ABS/TC failures?

  1. #1
    Join Date
    Sep 2016
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    Upper Caboolture
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    First time off road in my P38.. and ABS/TC failures?

    Hi everyone, I've just returned from a 3-day camping trip at Janowen 4WD Park at Goomburra in Qld - I've been there quite a few times in the Discovery 1, so it was interesting to contrast doing the tracks in the P38.

    Lookout.jpg

    MtGoomburraEdit.jpg

    The first change was going from a diesel manual to an auto - and the fuel use.. But it was certainly very comfy doing the runs.

    When I took the Rangie through a flex test in the playground, it did flash up the traction control for a sec.

    However I did find that after climbing some steep and somewhat slippery gravelly rock hills (in dry conditions), both the TC and ABS would often report "failures". Is this a product of the computer dealing with wheelspin on one side/one wheel? Why would this produce a failure, instead of just letting me know it had activated? As I understand the P38 doesn't have the 'diff lock' my Disco has.. On restarting, everything was fine.

    And the other thing of note: on one quite steep climb I lost traction, with the Rangie rolling backwards briefly while still in 'drive' until I had time to react. The engine turned itself off, and on restarting it would not go into low range (even with the selector pushed across and beeping in neutral), plus there was no gear display on the LED dash readout. I guess this was it going into 'safe mode'? When I turned off the vehicle soon after to check out the track, it beeped and said "transmission fault". However when I started up again, it ran as normal - going into low range and running normally for the rest of the trip.

    Maybe all this is just the fun of owning a car with so many electronic checks on its operation?

    Anyway, had a great getaway in the P38!
    P38A 1996 Range Rover "barn find"
    1986 Suzuki Mighty Boy - sold
    classicandclunker.com

  2. #2
    Join Date
    Jan 2016
    Location
    Netherlands
    Posts
    117
    Hi there

    The TC and ABS should not come on unless something -is- wrong. Sure, when the computer intervenes and starts braking wheels due to wheel spin, it will let you know it does so by turning on the lights on your dash. However, as soon as the control has been regained, the computer will cut out again and the lights should turn of.

    I take it your matrix display (in the centre) also gives you an error message? Sometimes improperly seated ABS sensors will cause an error message to pop-up when driving slowly and ever so slightly breaking. I get it often when I reverse but am too lazy to reseat the bloody buggers right now

    So, it could be an ABS sensor that is out of whack. If you have the possibility to read the error codes from your P38 it'll tell you why it cut out. Also, it is normal for the error to be cleared from the dash when restarting the vehicle. The errors are retained in memory though. What could also be a problem is that the P38 does not use vacuum assisted brakes, it uses an electricly powered pump to keep up brake pressure. This pump can fail or the black sphere on top can fail and you loose brake pressure. You can recognize this when you brake 4 times the pump should kick in. If however the system has issues it'll kick in more often and when starting vehicle in the morning it will run for a long time to build pressure back up (I have this problem right now). When the ABS/TC kicks in the brakes are applied and released often so there is a lot of loss of pressure that needs to be replenished by the pump. When it can not keep up (which it should under normal circumstances) the BECM will also throw an error.

    Regarding "stalling" and the low range selector. That is odd. First of all, the car should never stall. Either the torque converter will keep the car stationary, or, when not enough power is applied or the angle too steep it will slip and the car will move backwards but I have never had it stall or cut out under any condition and I have been going up and down some crazy steep hills. I am not sure what happened but if I understand you correctly the vehicle was in high and you wanted to switch to low range? The transfercase houses the low and high range gears and they are selected by means of an electric motor that is operated by a switch in case of a manual or in case of an auto by a switch in the H pattern gear selector. If low range is not selected regularly the motor can seize and then things go real bad real fast. Perhaps your P38 was not used of bitumen often and the transfercase is a bit stuck (guess you loosened it up though!)

    And finally, yes, the P38 does not have a centre locking diff but a viscous coupling which is basicly a limited slip centre diff. And I mean limited!

    In all, I hope you find the problem, but it sounds to me that the car needs some TLC.

    Cheers,

    -P

  3. #3
    Join Date
    Sep 2016
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    Thanks Prelude, yeah I reckon it might be the first time it's ever done some serious offroading..!

    Thanks for your advice - I will see about getting error codes read - I have an old OBDII scanner which plugs into a computer, not sure if that will be useful?

    It was in low range when it stalled - yes, I agree it was very unusual for this to happen.. I'll keep an eye on this too.
    P38A 1996 Range Rover "barn find"
    1986 Suzuki Mighty Boy - sold
    classicandclunker.com

  4. #4
    Join Date
    Feb 2010
    Location
    Townsville, QLD
    Posts
    2,456
    With regards to your ABS/Traction failure, if the traction control works hard for a long period of time it can overheat the ABS pump. This may have been the case for you.

    Stalling, on the other hand, could be related to a few things. Perhaps the fuel pump sucked dry due to an angle, and the engine starved for fuel briefly? It should never happen normally as the torque converter should absorb it.

    Cheers
    Keithy

    Green 2000 P38 Range Rover HSE - Gone
    Blue 1999 P38 Range Rover HSE - Gone

    Silver 2002 P38 Range Rover HSE - Sequential LPG, BCDC Charger, TPMS, Rear Locker, Wheel Carrier, Bullbar & Spotlights, General Grabber AT2's, Too Much to Mention!

  5. #5
    Join Date
    Jan 2016
    Location
    Netherlands
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    Right! over heating is indeed possible as well, though I never had that happen thus fat. The error codes should register that.

    The P38 has a OBDII compatible port but nearly everything that is computer controlled (which is just about everything on this car) can be accessed through that port and most of it is not OBDII compatible. I'm affraid you'll need someone with a unit specific to this car. They should be around and only having all error codes read (and cleared) should not cost too much imho.

    If you plan on keeping the car for a longer period of time and intend to invest in it you may want to but a nanocom or faulmate for example to be able to do all this yourself. I have found it invaluable though I'm having trouble using it lately.

    And finally, it has been said a dozen times but I'll repeat it here our cars REALLY do love their 13.8volts. Anything lower and the computers stop playing nice. A bad battery, alternator or corroded ground points will all add to unexpected electronic behaviour impacting all that is electronically controlled, which is, again, everything.

    Keep us posted mate!

    -P

  6. #6
    Join Date
    Aug 2010
    Location
    Pakenham
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    578
    I had this problem too over the weekend when off roading. Today when changing the wheels back to my all terrains, i pulled out the sensors and gave them a clean with WD40 as well as the seating, and the internal sensor wheel to drive out any moisture and dirt that may have gotten in.

    now when re-seating, make sure you push the sensors all the way in until it touches the internal sensor wheel. Don't worry it won't break the sensors, because as soon as you start driving, it self adjust to the optimum position. Take it for a test drive to make sure the ABS & TC lights go out when you drive off. If it's still on, then I'm affraid your going to have to re-seat them again, as one of the sensors may not be all the way in. You don't necessarily have to take the wheels off, as you can access the sensors from behind the wheels, it just makes it a bit easier to access if you do take the wheels off, your choice!!

    if the failures persists, then you may be up for new sensors, and a phone call to Dave at British Car Components for replacements.

    Hope this helps!!

  7. #7
    Join Date
    Apr 2010
    Location
    Lower Hunter Valley NSW
    Posts
    311
    Took my P38 off road at Wallaroo SF 2 weeks ago and was really surprised how well it managed slippery up hill rock and mud. That traction control worked a treat!
    Current: MY99 Range Rover HSE with 5.0L V8
    Past: MY01 Discovery V8 - drowned , MY03 Discovery HSE V8 - sold

  8. #8
    Join Date
    Aug 2010
    Location
    Pakenham
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    Quote Originally Posted by banarcus View Post
    Took my P38 off road at Wallaroo SF 2 weeks ago and was really surprised how well it managed slippery up hill rock and mud. That traction control worked a treat!
    oh they're good!!

    They are a proper traction control where it works the brakes, not a cheapy that just reduce power.

    it takes a different driver approach as to not take your foot off the accelerator the second you may think you're bogged. It usually works itself out within a second or two and keeps on going.

  9. #9
    Join Date
    Jan 2016
    Location
    Netherlands
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    The TC does work really well but I'm afraid it does take it's toll on your system. I bought my P38 initially just to throw it around on those mudding days we have down here. No such terrain as in .au so we often have a closed dirtbike track that is modified with a bulldozer or a private persons land that allows you to drive through the woods. All in all, it's mainly: how to get your vehicle stuck and more importantly, how to get it out

    When I first got the car, all was well. After a few of those days of hard plowing (on winter tyres since I did not have decent muddies back then) the car still looked ok but I noticed the pressure in my brake system did not keep up. I replaced the accumulator (the black ball on top of the pump) and all was well for the months after that, but then again, I only went greenlaning in wales. We're now some months on again and the brake pressure is really struggeling. It could be that I have a defective accumulator, I am rebuilding my ABS modulator with one of Russel's kit's so maybe that solves the pressure problem as well, else I can only say that the traction control/abs really does wear out the brake pump A LOT.

    So, I would really consider a locker, it's easier on the drive train and it's better for the pump / modulator in the end

    Cheers,

    -P


    PS if you do have a GEMS / older modulator, it is really recommended to do the BMR kit for the modulator since a valve can fail and that will result in NO braking power whatsoever...

    PPS I am in no way affiliated or whatever with that bloke

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