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Thread: 8 speed shift lock solenoid problems

  1. #1
    Join Date
    Jan 2013
    Location
    Brisbane
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    91

    8 speed shift lock solenoid problems

    P176C-11 Transmission range selector lock control error Ė General electrical Failure Ė circuit short to ground

    Background
    The shift lock solenoid is a safety lock to prevent the transmission from selecting a drive mode without having the brake pedal applied. It will only lock in Park & Neutral and should never lock in Drive or Reverse.
    In the event of a no power condition (ie; flat battery) the 6 speed transmission in the discovery 3 and 4 (as most cars do) have a ďshift lock releaseĒ to release the shift lock solenoid which enables the gear lever to be moved to the Neutral position, as this lever is connected to the transmission via a physical mechanical cable, it will select Neutral without power.
    Unfortunately in the 8 speed transmission there is no physical cable connecting the shift dial to the transmission, the only connection is ďelectronic dataĒ via the vehicleís CAN BUS network (with a local network connection to the transmission as a backup). In the event of a no power condition, turning the dial (if you could) wouldnít do anything.

    The Problem

    What Land Rover did to overcome this issue was to add a mechanical cable that enables you to shift to Neutral without turning the dial, now this works well if you want to get towed, but what if you DO have power, a good battery, parked on the beach, engine running, tide coming in and the dial is locked in Park (or locked in drive with the engine off) due to a faulty shift lock solenoid. There is the real problem, you canít select drive as there is no shift lock release (and you canít start the car if the dial is in Drive even if you pull the Neutral lever).

    Quick get me off the beach solution

    (tools to keep in the car; T20 Torx driver, Philips Drive)
    What we need to do is access the (TCS) transmission Control Switch, the rotary dial bit.
    First we need to remove the cup holder and the spill tray below it using the Philips driver (or a small flat blade if thatís all you have).
    Open up the centre console lid and start pulling up on the sides of the centre console where the cup holder is, the entire centre section surrounding the TCS should lift up and come free. It will slide backwards away from the dash.

    1.jpg


    Now the Centre is loose, roll the entire assembly onto the passenger seat, taking care not to stretch the cable harness, I donít recommend disconnecting the main harness as you will get a large number of faults and the dash cluster goes off (you have enough fault codes to deal with already).
    Using the T20 Torx Driver undo the 4 screws holding on the plastic trim surrounding the TCS, also unto the 4 screws holding on the Mode selection/height/low range switch panel.
    Two of the screws are hidden behind the Gray and Green connectors, if you cannot access these screws simply release the connector from its holder BUT donít disconnect the connection itself.
    Important Note;
    The brass screw at the base of the TSC will raise and lower the rotary dial, it will be very easy to turn, the dial can be used (turned) in the fully lowered AND fully raised position, however do not turn this screw if the dial is not in Park, the dial will attempt to rotate to Park as it is lowered, if your shift lock solenoid is in the locked position (unpowered) and the dial is in anything but Park you will break something.
    2.jpg

    After undoing the 8 screws roll the entire assembly back into its normal position. (Making sure that all electrical connections are still in place)
    Carefully remove the plastic surround from the TCS, you can gently lift it up from the cup holder side, part of it will sit under the Mode selection/height/low range switch panel.

    3.jpg

    Using the T20 Torx driver, remove the 4 screws holding the TCS into the console, you can now lift the TCS out of the console and lay it on its side.
    Remove 3 of the 4 screws on the outside edge on the base of the TCS, do not undo the screws in the centre of the unit, they hold the motor and solenoid in place.
    4.jpg
    You must do the following with the dial in the raised position, if youíre in Drive the dial will be raised, if youíre in Park raise the dial by turning the brass screw, and be gentle.
    The last screw we will use to hold everything together, undo this screw so that the unit is held together but open enough so that you can place a screwdriver into the unit and release the shift lock.
    Important Note;
    The shift lock is plastic, be gentle. The circuit board doesnít want a short circuit, be careful. I used a screwdriver but you could use something non conductive.
    We donít want to open the unit too far because the gear selection circuitry uses magnets and magnometer sensors, opening the unit separates the two, open too far and the chip wonít see the change in gear when we turn the dial, or may see an invalid selection.
    5.jpg
    Fully opened view of the TCS (taken during the repair procedure, you donít need to open the unit this far yet)
    6.jpg

    What we need to do is gently release the shift lock with a screwdriver (or non conductive tool) with one hand and turn the dial with the other hand (if turning to drive or reverse you will still need your foot on the brake pedal (and a working brake light switch))
    Once you have made your gear selection, we need to tighten the single screw holding the unit together and if driving some distance I would place the TCS back into its correct location.
    An alternative would be to use an elastic band (hair tie, string, zip tie etc) and hold the shift lock open. If you do this you will get a second fault code stating a mechanical failure of the shift lock, and you can only select a drive mode whilst the brake pedal is pressed (working brake switch), turning the dial to drive without the brake pedal results in a flashing D or R on the dash and no drive.

    The work around fix
    This fix is good for fault finding an intermittent fault and for peace of mind, it involves creating a shift lock lever under the cup holder that will quickly release the shift lock if the solenoid fails, however I donít recommend using this method for long term use (who wants to lift the cup holder for every gear change?). And remember if you have no power using this will not enable you to select Neutral, you will still need to use the red lever for that.
    Perform the procedure above to remove the TCS, once the TCS is free, disconnect the TCS cable, you will need to raise the red locking lever/tab to remove the connector, again nothing needs to be forced so donít break anything.
    Take the TCS to a clean workbench or kitchen table, the TCS does contain static sensitive circuits so take care not to have any static build up (google that if you need to).
    To open the unit fully we will need to remove the black plastic centre cap from the metal dial, the cap is held on with double sided tape, to do this we push a small flat blade screw driver between the edge of the plastic and the metal dial and lever slowly up, I also used a box cutter and pushed the blade into the small gap once it started to lift (be careful if you do), I managed to get this off without any issue but donít worry if you damage the cap as aftermarket replacements are available in a range of colours.


    Once the plastic cap is off we can remove the metal dial using a T20 Torx driver.
    Turn the unit over and remove the 6 T20 Torx screws, 2 hold the plastic cover around the connector, the remaining 4 hold the unit together around the outside edge (donít remove the 3 screws in the centre of the metal section, they hold the motor and solenoid in place)
    Remove the plastic cover from around the connector first (taking care not to bend the connector pins), under this cover there are two cables one for the solenoid and one for the drive motor (to raise and lower the dial), disconnect both cables.
    You should now be able to separate the TCS into two halves.
    As the picture above

    Next weíre going to drill a hole into the case and through the end of the plastic locking mechanism, Iím not going to give measurements but you will want the holes to line up and be roughly 3 mm, take your time (measure once and drill twice, or something like that).
    9.jpg

    Take a long thin zip tie and loop it around a key ring and zip it up (this will be your ring pull), then thread the other end through the hole and connect a second zip tie to this, cut off the excess zip tie and the rest of the second zip tie. The zip tie is flexible enough to loop around and apply pressure on the mechanism when pulled from the cup holder side of the TCS. This is what I used but you can use string or anything similar on hand, just ensure that the mechanism is free to move when no pressure is applied.

    10.jpg11.jpg

    Then put everything back together and refit the TCS into the car, feed the zip tie and ring pull around the TCS and into the cup holder area, I used loose zip ties to hold the ring pull in place.
    You may have a few extra fault codes from removing the TCS, simply clear these if you have a Diagnostic tool.

    The Fix and further testing
    My fault disappeared, I was expecting it to return at some point but I continued to drive on, comfortable that my newly installed shift lock release would keep me going if it did. And a few days later the fault returned.
    12.png
    Again remove the TCS and open it up,
    Optional Step if you wish to remove the solenoid, it is possible to test without removing it; we will need to remove the silver foil sticky black sticker thing that is attached to the front of the TCS (Alternatively cut through the middle of the foil where the plastic meets the metal). Then you can separate the lower section of the TCS into two (we now have three parts Top - printed circuit, Centre - Magnets and shift lock, & The Lower Metal with the raise / lower motor & shift lock solenoid.
    Note; Careful not to pull out the main shaft as parts may fly out and we need them all in to work
    13.jpg
    Firstly, I tested the shift lock solenoid itself, Itís rated at 9 volts and I measured the resistance at 6.1 Ohms, using a 9 volt battery is was clear that my solenoid works.

    15.jpg

    14.jpg

    From here I inspected the printed circuit board with a microscope looking for damage or cracked solder joints, I found nothing, everything looked good except for a slight burn mark on a 1 Ohm resistor. I decided to re-solder several components next to the solenoid connector, you will need a good quality, small tip, high temperature soldering iron (mine was set at 420įC+), most solders used on modern circuits have little or no lead which makes them harder to work with.
    16.jpg
    Circuit Board
    17.jpg
    Burned Resistor marked 1R00 and area of interest.

    After re soldering my TCS has worked continuously and I still have my lock release if needed.

    Disclaimer
    This is what I did for my issue and it worked for me, this will not fix other issues and will not fix a broken transmission, you will void any warranty on this unit by performing this repair, as always you undertake this repair at your own risk.
    Attached Images Attached Images
    • File Type: jpg 4.jpg (114.0 KB, 68 views)
    Attached Files Attached Files
    Last edited by Mattblack59bus; 17th November 2019 at 09:21 PM. Reason: Addition of PDF file

  2. #2
    Join Date
    Jan 2007
    Posts
    552
    Great post..should be very usefull for anyone stuck in a precarious situation. As I know such failure can arise at any time usually in a bad location too!

  3. #3
    Join Date
    Jan 2013
    Location
    Brisbane
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    I have added a PDF file with a few annotations on the pictures. My next trick is attempting to fix the green LED ring.

    Cheers
    Marc

  4. #4
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    Mar 2016
    Location
    Perth
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    8 speed shift lock solenoid problems

    Quote Originally Posted by Mattblack59bus View Post
    I have added a PDF file with a few annotations on the pictures. My next trick is attempting to fix the green LED ring.

    Cheers
    Marc
    Iíve got a failed LED in my terrain control switch LR036077. Itís the High range LED. Flags in the IID as a fault too. I was interested if it was possible to repair but havenít pulled it apart. Not sure if it would be the LED, LED driver, or a bad solder joint given your findings.
    Look forward to your findings.
    2010 TDV6 3.0L Discovery 4 HSE
    2007 Audi RS4 (B7)

  5. #5
    Join Date
    Jan 1970
    Location
    Hunter Valley, NSW
    Posts
    98

    Amazing! This is why we love this site!

    Really enjoyed reading this post.
    A huge thanks to Mattblack59bus for taking the time to investigate and share in such a comprehensive manner.
    As a proud owner of a 2015/16 D4 it has not occirred that the sexy little knob may one day not 'rise to the occasion' or not perform as designed.
    Even though I don't intend to risk the incoming tide situation, I am still an hour away from my LR dealer in Newcastle, and so now I have added a 20Torx, a plastic blade and the PDF print out in my toolkit.
    Thanks again!
    Cheers,
    Grahame
    2015 Firenze Red Disco 4
    2017 Firenze Red Disco Sport

  6. #6
    Join Date
    Jan 2007
    Posts
    552
    Wish me luck I'm about to attemp a fix. Dealer wanted 375 for diagnosis alone..so I declined..at this stage anyhow.

    Replacement TCS unit is LR090489..cost $880 from dealer via Melbourne. Dealer said they are seeing a few come thru lately with this problem and LR is not contributing to the fix unless warranty applies..which is now unlikely in most cases.

    No cheaper from OS either unfortunately😐 and used units are also up there in price.

  7. #7
    Join Date
    Jan 1970
    Location
    Hunter Valley, NSW
    Posts
    98

    Replacing the TCS

    Best of luck with your 'fix' - meanwhile, is the car driveable?




    Quote Originally Posted by INter674 View Post
    Wish me luck I'm about to attemp a fix. Dealer wanted 375 for diagnosis alone..so I declined..at this stage anyhow.

    Replacement TCS unit is LR090489..cost $880 from dealer via Melbourne. Dealer said they are seeing a few come thru lately with this problem and LR is not contributing to the fix unless warranty applies..which is now unlikely in most cases.

    No cheaper from OS either unfortunately😐 and used units are also up there in price.
    2015 Firenze Red Disco 4
    2017 Firenze Red Disco Sport

  8. #8
    Join Date
    Oct 2014
    Location
    Brisbane
    Posts
    3,429
    Quote Originally Posted by Mattblack59bus View Post
    I have added a PDF file with a few annotations on the pictures.
    Brilliant write-up Marc, pdf downloaded & printed. Really appreciate the effort.

    I have a query, just so I fully understand how to release the shift lock if ever required.
    Please review the annotated image below & confirm if I have it correct ....

    There's a raised element to the shift lock that can be "pushed", circled in the sketch below.
    This piece sticks up from the main body of the shift lock and protrudes through a slot in the circuit board.
    It doesn't seem to be in all your photos so perhaps it's attached to the solenoid somehow?

    Quote Originally Posted by Mattblack59bus View Post
    An alternative would be to use an elastic band (hair tie, string, zip tie etc) and hold the shift lock open.
    If you do this you will get a second fault code stating a mechanical failure of the shift lock, and you can only select a drive mode whilst the brake pedal is pressed
    If you're away on a trip and need to hold the shift lock open somehow it seems the vehicle will still be operational with this fault code?
    ie you just need to press brake pedal whenever changing between P/D/R but otherwise you are operational until a permanent fix can be made.

    Cheers,
    Scott
    D4 TDV6 MY14 with Llams, 18" Wheels & BFG KO2s, Traxide DBS, Drifta Drawers, Rhino Platform, APT Sliders & compressor plate & Mitch Hitch
    Link to my D4 Build Thread

    Ex '77 RRC 2 door. Long gone but not forgotten.

  9. #9
    Join Date
    Jan 2007
    Posts
    552
    The car is not drivable cause the wife turned it off. Had she not we'd been able to drive forward only. Not sure what would have happened if we'd pulled the rip cord putting the tranny in N...prolly would have meant we could not select drive again...who knows😎

    What a stupid stupid system!

  10. #10
    Join Date
    Jan 1970
    Location
    Avoca Beach
    Posts
    11,982
    The upcomiong and cancelled VXR has/had a pistol grip shifter,and some claimed this rotary dial was NOT fashion.

    Regards PhilipA

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