Did you end up going with the actuator from europarts? Looking to replace mine and not sure what direction to go.

 

I got the one on Amazon branded scsn. Currently $120. Been working great for a few months now. Several off road trips to test it out as well.

 

thanks I ended up getting the $400 one off of Amazon. Should be here for the weekend. Did you calibrate yours after install?

 

Thank you, DakotaTravler, for this thread. Gave me the info/confidence to tackle this issue on my '15 LR4 with HD. I'd like to add my experiences with this here as this is the most useful source of info I found and may hopefully continue to help others.

My issue started with a "Rear Axle Fault" notification on the dash which caused the truck to go into reduced performance mode - no HDC, special programs disabled, suspension lowered "for safety", brake assist disabled. This, of course, happened immediately after spending a substantial amount of time replacing the rear coolant crossover (heater manifold) pipe - drove for about a week with the glowing feeling of a finally sorted Land Rover and boom. Axle Fault.

Anyway, I pulled the fault code(s) with the GAP IID tool and got a "P186D-97 (FF) - Clutch Actuator Stuck - Component failure - component or system operation obstructed or blocked" in the RDCM. This was the only code present and returned immediately after clearing. Cycling the ignition button, I could hear the actuator energizing. No squeaks, just a humming vibration. I placed my hands on it while my wife cycled the ignition to verify it was the diff actuator. I ran the rear differential test using the GAP Tool - it "passed" the test, but the fault code persisted and the truck stayed in reduced performance mode, so I resolved to replace the actuator.

I too decided to gamble on an aftermarket (Chinese) actuator that I found on Amazon. The genuine was just too expensive, and only included the motor itself without the gear housing, and the bolts on mine were so badly corroded that the torx head stripped immediately when attempting to de-couple the motor from gear housing. Rather than spend the time drilling them all out I figured it was worth the gamble to try the Amazon actuator that included everything. Comparing the two (original actuator removed from my truck and new Chinese actuator) there were no apparent differences. Even the play/tolerance in the gear felt very similar. I should also note that the actuator I removed was definitely stuck - I broke it free by forcing the gear, but could feel it grinding inside the motor housing. So I assumed that was the issue, and confidently proceeded to replace it with the new one.

Definitely a bitch to do, but your writeup helped greatly. The worst part was cleaning the mating surface - I used a mirror with an LED light from Autozone - and trying to get a clean bead of sealant on there. My hands and forearms still ache from the contortions required. I used the Permatex grey "Right stuff" RTV - which sets up quickly and doesn't require 24 hr cure before use, but it gets sticky and messy fast if you're not careful. I also found that the only way to get the actuator with gear assembly attached in and out was through the passenger side of the diff, up and around the fuel fill pipe. I can't give any clear instructions as to how I did this - there were some rotations involved and a lot of swearing, but eventually got it out (and the new one in) going this route. I covered the gear and mating surface of the new one with some painters tape to try and protect it a bit when routing it up and over the diff, then removed the tape once it was correctly oriented, and seated it down on the fresh sealant bead.

After torquing the bolts and twisting on the wire plug connector with no issues I was feeling pretty good. When I turned on the ignition I again heard the motor energizing - this time with a slightly different tone but roughly the same duration as before. I cleared codes and ran the self-test again, which passed with an "operation successful" (or "complete" maybe) notification on the GAP. The original P186D actuator stuck code is gone, but I have a new code that is resulting in the same reduced performance mode (no HDC, no special programs, no suspension control). The new code is "P0810-62 (FF) Clutch position control error - Algorithm based failure - signal compare failure". It is the only code present and returns immediately after clearing. I tried cycling the ignition numerous times, and drove the truck back and forth slowly down the driveway and around the cul-de-sac to do some tight circles in hopes it would learn and/or calibrate itself, but the code persists.

At this point, I'm thinking either A) I need a firmware flash to get the RDCM and new actuator communicating correctly? or B) The aftermarket actuator is bad or the motor is insufficient/out of spec in terms of providing the requisite torque to properly position the clutches, triggering the position control error?

Any suggestions or insights would be greatly appreciated. Again, thanks for this thread!




I used a standard sized 3/8 ratchet with a small 2 1/2" extension and 8mm socket for all bolts. Right arm up between driver's side exhaust and frame. Left arm up between passengers side exhaust and prop shaft. I was even able to get my small inch/lb torque wrench up there to torque to 7 ft/lb

 

When I installed my locking differential on my LR3 it threw a clutch position sensor (IIRC) error immediately and only on the second self-test did it clear and stay off. If you have only done the self-test once, I would do it again. I have put probably 2,000 miles on the truck since I installed the locking diff and one time in ~ 7 months it has thrown the error code again. The self-test immediately fixed it that second time and I have not seen it again.

If repeating the test does not work, reach out to GAP to see if you're running the most current firmware.

Good luck with it,
- scooter

Edit: one other thought, take a look at the harness connector on the old actuator, are the connection points clean or does it look like there's corrosion?

 

Do a hard reset - disconnect the battery for a while. I know some say 10 minutes, but the longer the better. Do that first and see what happens. But I dont recall have the reduced performance issues like you are having. Do you mean reduced traction? That fault I did have. On a side note, the second cheap replacement sent to me has been trouble free excluding a couple little glitches after install. And I have dont things that certainly exercise it.

 

Thanks, scooter - I did run the self-test multiple times but the clutch position fault remains. I tried again yesterday evening after letting it sit for a while. The rest of the warning lights are gone and there is no longer the "Axle Fault" message on the dash, or any of the restricted performance issues. Suspension working normally and I can select all Off-Road modes again. Everything seems to be working as it should, except for that code continually showing up via the GAP tool. I'm pretty certain now that the only issue before was the stuck actuator, and now the new actuator seems to be functioning fine, so I think I'm going to just drive normally and monitor closely for any weirdness. GAP tool does say there is a Firmware update available for the RDCM so I may do the Fast Lane service for that flash as well. I will also check the harness connector - the contacts were very clean on both the actuator and plug when I removed the old one, but I should have verified before plugging it in after wrestling the new one over the diff. There is a lot of dust/grime/debris that could've gotten in there. I was so relieved to have gotten it in position, and a bit hurried to get it torqued before the quick-curing sealant set up, that I didn't take the time to inspect the contacts. Maybe some grime got in there. Thanks again!

 

Thanks Dakota - I will try the hard reset. Hadn't done that yet, but leaving it sit for a while seems to have resolved the reduced performance issues. Yes, the traction control was disabled as well, along with the HDC (hill descent), all special programs were disabled, suspension control was disabled too - basically a 3 amigos/christmas tree dash situation because of the "Stuck Actuator" fault. The new "Clutch position signal plausibility" fault is still there, but doesn't seem to be causing the cascading dash warnings - no lights on the dash and everything seems to be operating as it should. Maybe the voltage of the comms signal from the aftermarket actuator is slightly out of spec or something and is triggering the "signal plausibility" code? Last step is to update firmware from GAP and see what that does I guess, but for now, I'm considering it a win for the $175 actuator.

 

For documentation purposes - this is the new code. It does not clear after self-testing multiple times, but does not seem to be affecting the

performance of differential or any other systems.

 

The update is required for the rear diff or you will have issues.

I would def make sure the connector is 100% locked into place.