I recently had my V8 engine replaced with a rebuilt one due to a head gasket issue. When I got the car back, the mechanic asked, "your doors didn't lock with the remote, right?" Both key fobs were working prior to the engine swap. Now neither key fob unlocks or locks the doors, but the central locking button on the center console still works fine. The vehicle starts without any issues, so I believe this is not an immobilizer issue.

I've confirmed that the battery on the fobs are measuring 3V, but I do not have a way of checking that they are transmitting. I went to three different auto stores and they all have gotten rid of their remote tester. Regardless, it seems unlikely that both remotes would suddenly stop transmitting.

Years ago I made the splice repair on the green/white (G/W) wire that runs under the passenger door sill, so I did not bother examining that. The floorboards are dry and there has been pretty much no rain in our area during the time of the repair. I checked voltage at the wire connecting to the RF receiver in the headliner; with the ignition off, the G/W wire measures 12.5V. There is also 11.5V on the blue wire, which I think is not right. Pulling fuse 43 at the central junction box eliminates the voltage on the G/W wire, as expected, but the blue wire continues to show 11.5V. The blue wire goes to C586 on the back side of the CJB and I've confirmed there is continuity on the wire. Voltage remains on the blue wire even if all the fuses in the CJB are pulled. However, pulling connector C583 causes the voltage to go away; I believe this connector provides power to the CJB.

My guess is that there is some fried circuitry in the CJB. I am leaning towards cracking it open to check. I've already tried pulling and reseating just about every fuse and relay, disconnected the battery multiple times, and also pulled out and reinstalled the entire CJB. I also purchased a used RF receiver and connected that with no success. Can anybody provide some guidance as to what I might be overlooking? I've checked over on the disco3 forum and in the cases where somebody had an identical issue, it was resolved by "I disconnected the battery and upon reconnecting, everything worked."

You might be wondering why I don't have the mechanic who replaced the engine address this issue. I don't feel that he has the ability to diagnose something like this.

 

"Years ago I made the splice repair on the green/white (G/W) wire that runs under the passenger door sill, so I did not bother examining that."

Odd, that would be the first thing I would check. How did you repair it, solder and shrink tube?

 

Yes, it was a proper solder and heat shrink repair. You are correct, in order to get a full diagnosis I should revisit the splice. I'll take a look at it later this week.

 

I finally had the time and mental energy to look into this further. I pulled up the passenger side sill to check the splice and it looked good.


Nicely ziptied from the previous repair that was done over 10 years ago. Thank you past self.



Splice seemed good. I had soldered the wires together and used heat shrink along with electrical tape at the ends.

I used a multimeter and confirmed again that the feed from both wires going to the central junction box is good. I even took apart the CJB to see if there was something damaged inside.




I think I’m going to have to either take this to the dealer or just live with locking the doors manually.

 

If you have a GAP tool (or similar), I would consider a $20 eBay fob, and try the tool's programming function (all keys)
You might end up with 3 working fobs - or possibly just 1 working eBay fob

Either way, seems like a win - unless someone knows something potentially negative about this suggestion

 

I did some online searching and came across a post on a Range Rover forum saying the alarm and remote locking might be deactivated. I pulled out my Faultmate and starting looking at various settings. In the process I somehow wiped out my car’s config file!

I was able to rebuild the config file but the car was not happy and Faultmate was not recognizing the car. After some more poking around I noticed there was no entry in the VIN parameter. I entered this info and everything was happy, including the remote locking.

I can’t say what was the definitive issue. I’m just happy I can lock and unlock the doors remotely.