Yesterday afternoon the remote locking decided to stop working. New batteries in both keys a couple of months back, and had been working in the morning so not the dreaded 28-day sleep function.
I had seen some odd intermittent failures that seemed to resolve themselves pretty much straight away, but this was persistent.
First thought was "I've got a full tailgate guard and have just fitted a commercial bulkhead.... have I inadvertently created conditions for RF block/interference? To check this I dropped the light in the headlining above the rear seat space and located the RF receiver. After some gentle persuasion with a screwdriver I prised it free of the velcro and dropped it through the opening for the light and held the key directly against it. No bueno.
Next up was to check fuse F21 (5a, brown, under the glovebox) as this supplies alarm and the RF circuit. Fuse was fine.
Reading the codes with my Foxwell, I got U201-87/P.
Click image to enlarge
U201F: External Receiver
87: Bus signal/message failure - missing a message
P: Permanent
Tried clearing the code (I know, permanent, but worth a go) and code popped straight back up again.
Time for some manual inspection of the unit.
First, I pulled Fuse F21 again. No point making this worse by risking a short or similar. Once I had done this I pulled the connector to the receiver, then dismantled the plug to take a closer look. I also popped the receiver out of its casing to see if there was any obvious damage, corrosion or debris that could cause a problem.
Click image to enlarge
Click image to enlarge
Centre pin and corresponding connector showed signs of corrosion
Click image to enlarge
Cleaned each connector with a healthy spray of Halfords contact cleaner (other brands are available, but hey, Trade Card......) and then carefully worked each connector, still soaked in cleaner, on and off each pin several times to clean off the corrosion.
Put the receiver back in the case, reassembled the plug (note pic for order and orientation of cables) and replaced fuse F21.
Ran diagnostic without clearing codes, still showing (as expected).
Cleared codes, re-read them and fault now cleared.
Quick check with both keys and all functions (lock, unlock driver, unlock all, remote window opening) operated as expected.
Used RF receivers are around £15-£20 on ebay so may grab one, give it a test and clean and keep it in my box of spares just in case. 6G9T-15K602-AB but may appear in searches with different spacing/punctuation. See tags below for some possible alternatives.
Going to add some tags so this is easier to find with the search function:
Receiver part no (Siemens VDO) 6G9T-15K602-AB 6G9T15K602AB 6G9T-15K602AB 6G9T 15K602 AB 6G9T 15K602AB
lr044370
Found on various JLR and Ford products from circa 2005 - 2015 inc. C-Max, S-Max, Kuga, Mondeo, Freelander, XF and probably others.
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9th Jul 2022 11:56 am
