Hi, I noticed my 2018 X351 only has one reverse light, the right side, the rest of the lamps on the left side seem fine, I read the codes and it had b13db-11 Left Reverse Lamp - Circuit short to ground, which I found a bit more on here...


...I also have the U1000-00 code they mention.

So a stupid questions before I start going down a rabbit hole...

1. Can someone confirm X351s do actually have two reverse lights in the UK as some cars only have one?
2. If they do, I think the clusters are all LED so I cannot replace a bulb, can anyone confirm?
3. If they are all LED, are they repairable or will I need a replacement tail light cluster?

Thanks in advance.

 

First things first! Before spending any money.
Take both tail lights out and then plug them into the opposite sides of the car. If they work it's not a light problem. If they stay bad then I would replace that tail light. So does the failure stay with the tail light or does it stay on the same side of the car?

Don't understand what Jaguar wrote at all but again it's pointing you to using SDD to scan the car and clear the errors from the BCM (If there are any). You got the deeper 2 digit codes so maybe you do have access to a SDD setup?

I am in the US but have never seen an X351 without backup lights on both sides.
I must add this too so sorry! How old is the battery and what is the resting voltage after the car has sat all night. Again just checking for the obvious stuff first.
.
.
.

 

Thanks for your input, we are on the same page I asked the question before I start any diagnostics as I did not want to waste time trying to fix something if there should only be one reverse light! I assume there should be two but the car dashboard does not give an error message and I would think it would give a bulb failure message, I had to use OBD diagnostics to see there was an error which seemed odd.

In the UK, if there is only one reversing light it is not an MOT failure but if two reverse lights are fitted both must work else it is a major fault and the vehicle will fail its MOT, hence why I need to know if there should be one or two.

You cannot clear the fault, it is back every time you restart the car using the scanner.

 

Yes if it was a bulb I would have thought a dash board light too. So maybe the bulbs are fine and it's deeper in the car?
The error description seems to say wiring damage but the last statement says replace the tail light.

Swap the units side to side and report back I am betting it's a bad tail light.
.
.
.

 

Apologies for the long time in updating this post, been meaning to update it but it is still not fully fixed, I lost the pictures I took, lost the draft reply I made (thank you XenForo), forgotten half of what I did, however this is what I can remember and hopefully will be useful for someone:

Fault 1 - Bad Left Tail Light

1. Moved the left tail light and moved it into the right, reverse did not work. I also noticed that some of the side lights were not working (the J shape).
2. The caps that are on the back of the lamp unit were not there, so I think someone has been there before trying to temporarily fix a ‘condensation’ problem, I could see quite a lot of condensation in it and when I turned it upside down some water came out (more on this later).
3. Bought a good secondhand unit plugged it into the left position, still no reverse light but the rest of the side lights were now good. I swapped it to the right position and everything was spot on, plugged the right tail light into the left wires, no reverse light. So I now had two good tail lights but still only one working reverse light.
4. FYI and when looking for parts, a new tail light from Jaguar is £760’ish inc VAT so it's worth trying a used one first. I found out that part C2D60948 is the latest left tail lamp and part C2D60948 is an older one. From speaking to Jaguar parts, they are all compatible but as they find faults (such as places where they leak!) they bring out a new part number. The engineering code is FW-9313405-AC and is on the paper sticker (see the pic below), the last two characters are the revision, mine was a “AB” and the used one I got was also an “AB” but if you can find an “AC” all the better.

Fault 2 - Wiring Issue?

1. From a bit of research it seemed like the BCM might need to be reset to re-enable the output as per TOPIx - SSM74171. I took it to a Jaguar specialist who tried this but it made no difference. The specialist's opinion was that the BCM would try each time the car started before disabling the output. Could it be a faulty BCM as well? Thinking about this further and checking the wiring diagrams, the BCM only sends out one power feed for both tail lights and then splits off to the right lamp somewhere in the wiring loom. As the right side was working the BCM must be fine and it is a wiring fault.
2. As the vehicle passed its MOT this is where I got to.

Next Things to try to find the wiring Issue

1. When I took the left wiring plug out the tail light there was some green on some of the connectors but I did not think it was the reverse pin, I cleaned it up but there might be an issue further down the pins or the wires corroded in the plug because of the water. The next step will be to de-pin and see if I can see anything wrong, else it will be a fault further down the loom, probably at or just after where the power wire for the left lamp splits off to the right one.
2. If it is only one wire powering both reverse lights, how does the car know the left one is not working and the codes generated? From reading the repair manual and looking at the wiring diagram, the vehicle works out if there is a fault by using the earth and each tail light has a different earth point so this makes sense, as there is only one earth for each tail light and all other lamps work, it still points to being a wiring fault..

Bad Tail Light Root Cause Analysis and Dissemble

1. Just for fun I wanted to work out why water had gotten into the lamp unit as I could not see any obvious issue
2. To test, I sealed the two holes on the back and dipped the lamp unit upside down into a large bucket of water so that the top 50% was submerged and left it for 10 mins. I removed the covers and no water came out so that seemed fine.
3. Repeated but this time submerging the lower half, this time water poured out. On close inspection I could see where the red plastic and the clear that is in the center of the units were not flush on one side, you could catch it with your finger nail. I could not see any damage so I think it is just a ‘feature’ of the design. I also left the lens in the shed over summer and winter and when I check it again it is now flush so maybe it is a heat thing where the plastics expand at different rates and can split but when they are not in the sun they are ok. Note to all X351 drivers, reverse your vehicle against a wall to keep the tail lights in the shade
4. In case it is useful for anyone else, I also bench tested each tail light using a 9V battery, by putting negative on the earth pin and then the positive on each of the other pins the LEDs light up fine with that voltage, for the orange indicators they are sold orange of course as the flash comes from the car. Handy to know if it is cold and wet and you want to do testing in the house 🙂
5. I took the lamp unit apart (used a dremel to cut out the lens from the black plastic case) to see what damage was done and to see if I could fix it (just for fun). After some cleaning and resoldering, all of the LEDs worked apart from one and I managed to get most of the circuits working but not all and I think this is because some of the metal contacts on the circuit board have gone, lots of the solder joints are just dust etc, some pictures below (there is lots of green in the lower part of the lamp from sitting in the water) in case you are interested…

 

I've had no reverse lights since I purchased my car, and I have narrowed it down to a BCM fault also. The cost of a virgin BCM and the hassle of registering it in SDD has prevented me from fixing the problem. I verified this by putting the car in reverse and checking for voltage at the reverse light pins on the harness; there was no voltage.

 

Looks like they do not share anything from left to right. If your output is disabled (that U1000 code), you may need to run the 'enable protected outputs' function in the BCM to get the light back on.
You can try doing a battery reset, it might bring it back if the circuit is fixed. The module detects the short and over-amperage and turned the output off, it needs to know that it's fixed before it tries it again. There are no fuses in the circuit, so this is how it protects itself.

 

Out of interest, how have you worked out for sure that it is a BCM fault? What I have not done yet but thought I should was test the continuity from the pin on the lamp plug and then the corresponding pin that goes into the BCM. Which pin that is in the BCM I am not sure and because it is behind the rear seats it is not easy to check without some dismantling. However, if this is good (and I could compare it to say the stop light wire) then it would look like a BCM fault but if not it seems like it is a wiring fault which is my current thinking.

I am also not 100% sure if the BCM will never try the circuit again once it has gone into its self-protection mode and associated U1000-00 (Solid State Driver Protection Active - Driver Disabled) code or if as my specalist thought that it would try it again when you start the car, the TOPIx pdf I put a link to suggests it is permanently disabled until you tell it to try it again via SDD.

 

Do you know this 100%, as per my previous post, TOPIx suggests it works like you suggest and you need SDD to get the BCM to try the circuit again but if this is the case, I still have a fault somewhere as this has already been tried.

Also out of interest, where did you get the circuit diagrams from, I think mine a back and white

 

That's from Topix, the factory workshop manual.

Yes, protected outputs turn themselves off and need to be re-enabled. Some later modules and different applications will attempt to re-test them after so many cycles, but a lot of the older ones it's simply off until that procedure is run via SDD to turn them back on.

You can try a battery disconnect, which may clear the code and restore functions.

 

I confirmed it by tracing continuity between the BCM pinout and the lamp pin at the back of the car. And there is no voltage at that pin in Reverse.