Hi All,

Order of events:

Drove through a rain storm and got a ride height sensor fault (Driver rear) so I ordered a cheapo on Ebay. Truck had no issues when I pulled it into my driveway which is a bit of an incline, not much though. Found water in the connector, blew it all out, but decided to put the new sensor in anyhow, wheel back on, and all these faults came up and it wouldn't start (not even a crank). Swapped the old sensor back in thinking how could this repair take down all the sub systems!? I had to manually release the parking brake and have the car towed to the back of my home because I couldn't leave it parked the way it was. I was out of town for 2 weeks and it rained almost every day while I was away.

Didn't really do much because I had no idea where to begin! Then I noticed there was a lot of condensation on the inside of windshield. Pulled the carpets back and found quite a bit of water in the passenger side, but especially in the rear wire harness channel. Like I had to pump it out. So I am still unclear if that water came in on the first storm and for what ever reason I was able to start it prior to the repair but not after or if all the water came in during the week I was gone and that something else related to the repair is causing the issue. I am 99% positive that the rain came down my degrading windshield cowel and through the fresh air vent since the filter was soaked.

Today I opened the TCCM and it seemed fine on the inside. I cleaned up the corrosion in the wire harness and on the TCCM (grey connector) but this didn't change anything. Put metal duct tape over the fresh air vent I know of the brake switch, brake bulbs, and low battery voltage issues. I did the brake switch 4-5 years ago and the bulbs seem to work ok today. Correct me if I am wrong but I read that if you simply disconnect the rear lights connections, you can eliminate this? The battery is from 2018 when I bought the truck and it was acting odd and that fixed it. Today it read 11.4v and is now on the charger but I'm doubting it is the cause. Could be a coincidence, but I haven't had any other faults or trouble until the repair. I put my lithium jumper on the battery and still no change. I've pulled and checked all the fuses under the hood. None of the wires in the passenger channel are obvious in any sort of damage. I've read some posts where people find corrosion or broken wires. I have no idea how to go through all those wires! I have tried the hard reset several times

I'm stumped because it absolutely refuses to start and often in these forums, the vehicle runs but maybe some things are turning off and on etc or they get a suspension vault. I've experienced the low battery thing, but if I recall, it would still start. If something occurred during the repair, the things I would maybe consider are an ABS sensor wire got messed with or some other wires down there but what would cause can bus issues to this degree? I know of at least one junction box down there near this wheel that Land Rover has a bulletin on how to seal it up. If it's the water issue (Maybe the water moved around when I moved the truck to my driveway?), then I know I'm in for a ride. I really feel like this was not the cause by the rain and that it just happened to have rained a lot after something went wrong. The first rain wasn't a huge amount but at the same token, I find it hard to believe it's now in this condition from changing a ride height sensor.

Pease let me know your thoughts on:

1. Could a crappy Chinese ride height sensor knock all the sub systems out?
2. Would the ABS sensor or any other wires that I might have accidentally knocked around take out the entire can bus system? Could I just check ABS sensors out put on the Gap IID tool? IS there value in this if the car isn't moving and not running?
3. How would I even go about checking the resistance on that huge bundle of wires in the passenger channel
4. How would I jump the starter relay. I'm curious if it would turn over. Maybe this isn't the most useful thing to do, but it might give me a small amount of hope.
5. One thing I considered is that I did use the parking brake when doing the repair. I'm not certain but it seemed I couldn't electronically take it off just because of the can bus issue. Could a fault switch cause no starting? I tried latching and unlatching it with Gap IID but I'm unclear if it's working. When latching, I get a "parking brake fault", when mounting I get "engine system fault" and it beeps. I'm not super worried about the parking brake right now, but since I manually disengaged it, does that mean I have to somehow manually re-engage it? I've seen people opening the box up and manually adjusting it, but again I cant see why it won't start due to an parking brake fault.
6. Does anyone know the order of the can bus system and could I maybe hone in on the modules I should look at by the fault codes? The majority of the codes are: U0100-87 (2F) Lost communication with engine control module/powertrain control module 'A' - Bus signal/message failure - missing a message
7. Has anyone experienced this type of water intrusion and replacing the Central Junction box fixed the issues? It didn't seem obvious to me that water would have dripped on it. I'd like to take it out but I fear having to put it back in. Also, wouldn't a used one need to be reprogrammed? Would it be worth my time to pull and check all those fuses down there?
8. Does anyone have ideas about maybe using the Gap IID to more easily discover the issue like perhaps live values or something?
9. Ive seen a lot of steering angle/yaw posts but again can't imagine it wouldn't start.
10 If the majority of faults are from Loss of communication to Engine Control Module do I assume it's the module prior to it on the can bus or the ECM itself. Or the Central Junction Box perhaps? Where on the can bus map does the ECM sit?

Sorry for all the questions, but I'm really trying to think my way through this. Also, I think there is a chance I could be using the Gap IID better. FYI, it seems to not have any problem reading faults or getting live values.

Here are my faults. As you can see, they are mostly U0100-87 communication faults.

Airbag
B1A55-14 (AF) Crash record output circuit - General electrical failure - circuit short to ground or open
( on 30-03-2027 14:56:21 at 295544 km )

Steering Angle
Hex bits: 0010, 1111
U0122-87 (2F) Lost communication with vehicle dynamics control module - Bus signal/message failure - missing a message
( on 30-03-2027 14:56:36 at 295544 km )

Suspension
Hex bits: 0010, 1111
U0100-87 (2F) Lost communication with engine control module/powertrain control module 'A' - Bus signal/message failure - missing a message
( on 30-03-2027 14:56:36 at 295544 km )

Terrain Response
Hex bits: 0010, 1111
U0100-87 (2F) Lost communication with engine control module/powertrain control module 'A' - Bus signal/message failure - missing a message
( on 30-03-2027 14:56:33 at 295544 km )

Transfer Case
Hex bits: 0010, 1111
U0100-87 (2F) Lost communication with engine control module/powertrain control module 'A' - Bus signal/message failure - missing a message
( on 30-03-2027 14:56:36 at 295544 km )

Transmission
Hex bits: 1010, 1111
U0100-87 (AF) Lost communication with engine control module/powertrain control module 'A' - Bus signal/message failure - missing a message
( on 30-03-2027 14:56:33 at 295544 km )

My current plan is to maybe unhook rear lights, check ABS live values once battery is back in, check battery voltage when it's off the charger (decide if I want to spend $200 on a new one), depending on any replies get, maybe removing the fuses at the Central Junction Box and testing resistance or possibly removing the whole thing to inspect and just deal with putting it back, I am considering pulling get ECU since the battery is out already and inspecting it the way I did the TCCM.

Thanks for any of your thoughts and ideas!
Jeremy

 

Water getting in from the cowl will hit the CJB. But one instance shouldn't cause a failure.

Since you have a gap tool, I'd do a vehicle reset with it and try starting again.

 

I've done multiple hard resets, soft resets with the Gap tool, and Fault clearing, and each time they come back immediately when I turn the key to the On position. Is there another reset you are referring to?

 

Can you jump start it with the ground cable from the starter connected to the car body rather than the battery?

Compare the voltage between the positive and negative posts on the battery. Then check between the positive terminal and the body and notice the difference. Chances are that the battery is weak and ground cable is bad.

Connect the positive cable from the starter to the positive terminal of the battery and the negative cable from the starter to a good ground lug and try to start it.

Jeff

 

Battery just charged over night and is now reading a good 12.7v. I'll likely try it soon, but I'd still fee like the battery and/or ground cable happen to suddenly go bad right after the ride height repair, but you never know!

I guess I am a little confused on your suggestions.

Sentence 1: I'm unclear what moving the starter negative cable to car body accomplishes. Maybe you are assuming a jump start where the negative from power source is on ground and not battery terminal? Ive tried a lithium jump starter directly to the battery with no affect.

Sentence 2: I think you are simply saying check voltage difference between battery terminal versus body (and nothing to do with your first suggestion right?)

Sentence 3: Are you suggesting that I first remove the Starter neg from battery, move the starter's positive cable to directly to battery, then touch the negative to a good ground?

All of which might be difficult since it's currently slammed to the ground because I cant charge the air suspension reservoir.

 

Hi All,

I just went through the Can Bus Diagrams. Assuming I have an electrical problem from either the repair or the water I was hoping I could "trace back" to see where faults were starting. Some modules downstream give no faults like Rear Differential Control (maybe this is locking diff which I dont have?). First one on the list is Instrument Cluster of which I have no faults, then I get the majority of modules going down the line of the High Speed Can Bus. Item 13 in the diagram is not identified for some reason. If I understand correctly, the Can Bus system is communication serially and through some of these modules (some are off-shoots). If I get no instrument cluster faults then maybe a bad connection to instrument panel? Does anyone know How this High Speed Can Bus, the Engine Control Module, and Central Junction Box interact?

I see ECM is connected directly to CJB but I don't see how it or the CJB is then connected to instrument cluster or any other modules in the HS Can.

Jeremy

 

One thing it could be is the ground strap. They're notorious for rotting and getting loose at the body connection and causing electrical issues.

Basically trace the negative cable from your battery to the ground point and make sure it is solidly bolted down and there's no rust or corrosion at the ground.

 

Looking at the codes I'd guess there may be an issue with the "Airbag B1A55-14 (AF) Crash record output circuit - General electrical failure - circuit short to ground or open
( on 30-03-2027 14:56:21 at 295544 km )"
Having used the GAP Tool to diagnose a couple issues on my LR3, I've found that you have to look through the codes/information and figure out what code is causing the problem and which ones are the result of that problem. I'm guessing there is an issue with the airbag wiring, restraint control module or something along those lines and that fault is stopping/altering communications with the modules causing a limp mode or in your case, go nowhere mode. I'm assuming there is no warning lamp on the gauge cluster? Let us know what you find...

 

Update: I think I have several things going on. 1) Water ingress was an issue but I hope it hasn't been or will be the cause of further problems. It rained hard today and I see no further water in the cabin after sealing off the fresh air intake. 2) I was suspect of the airbag fault after I inspected the fuses and which systems were not getting power wondering if it was in a fail state. Couldn't find any obvious wiring issues with that. May still be a problem but also could be part of the cascade.

No power to fuses under the hood:
F3 Air Suspension ECU
F1 Fuel Pump
F17 Petrol EMS injectors

which led me to consider the ECM as the generally are controlled by the ECM relay, but I am now thinking that it's tripped up by the suspension module which is receiving the following:

3) I used Gap IID to look at live values and there is a high voltage on the rear ride height sensor (the one I repaired), thus I am circling back to that repair and what is causing this. I figure it is either a short, or cross-wired situation and have a new ABS sensor and ride height sensor harness in hand. Will have to examine all the wires that go to these and see if there is a pinch or open wire to ground or another positive to positive short.

Hope I can find it and that the water ingress was just an additional (but hopefully not a problem) situation.

 

Lots of lights and faults but there is a chance, without knowing the wiring locations, that somehow the ride height sensor is crossing a crash sensor in the drivers rear. Something is tripping up the ride height sensor provided voltage. Could be linked. Got to be some sort of short down there.