Nanocom Short. OBD2 + Transmission Issues
Nanocom Short. OBD2 + Transmission Issues
Not 100% sure if they are related but heres the story.
With the engine running, I plugged in the nanocom to the connector (NOT at the OBD2 port, but rather the screw in plug that connects the nanocom to the cable), and I see a small spark and the nanocom shuts off. Suddenly the radio stops working (aftermarket, but loses power), my interior lights won't work, unlocking/locking via the key stops working, and the OBD2 port doesnt work (tried to plug in an ultra gauge and it didn't light up or show anything.
Things I've tried: Checked all of the fuses in the engine bay fuse box, and the fuse box under the steering wheel.
Around the same time (within 20 miles of the short to when I started to notice) my transmission won't properly engage from 0mph to 5-10mph on level ground. I can still move forward but its slow and I have to give it a lot of throttle. If I'm already moving or at a slight incline it seems to work fine. Reverse gear works just fine.I checked the transmission fluid level and it seems to be 2.5 quarts low. I fill it up, go for a test drive and it seems slightly better, but likely placebo. I hop on the highway to leave for a trip and realize the transmission won't shift into 4th gear. All the other gears seem to shift fine. It may be important to note that I did dent the transmission pan in, which reduced the volume of the pan by about 1 quart. Ran fine and replaced the pan + fluid back in October. Haven't had any issues at all besides this. Talking with local D2 owners, one pointed out that 4th gear could be an overdrive gear, controlled electronically. Which could be affected by the short.
My theory is that I shorted something either within the ECU, or there a grounding issue somewhere. Which could be related to the transmission issue. The car works just fine other than this.
I'm not entirely sure where to proceed with this. I haven't checked the ECU ground or taken it out yet, but not sure if I should check anything else.
With the engine running, I plugged in the nanocom to the connector (NOT at the OBD2 port, but rather the screw in plug that connects the nanocom to the cable), and I see a small spark and the nanocom shuts off. Suddenly the radio stops working (aftermarket, but loses power), my interior lights won't work, unlocking/locking via the key stops working, and the OBD2 port doesnt work (tried to plug in an ultra gauge and it didn't light up or show anything.
Things I've tried: Checked all of the fuses in the engine bay fuse box, and the fuse box under the steering wheel.
Around the same time (within 20 miles of the short to when I started to notice) my transmission won't properly engage from 0mph to 5-10mph on level ground. I can still move forward but its slow and I have to give it a lot of throttle. If I'm already moving or at a slight incline it seems to work fine. Reverse gear works just fine.I checked the transmission fluid level and it seems to be 2.5 quarts low. I fill it up, go for a test drive and it seems slightly better, but likely placebo. I hop on the highway to leave for a trip and realize the transmission won't shift into 4th gear. All the other gears seem to shift fine. It may be important to note that I did dent the transmission pan in, which reduced the volume of the pan by about 1 quart. Ran fine and replaced the pan + fluid back in October. Haven't had any issues at all besides this. Talking with local D2 owners, one pointed out that 4th gear could be an overdrive gear, controlled electronically. Which could be affected by the short.
My theory is that I shorted something either within the ECU, or there a grounding issue somewhere. Which could be related to the transmission issue. The car works just fine other than this.
I'm not entirely sure where to proceed with this. I haven't checked the ECU ground or taken it out yet, but not sure if I should check anything else.
Last edited by rikkd; Feb 18, 2025 at 04:39 PM.
Rock Crawling
Joined: Jun 2021
Posts: 271
Likes: 63
From: California
Check the fusible links in the engine compartment too. You might need a multi meter for them. Also double check that all the fuses are the correct amperage. If some are not, its possible something else became a "fuse" and burned.
Fusible links? Are they in the fuse box or elsewhere? I checked everything in the fusebox and all of them are stock/factory and haven't been altered. I'm planning on double checking all the grounds soon. I had another weird thing where my off-road lights were flashing in the middle of the night during a rainstorm. I think water got into the relay or the ground became loose. That was 2 weeks ago though, and after taking out the relay and putting it back its been fine.
Oh also, I think I can rule out battery issues, as It was driven daily and has a solar panel on the roof constantly charging it. Moved it today and it started up no problem.
Oh also, I think I can rule out battery issues, as It was driven daily and has a solar panel on the roof constantly charging it. Moved it today and it started up no problem.
Rock Crawling
Joined: Jun 2021
Posts: 271
Likes: 63
From: California
These are the fusible links in the engine bay fusebox. I forgot they were clear on the top, so you probably already checked them. If you haven't already, try unplugging the battery, connecting the terminals on the car, and plugging the battery back in. There could by some kind of power trip switch somewhere.
TReK
Joined: Sep 2020
Posts: 2,957
Likes: 754
From: British Columbia Canada
I don’t know if this is a thing on D2’s, but on P38’s you need to plug the connector into the Nanocom before you plug it into the OBD2 port. If you do it the other way around you blow a relay. I don’t know which relay as it hasn’t happened to me yet. Hopefully it’s as easy as replacing a relay.
As for the shifting issue, it may be related, but maybe not. The 2 most common causes seem to be incorrect transmission servicing, or bad voltage. Just because your battery is new and seems to be fully charged doesn’t necessarily mean it is. And checking the transmission fluid level must be done per the book. Hopefully the fix will be simple and cheap.
As for the shifting issue, it may be related, but maybe not. The 2 most common causes seem to be incorrect transmission servicing, or bad voltage. Just because your battery is new and seems to be fully charged doesn’t necessarily mean it is. And checking the transmission fluid level must be done per the book. Hopefully the fix will be simple and cheap.
I don’t know if this is a thing on D2’s, but on P38’s you need to plug the connector into the Nanocom before you plug it into the OBD2 port. If you do it the other way around you blow a relay. I don’t know which relay as it hasn’t happened to me yet. Hopefully it’s as easy as replacing a relay.
As for the shifting issue, it may be related, but maybe not. The 2 most common causes seem to be incorrect transmission servicing, or bad voltage. Just because your battery is new and seems to be fully charged doesn’t necessarily mean it is. And checking the transmission fluid level must be done per the book. Hopefully the fix will be simple and cheap.
As for the shifting issue, it may be related, but maybe not. The 2 most common causes seem to be incorrect transmission servicing, or bad voltage. Just because your battery is new and seems to be fully charged doesn’t necessarily mean it is. And checking the transmission fluid level must be done per the book. Hopefully the fix will be simple and cheap.
I plugged the OBD2 port first, and then the connector to the nanocom. I'll look at that next! I did do the transmission service myself, and I'm by no means an expert at it. but I'll check the level this weekend.
@evil_goat I did check those and they appear to be in good shape!
TReK
Joined: Oct 2007
Posts: 2,776
Likes: 1,985
From: Whidbey Island, PNW
This is a good one. Disco truly being a Disco. Sparks from the OBD2 port. How ridiculous. It’s one of those posts that people read when researching buying a Disco and then they are scared off and never buy a Land Rover. (I love that hahaha!). I would say your issues, looked at holistically including the driving lamps flashing in the night in a rainstorm is all 100% related. Seems appropriate that the car is named “Wicked Witch” isn’t it?
Q: Are your M&S lights on and the check engine light? (that would indicate the car is in limp mode which means you are starting in 3rd gear which might explain the transmission thing, by the way?
1) Are you getting water into the interior of your car? This sounds an awful lot to me like the bat**** things that defy any “by the book” troubleshooting start to happen when you get water into either your interior fusebox under the drivers side steering wheel (which you have looked at) but often the water is inside the grey plastic case and only evident if you remove the fuse box -- or -- inside the BCU or BCU connectors over on the passenger footwell area,. And you mentioned rainstorm, on a California car, which .. well it leads me to believe water ingress may be happening. This is when a Disco 2 starts behaving like a P38.
2) Yes, it could be fusible links -- in the underhood fuse box. But, Then the question is ... why would they blow and that points right back to #1 for me.
The common links between interior lights, radio, door locking/unlocking & OBD port is interior fuse box or BCU. The 1st gear transmission thing has me a bit stumped, I’ll be honest, but if the Transmission ECU was also waterlogged or the connectors are corroded, crazy things could happen. And that transmission ECU (TCU is under the drivers seat, which is unlikely to be soaked -- but -- maybe the wiring to it or signal to it is f-cked. Even if you don’t see water on top of the carpets, you’d be surprised... Do a thorough look. Once BCU gets wet, all bets are off.
I had an interior fusebox get corroded a few years ago and my 2000 Discovery 2 acted like it was literally possessed by demons. Nonsensical things were happening.
The water ingress would be the most simple explanation for this.
Q: Are your M&S lights on and the check engine light? (that would indicate the car is in limp mode which means you are starting in 3rd gear which might explain the transmission thing, by the way?
1) Are you getting water into the interior of your car? This sounds an awful lot to me like the bat**** things that defy any “by the book” troubleshooting start to happen when you get water into either your interior fusebox under the drivers side steering wheel (which you have looked at) but often the water is inside the grey plastic case and only evident if you remove the fuse box -- or -- inside the BCU or BCU connectors over on the passenger footwell area,. And you mentioned rainstorm, on a California car, which .. well it leads me to believe water ingress may be happening. This is when a Disco 2 starts behaving like a P38.
2) Yes, it could be fusible links -- in the underhood fuse box. But, Then the question is ... why would they blow and that points right back to #1 for me.
The common links between interior lights, radio, door locking/unlocking & OBD port is interior fuse box or BCU. The 1st gear transmission thing has me a bit stumped, I’ll be honest, but if the Transmission ECU was also waterlogged or the connectors are corroded, crazy things could happen. And that transmission ECU (TCU is under the drivers seat, which is unlikely to be soaked -- but -- maybe the wiring to it or signal to it is f-cked. Even if you don’t see water on top of the carpets, you’d be surprised... Do a thorough look. Once BCU gets wet, all bets are off.
I had an interior fusebox get corroded a few years ago and my 2000 Discovery 2 acted like it was literally possessed by demons. Nonsensical things were happening.
The water ingress would be the most simple explanation for this.
This is a good one. Disco truly being a Disco. Sparks from the OBD2 port. How ridiculous. It’s one of those posts that people read when researching buying a Disco and then they are scared off and never buy a Land Rover. (I love that hahaha!). I would say your issues, looked at holistically including the driving lamps flashing in the night in a rainstorm is all 100% related. Seems appropriate that the car is named “Wicked Witch” isn’t it?
Q: Are your M&S lights on and the check engine light? (that would indicate the car is in limp mode which means you are starting in 3rd gear which might explain the transmission thing, by the way?
1) Are you getting water into the interior of your car? This sounds an awful lot to me like the bat**** things that defy any “by the book” troubleshooting start to happen when you get water into either your interior fusebox under the drivers side steering wheel (which you have looked at) but often the water is inside the grey plastic case and only evident if you remove the fuse box -- or -- inside the BCU or BCU connectors over on the passenger footwell area,. And you mentioned rainstorm, on a California car, which .. well it leads me to believe water ingress may be happening. This is when a Disco 2 starts behaving like a P38.
2) Yes, it could be fusible links -- in the underhood fuse box. But, Then the question is ... why would they blow and that points right back to #1 for me.
The common links between interior lights, radio, door locking/unlocking & OBD port is interior fuse box or BCU. The 1st gear transmission thing has me a bit stumped, I’ll be honest, but if the Transmission ECU was also waterlogged or the connectors are corroded, crazy things could happen. And that transmission ECU (TCU is under the drivers seat, which is unlikely to be soaked -- but -- maybe the wiring to it or signal to it is f-cked. Even if you don’t see water on top of the carpets, you’d be surprised... Do a thorough look. Once BCU gets wet, all bets are off.
I had an interior fusebox get corroded a few years ago and my 2000 Discovery 2 acted like it was literally possessed by demons. Nonsensical things were happening.
The water ingress would be the most simple explanation for this.
Q: Are your M&S lights on and the check engine light? (that would indicate the car is in limp mode which means you are starting in 3rd gear which might explain the transmission thing, by the way?
1) Are you getting water into the interior of your car? This sounds an awful lot to me like the bat**** things that defy any “by the book” troubleshooting start to happen when you get water into either your interior fusebox under the drivers side steering wheel (which you have looked at) but often the water is inside the grey plastic case and only evident if you remove the fuse box -- or -- inside the BCU or BCU connectors over on the passenger footwell area,. And you mentioned rainstorm, on a California car, which .. well it leads me to believe water ingress may be happening. This is when a Disco 2 starts behaving like a P38.
2) Yes, it could be fusible links -- in the underhood fuse box. But, Then the question is ... why would they blow and that points right back to #1 for me.
The common links between interior lights, radio, door locking/unlocking & OBD port is interior fuse box or BCU. The 1st gear transmission thing has me a bit stumped, I’ll be honest, but if the Transmission ECU was also waterlogged or the connectors are corroded, crazy things could happen. And that transmission ECU (TCU is under the drivers seat, which is unlikely to be soaked -- but -- maybe the wiring to it or signal to it is f-cked. Even if you don’t see water on top of the carpets, you’d be surprised... Do a thorough look. Once BCU gets wet, all bets are off.
I had an interior fusebox get corroded a few years ago and my 2000 Discovery 2 acted like it was literally possessed by demons. Nonsensical things were happening.
The water ingress would be the most simple explanation for this.
There was definitely water leaking via the sunroof, but I cleaned all of it up. It only appeared to get the headliner wet. It leaks often and Its my daily so I dry it out every day. The passenger footwell appears to be dry, but I haven't pulled back the panel yet.
Yes! the naming scheme came from naming one of the LR3s Dorothy. We used to have a star wars theme, but over time we developed a new one. Although we often call Wicked Witch the D2, and the LR3s by their respective names. Except the LR4, we just call it the LR4.
TReK
Joined: Oct 2007
Posts: 2,776
Likes: 1,985
From: Whidbey Island, PNW
Bent pins is a good idea actually, good one Extinct!
But also-- you said water is getting in. Bingo.
The water runs behind all the panels - behind headliner, behind a-pillar and dash, behind kick panels, right onto fuse boxes and BCU’s. You’d almost never know it was there and most people don’t. You can have a small stain on the headliner from the sunroofs or roof rails, but that’s enough indication that there could be over time harness and connector/BCU/Fusebox damage down below especially if the leak and water has been happening for years. I’ve seen it many times on D2’s.
At least 50-60 % of D2’s I see in salvage yards have unusable drivers side fuseboxes from water ingress corrosion, FYI. I pull every one I see in hopes it may be a good spare since they are NLA. It’s not rare. BCU’s far less. 10%-20%? Plastic wire connectors near BCU - more likely.
Good luck, Sounds like you’re well on the hunt to resolution.
But also-- you said water is getting in. Bingo.
The water runs behind all the panels - behind headliner, behind a-pillar and dash, behind kick panels, right onto fuse boxes and BCU’s. You’d almost never know it was there and most people don’t. You can have a small stain on the headliner from the sunroofs or roof rails, but that’s enough indication that there could be over time harness and connector/BCU/Fusebox damage down below especially if the leak and water has been happening for years. I’ve seen it many times on D2’s.
At least 50-60 % of D2’s I see in salvage yards have unusable drivers side fuseboxes from water ingress corrosion, FYI. I pull every one I see in hopes it may be a good spare since they are NLA. It’s not rare. BCU’s far less. 10%-20%? Plastic wire connectors near BCU - more likely.
Good luck, Sounds like you’re well on the hunt to resolution.