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Discussion Starter · #1 ·
I late August started having my VDC and ABS show up intermittently upon startup. Typically a quick restart would clear the lights and they never appeared after startup while running. Amazingly the truck didn't heal itself and within 2 weeks it was happening at nearly ever startup and could not be cleared, so off to the shop it went.

U1000 ABS, U1001 ECM, and P0717 Turbine reverse sensor.

They did the basic cleaning of the connectors and looking for wiring faults, but nothing was found. It was recommended that I go to a shop that specializes in electrical troubleshooting.

Before making that appointment I did some digging and found an old bulletin about the grounding lugs causing the U100X codes so I went through all of the engine bay grounds and gave them a good brushing and reassembly with dielectric grease. I also had my battery warrantied, as it was a little low on CCAs. I tested the CAM buss to make sure it showed the correct resistance and it did.

These steps improved the situation and the issue went back to being more intermittent and could usually be cleared, but it did not solve the issue. I was pretty sure it was a ground issue somewhere, but I could not locate it. So I made an appointment with the electrical shop.

They went through the codes and the wiring diagrams and everything kept pointing to the issue being in the trans control, t-case control, or the wiring between them. Due to the history of SMOD with these trucks all of the troubleshooting guides pointed to it, obviously, being a SMOD issue that someone tried to hide. I knew this wasn't the case since I've owned it from new, replaced the rad at 80k, and replaced the tranny fluid every 30k. But the techs insisted that the tranny pan needed to be dropped and inspected.

Out the TCM came and tada, no SMOD.

Back to point to point testing and o-scope testing of the module boot processes. Everything was still indicating that the issue was between the tranny and tcase, but the wiring and computers all checked good.

During this time I found that I could usually prevent the lights from coming on if I held at "ON" for a second before actually starting the truck, but not always.

At this point it needed hooked to that actual Nissan Consult to see what the CAN Bus was actually transmitting. After a few hours the tech came back and said it had the U1000, U1001, P1808M, P1817, and P1819 codes stored, but nothing was active and they could not replicate the issue. In the parking lot immediately after I had the conversation with the tech the lights came up upon startup. I walked back inside and told them the lights were on and for them to go back in.

This time, after several hours of searching, the tech found another code, P1856, a diff lock error. He pulled the plug, cleaned it out, and reassembled.

I have not had any error lights in 5 days.

Between 6 trips to 3 different shops it cost about $900 to find that my diff locker plug was dirty and get it cleaned.

So if you get U1000 and U1001 clean all your grounds and every driveline connector before you take it to a shop.

1 Posts
Have exact same three main codes and no check engine light (at all). I suspect TCM as I did have the coolant issue, but I will check all grounds and connections first. There is a Nissan Tech Bulletin regarding the grounds. Thanks for the info.
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