2008 G35 U1000 DTC & Others Seems Like They Are Related HELP

Post by **DRoush** » Wed Aug 11, 2021 8:02 pm

Just bought this G for my son and it passes all the power train DTCs and freeze frame ones. However it has DTCs that my scanner app for Innova says need attention. Has anyone dealt with this U1000 code before. All the codes stored seem to relate to lost communications faults. I have these codes shown on the attachment.

: Codes

HELP

Post by **VStar650CL** » Thu Aug 12, 2021 4:24 am

Those codes are all indicative of a low-battery incident sometime in the car's past. When the battery goes below about 8.5V, the CANbus on N/I cars starts to drop out. That generates all sorts of spurious malfunction codes. Try erasing them and see which (if any) return. U1000 is a generic CANbus code which means the unit in question hasn't heard an expected communication from some other unit for more than 2 seconds. The code won't tell you which unit, so you need to consult the LAN section of the SM to see what units are supposed to be checking in with the unit that threw the code.

Post by **DRoush** » Thu Aug 12, 2021 10:23 am

Thanks for the reply. I had erased all the codes and these came back. I know the battery looks old but being I just bought this used car I am not sure how old. I can check the voltage with a load test. Could it just be the battery and the ground to the body from the negative cable? I was going to do this first and erase codes and check again. Thoughts? If not you say check the SM and I assume you mean service manual, so it will tell me what ones should be checking in. Ok that makes sense but any idea how to narrow it down? I am sure these modules are pricy and may need programming. I have a Innova scanner. I believe it is a 5410 model but not in front of me right now. It has technical bull items on it. Maybe a flow chart to check modules would be in.

Post by **VStar650CL** » Thu Aug 12, 2021 12:41 pm

U1000 usually means there's a system that's completely MIA on the bus, often just from a blown fuse. There's a chart in the LAN section showing which system transmits each critical parameter and which systems receive it.
Go through the "receive" column for each of the systems throwing the U1000 and see which systems transmit to it. When you find a common transmitter to all the U1000 receivers, that will be your MIA.

Post by **DRoush** » Thu Aug 12, 2021 1:09 pm

Ok so not a battery. I knew it wouldn’t be that easy. Ok need to get a manual or is there a link on line? Thanks for your help. Much appreciated and I am sure I will have more questions.

Post by **DRoush** » Thu Aug 12, 2021 1:15 pm

Also what about the other codes. Do you think they are related or do I need to start with this U code and go from there? Sorry not really familiar with this car or the scanner codes.

Post by **VStar650CL** » Thu Aug 12, 2021 3:22 pm

Chances are all or many of the other codes are derivative. Get to the bottom of whoever is MIA and you'll probably fix those too. There's a pretty complete set of ESM's right here, just go to the top of any page and hit the "Service Manuals" link on the top bar.

Post by **DRoush** » Thu Aug 12, 2021 4:09 pm

Found them and marked all the transmitters for each system throwing a “U” code. I am assuming that if it starts with a “U” I should check what module it transmits to. So did the Awd/4WD,Multi Av Nav, and the Precrash Seatbelt. If this correct please let me know. The all transmit to M&A or what they call unified meter and A/C amp. Am I on the right track? If so should I see if there is a fuse to check for that module? Or to I need to OHM it out with a back probe?

Post by **DRoush** » Thu Aug 12, 2021 4:12 pm

This club and forum is great. SM on the site is handy. Luckily the car is an 08 since that was as high as they went for this G35. Thanks and hope to hear back from you soon. Thanks for all your help.

Post by **VStar650CL** » Thu Aug 12, 2021 4:25 pm

No, you need to mark units that are throwing U codes as receivers, then see who they're supposed to receive from. Then find which transmitters are common to all of the U-throwers. By process of elimination you'll get to the MIA.

Post by **DRoush** » Fri Aug 13, 2021 5:35 pm

So I looked at all the receivers for the three and the transmitter that they all receive from is the M&A transmitter. It is the only one they all have listed as a transmitter. Basically going down each column for the u code throwers and each one of these systems receives from it. Of course there are other ones they receive from but this one is common to them all. Looking at the pages 29 through 32 at the following link. Do u come up with the same?

LAN.pdf

Post by **DRoush** » Fri Aug 13, 2021 5:35 pm

https://www.nicoclub.com/service-manual ... 08/LAN.pdf

Post by **VStar650CL** » Fri Aug 13, 2021 6:40 pm

The bottom of your list is cut off, but it looks like choices for the AWD are very limited, it only expects to hear from the ABS and the cluster (M&A). There are many other systems that expect to hear from those two, so you'd expect U1000's in a lot more systems. That means it's most likely the AWD Controller has a problem. I went through the other DTC's one by one, and none of them are global CAN problems, all but two are local LAN issues. The U1300 and U121E in the AV are both failure of the bit-bang line between the AV and the control panel, with the U121E indicating the problem is a bad line-driver in the AV (AV replacement is indicated by the SM). The B2128 is the same thing but between the driver seat controller and the automatic drive positioner, the seat controller is saying it can't hear the bit-bang from the ADP. B2109 is the IPDM saying the steering lock relay was stuck but isn't anymore, that DTC specifically shows up from low voltage. So does the C1A01, that's the ADAS unit saying there isn't enough drive voltage for the radar.

Here's the thing. The B2109 is PAST, and that means it should have cleared when you tried to erase the DTC's, even if nothing else erased with it. Since it "came back", it means it never actually erased in the first place. That puts us back where we started, they all look like old codes from a low-voltage episode. Something is up with your scanner that it isn't erasing properly.

Post by **DRoush** » Fri Aug 13, 2021 7:27 pm

So is there still issues with AWD controller and AV? What list is cut off? The codes from my scanner? It is a cheap Innova 5410. If so here is the full list. Finally figuring out how to post them properly. My father in law, who is a retired Chevy mechanic, said they are ghosts. He said they can be a pain to track down.

Post by **VStar650CL** » Fri Aug 13, 2021 7:54 pm

Yes, the first screenshot you posted was cut off short. The B2109 should have cleared immediately since it was "past". Since it didn't, I think your scanner isn't doing erasures correctly. I doubt any of those codes represent actual problems, they're artifacts from a past low-battery episode.

Post by **DRoush** » Fri Aug 13, 2021 8:06 pm

Well that is good news. I will try it again with another scanner. This one is new but cheap. Or maybe just operator error well I appreciate all the support. Thanks again!

Post by **DRoush** » Fri Aug 13, 2021 8:14 pm

2008 G35 U1000 DTC & Others Seems Like They Are Related HELP

Re: 2008 G35 U1000 DTC & Others Seems Like They Are Related HELP

Re: 2008 G35 U1000 DTC & Others Seems Like They Are Related HELP

Re: 2008 G35 U1000 DTC & Others Seems Like They Are Related HELP

Re: 2008 G35 U1000 DTC & Others Seems Like They Are Related HELP

Re: 2008 G35 U1000 DTC & Others Seems Like They Are Related HELP

Re: 2008 G35 U1000 DTC & Others Seems Like They Are Related HELP

Re: 2008 G35 U1000 DTC & Others Seems Like They Are Related HELP

Re: 2008 G35 U1000 DTC & Others Seems Like They Are Related HELP

Re: 2008 G35 U1000 DTC & Others Seems Like They Are Related HELP

Re: 2008 G35 U1000 DTC & Others Seems Like They Are Related HELP

Re: 2008 G35 U1000 DTC & Others Seems Like They Are Related HELP

Re: 2008 G35 U1000 DTC & Others Seems Like They Are Related HELP

Re: 2008 G35 U1000 DTC & Others Seems Like They Are Related HELP

Re: 2008 G35 U1000 DTC & Others Seems Like They Are Related HELP

Re: 2008 G35 U1000 DTC & Others Seems Like They Are Related HELP

Re: 2008 G35 U1000 DTC & Others Seems Like They Are Related HELP

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