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Hey all, I have a 2014 c7 auto stingray base. Recently I started the car up and noticed I didn’t have the usual gauge needle sweep and neither screen in the ipc or infotainment lit up. I turned the car off and back on and after a few tries and everything came on like normal. I took the car to the local auto parts store and had the battery tested and no issue with the battery or alt. The gauges/screens worked when I started it for the tech. Turned the car off bought a few small items and came out and it wouldn’t work again. Put it on a obd2 reader and had a bad data received by bcm message. Next I took the car to Chevy because no one in my area will touch a corvette it literally had to go a hour away. The tech at Chevy supposedly checked all the modules minus the dash cluster and most line because he didn’t want to remove any of the dash components. However the Ucodes he was able to pull up were U2098/ U0028/U0029 . The tech at the dealership said it was the gauge cluster had gone out so I sent it off to be rebuilt, the rebuild company called and said the gauge cluster was operating fine, that it turned on and off like it should with zero issues they kept the cluster a few extra days just to make sure it stayed powered up. Everything I’ve read keeps pointing me back to a HMI module having possibly gone out. The car will run and drive like normal, the only issues before any of this was the occasional screen freezing on the infotainment or the back up camera staying locked on the rear, and phones not connecting via usb. Now the car has no gauges either digital or analog, no infotainment, the only sounds I get are door chimes and seatbelt, but everything else works like it should I have heating and cooling controls, the radio screen goes up and down,The battery/ alternator have been tested multiple times now by the dealership and local parts store. Has anyone experienced this or have an idea what it could be.
You either have a bad radio or device like the IPC or Audio Amplifier or a short to ground on the MOST bus...99.999% of indie shops and even dealerships wouldn't know where to start diagnosing this communication issue...a diagnostic shop can fix your Corvette or any other car...an auto electric shop is another option...if the radio sees a short to ground on the MOST line the U2098 sets and the HMIC will set the U0029...if this issue is intermittent you have to shake down the wiring...if you have no electrical diagnostic experience and a DMM find one of these shops...I myself after checking for a short to ground would disconnect the IPC and Amplifier connectors individually and jumper across the MOST line and see if the issue resolves itself...you jumper across the terminals going into and then out of each of these devices...that would be 4 terminals.
Thanks for the feedback, I have a extra radio module , hmi, and dash cluster and a new most wore as well and a loop to bypass, I’ll give that a try, again I appreciate the feedback. It’s been frustrating to work offshore and have a month to think of what the issue could be
The thing is not to think about what it may be but follow a data driven diagnostic approach...I think you should disconnect the radio connector with battery disconnected and look for a short to ground...this will be much harder to find if intermittent...the MOST wiring may be worn through and shorted to ground somewhere...with your DMM set to ohms probe terminal 1 and then 2 to each of those with one lead and the other ohm meter lead to a clean ground...I would use something like the door hinge...you should see "OL" or no continuity...if you see anything other than OL you have a short to ground...your ohm meter should be set to the highest resistance scale when testing....DON'T BE A PARTS CHANGER !!
DTC Descriptor
DTC U2098 00 - MOST Communication Enable Circuit Malfunction
DTC U2098 02 - MOST Communication Enable Circuit Short to Ground
Diagnostic Fault Information
Circuit/System Description
When the ignition is ON, the A11 Radio initializes the Media Oriented Systems Transport (MOST) bus by sending a short 100 ms low voltage pulse on the electronic control line (or MOST control line) connected to all devices contained on the MOST ring. When MOST receive, transmit, or control line faults are detected, transmit/receive messages will not received as expected from the wakeup request. The A11 Radio and the K74 Human Machine Interface Control Module will then perform diagnostics to isolate these MOST faults. If the MOST control line is shorted low to 0 V for excess amount of time, the A11 Radio will set a U2098 DTC and K74 Human Machine Interface Control Module will set a U0029 02 DTC. At this point the MOST bus will be unable to communicate until the shorted MOST control line is repaired.
Conditions for Running the DTC
* The system voltage is between 9-16 V.
* The ignition is ON.
* The Radio is ON.
Conditions for Setting the DTC
* The Radio senses a short to ground on the MOST control circuit.
* A current DTC is set when a MOST control circuit initialization is invoked and the circuit is detected to be pulled low (0 V) for longer than 1 second.
Action Taken When the DTC Sets
Many or all entertainment components may not function properly.
Conditions for Clearing the DTC
The DTC current status is cleared upon a successful MOST control circuit initialization occurs and the circuit is no longer pulled low.
I had the same exact issue and it turned out to be a faulty cluster. Do you have access to a scanner? One will help you pinpoint where the break is in the MOST Bus system. It can still be figured out without a scanner but it will save you time from jumping the MOST Bus wires at every module to find the issue. Shoot me a PM with your number and I'll gladly walk you through it.
Side note, do you have codes in any other module? For instance, a code in the BCM saying incorrect environment identifier of the IPC?
Hey thanks so much for the feed back, so far I’ve had the cluster tested at southern electronics, he said it came back good but just to double check I bought a back up cluster, so far no joy. I did have a U2098, U0028 and a U0029 code, and the only thing the bcm had was from autozone when they ran a scan, it was incomplete data received by bcm. So she’s at the dealership for now, I hope they can confirm the issue.
Hey thanks so much for the feed back, so far I’ve had the cluster tested at southern electronics, he said it came back good but just to double check I bought a back up cluster, so far no joy. I did have a U2098, U0028 and a U0029 code, and the only thing the bcm had was from autozone when they ran a scan, it was incomplete data received by bcm. So she’s at the dealership for now, I hope they can confirm the issue.
Well if you took the car to a dealership for a diagnosis expect it to be there for a while with little to no chance of being fixed !!...and by the way trouble codes are not part numbers.
A very good possibility they won’t find the issue, but they have a better chance than I do with the access to bypass loops and scanners, it out of my scope and I’m aware of that, but one day it will be fixed, being I’ve tried a different ipc and hmi hopefully it is the acm I have all three modules at the dealership with the car.
It took me a little under 3 hours to determine my issue but I've also been wrenching professionally for 20 years and have all the tools and confidence to not accidentally probe the wrong wires or mess up anything. If the right guy is on the job, it shouldnt be hard for the dealer to figure it out.
It took me a little under 3 hours to determine my issue but I've also been wrenching professionally for 20 years and have all the tools and confidence to not accidentally probe the wrong wires or mess up anything. If the right guy is on the job, it shouldnt be hard for the dealer to figure it out.
Having the right "tech" at a dealership that can diagnose something more complex than a light bulb circuit is a STRETCH !!...well let's see if that dealership can figure it out ??
I’m hopeful, but realistic, I have an auto electrical shop in Nashville lined up next if the dealership falls through. I drive boats for a living, I know enough to do basic maintenance and small stuff, I’d rather let someone who knows what they are doing play with it over my guessing haha. But thank you guys for the input, I’m always up to learn something new.
I’m hopeful, but realistic, I have an auto electrical shop in Nashville lined up next if the dealership falls through. I drive boats for a living, I know enough to do basic maintenance and small stuff, I’d rather let someone who knows what they are doing play with it over my guessing haha. But thank you guys for the input, I’m always up to learn something new.
I'd take the car to an auto electric shop first...dealerships only change parts so they will fire the parts cannon if you take it there and it will be expensive...they don't make money diagnosing cars !!
We can finally put this to rest, Dealership called, it was a backed out pin on a harness under the the fuse block under the hood. Everything is back to working
We can finally put this to rest, Dealership called, it was a backed out pin on a harness under the the fuse block under the hood. Everything is back to working
A pin pushed out of the under hood fuse block ??...well let us know if your issue comes back after a few days..I'm VERY surprised they were able to diagnose it !!...can you post a picture of the repair order of what they did ???
We can finally put this to rest, Dealership called, it was a backed out pin on a harness under the the fuse block under the hood. Everything is back to working
A pin pushed out of the under hood fuse block ??...well let us know if your issue comes back after a few days..I'm VERY surprised they were able to diagnose it !!...can you post a picture of the repair order of what they did ??
Definitely will, I’m picking it up in the morning, hopefully it won’t come back in a few days if it does I’ll be sure to let them know you’re the guy to talk too, I’m sure they’d appreciate someone with so much experience and knowledge to reach out too when they get stuck.
Definitely will, I’m picking it up in the morning, hopefully it won’t come back in a few days if it does I’ll be sure to let them know you’re the guy to talk too, I’m sure they’d appreciate someone with so much experience and knowledge to reach out too when they get stuck.
I'd like to know exactly which pin in the under hood fuse block was bad...just to know if they are BS'ing you...THEY are the experts not me...I should be asking them for help !!
Dealerships have a tech line so I highly doubt they would reach out to members on a forum for help but its wishful thinking! If possible, ask to speak to the tech who worked on it and have him explain what he found.
That's the main battery power wire to the cluster. I would ask for that tech to work on your car if you ever find yourself at the dealer again. I'm glad to hear you got it resolved. I drove mine for a week with no cluster or radio so I know the struggle. No cluster didnt bother me but no radio sucked 🤣
Dead gauge cluster/ infotainment
