reprogramming, mdi2 and SPS-2 questions

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lesmiserah

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I do most of my friends and family's car repairs but have no formal training. My uncle has a 2011 Yukon hybrid that's gone stupid on the hybrid side. He took it to the dealership who diagnosed with a bad Drive motor inverter. As a new one was like 6k we opted to get a used off ebay and the dealership agreed to install it with no warranty on the work. They installed it but said it could not be programmed but were rather vague on why. The ebay seller (with 8k reviews at 99.3% positive) took it back and paid for the return shipping. He told me he pulled it himself and there were no problems. The seller seems on the up and up but i've never really had a good experience with a dealership so I've been reading and I need some clarifications on whats what.

I was look at this. https://www.vxdas.com/products/gm-mdi2?variant=20017224089673

I comes with GDS2, Tech2 Win Software. ACDelco has the software as a subscription, does this just save me the download and I still have to subscribe or is it good to go as is. If it's good i just need a subscription to SPS-2 and I can reprogram everything myself if I am understanding correctly? Dealership's already charged $2k in service and he is still effectively where he started.
 

j91z28d1

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interested to know what you learn about flashing modules as I'm no help there, but sure I'll need to do it at some point.

is the truck still at the dealer? being willing to work on stuff yourself, if you have the codes it's throwing, might be able to look up the trouble shooting list, at least it would confirm its a bad module as I don't trust dealers to tell the truth. I wouldn't be surprised if they swapped it, flashed it and had the same problem, then just wanted to get it out the door as simpler less time consuming, more profitable cars to be fixed(flat rate wise). so the service writer just says whatever he feels like is believable.
 
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lesmiserah

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I'm fairly certain the hybrid computer. He called me from out of town and said his car shutdown with "engine power reduced error", checked the codes and there was a crankshaft position sensor fault. Ended up changing that in a parking lot and clearing codes. Drove 5 minutes and the same thing happened. One thing after another started failing. By the end of day half the sensors were returning faults, the timing was screwed up and the car would only start for 10 seconds, run super rough then stall out. Everything I read lead me to the ECM so we took it to a Tech shop who confirmed bad computer but they were not able to work on the hybrid side so it ended up at the dealership. And yea, I don't trust them at all. They called my uncle and confirmed it was the computer but then asked for another 5 hours of diagnostic time. I dont know what they did and I cant check on their work unless I can find a way to interact with the hybrid system directly.
 

Fubar0715

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I originally purchased the Tech2 in hopes of "turning on" features on my SSV but could not get it to work in a way I could update modules or communicate with anything from a programming perspective. Took a step back and bought a VX diag module that worked with a laptop and after quite a bit of trial and error, I was able to get it working. I have used it to "update" the various existing modules in my truck using the laptop. I still use the Tech2 (recent key fobs adds) and will troubleshooting an airbag list when it warms up here. Let me know if you have questions!
 

j91z28d1

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I'm fairly certain the hybrid computer. He called me from out of town and said his car shutdown with "engine power reduced error", checked the codes and there was a crankshaft position sensor fault. Ended up changing that in a parking lot and clearing codes. Drove 5 minutes and the same thing happened. One thing after another started failing. By the end of day half the sensors were returning faults, the timing was screwed up and the car would only start for 10 seconds, run super rough then stall out. Everything I read lead me to the ECM so we took it to a Tech shop who confirmed bad computer but they were not able to work on the hybrid side so it ended up at the dealership. And yea, I don't trust them at all. They called my uncle and confirmed it was the computer but then asked for another 5 hours of diagnostic time. I dont know what they did and I cant check on their work unless I can find a way to interact with the hybrid system directly.


ouch so the engine ecm had issues and needed replaced too. man that's some bad luck. these have a odd ball ecm too from what I remember. 67A or something. probably wasn't easy to find.


but that solved all the sensor issues on engine side?
there's a tsb somewhere about grounds on some gm cars and trucks, and these were included in the years I believe. so much. going wrong all at one always makes me think grounds.

hopefully you get it fixed. only down side to these trucks is it even if it's a simple repair, jumping thru hoops with shops and dealers make it feel like a nightmare.

I can't find the grounds tsb, I thought I had it saved. but if you don't have it, this might help with the diagnosis process for the hybrid stuff. I believe it's posted here in other threads too.
 

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lesmiserah

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Soo... Now that it's warmer I've gotten back around to this months later. Uncle ended up getting a different vehicle. We told the dealership we were going to hold off on any more work and take the yukon home for now. We got it back in pieces, the inverter was in the back seat, air intake and other bits scattered around. All the nuts and bolts laying around the floor and engine compartment. Cover plates on the inverter missing and never were found, dealer was supposed to order replacements but never heard from him. One of the bottom plates that shouldnt have been removed was and gasket was sticking out the side with only 2 of 6 screws in holding it together.

Took a while but I got everything back together minus the cover plates that go over the power connectors. I got the vcx Nano, A sub to SPS2 at acdelco and tech2 up and running after about 4 hard drive reformats and a lot of trial and error. I did the sequential reprogramming, it finished all the modules without error. Hit the key and nothing has changed. She started once for about 2 seconds but barely and stalled back out. Hit the key again and it just kind of made a grunting noise and did nothing. I've got more error codes than I know what to do with and no idea where to start. On the plus side the dashboard no longer says service hybrid system but it does say Service Stabilitrak, traction control and power low: start vehicle, which I would LOVE to be able to do. Lol The 12v battery was full when I reconnected it but then there is a high pitched whine under the hood and it drains the batter in a matter of minutes. I'd guess it's trying to recharge the HV battery off the 12v? It doesn't do it instantly every time but after sitting there a bit with the key on it will randomly start whining and draining the 12v. I left it on the charger over night and I'll see what I'm ready to face today. Needless to say I'm a bit over my head here but I am learning.

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lesmiserah

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lesmiserah

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Hybrid battery pack 236v
Hybrid battery terminal 12.8v
Hybrid battery 1-20 range from 13.5v to 11.2v
Hybrid battery SOC 58%
contactor sys req ckt 70%
 

BG1988

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Hybrid battery pack 236v
Hybrid battery terminal 12.8v
Hybrid battery 1-20 range from 13.5v to 11.2v
Hybrid battery SOC 58%
contactor sys req ckt 70%
Check the transmission for a backed out harness connector or damaged harnesses at the brake peddle area let me get the TSB for it

There is also a large harness connector on the HV battery inspect pins for corrosion ...
 

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BG1988

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ouch so the engine ecm had issues and needed replaced too. man that's some bad luck. these have a odd ball ecm too from what I remember. 67A or something. probably wasn't easy to find.


but that solved all the sensor issues on engine side?
there's a tsb somewhere about grounds on some gm cars and trucks, and these were included in the years I believe. so much. going wrong all at one always makes me think grounds.

hopefully you get it fixed. only down side to these trucks is it even if it's a simple repair, jumping thru hoops with shops and dealers make it feel like a nightmare.

I can't find the grounds tsb, I thought I had it saved. but if you don't have it, this might help with the diagnosis process for the hybrid stuff. I believe it's posted here in other threads too.
i got the PDF files on the ground wire locations most of them are on the frame rail..
 

j91z28d1

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man you're definitely in deep.

over my head too, but what was the mileage and year of the battery pack before all this stated?

236v sounds crazy low. how are you getting that voltage? from the scanner or from a volt meter at the pack. I'd check at the pack with a volt meter and see if they match. my pack is like 320v.

the under hood inverter cover has a jumper on it. since it's missing, need to jump that with something for it to start.

the under hood noise that kills the 12v. can you find out what that noise is coming from? that's sounds bad. is the battery getting hot from the high drain?

I can look up some wiring diagrams for you if you have something specific you need to check, but also for like 30$ you can buy a one vehicle access on the nonpro side of prodamand software. gives trouble trees to follow and research for each trouble code you have. it should atleast help get a handle on how the system works.

with the scanners you have, you should be able to do jump assist mode, that's where you put a battery charger on the 12v and it puts it in a mode that tries to charge the hybrid battery. it won't do that without using the scanner. I've not done it, but it's a bit of drawn out process.
 
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lesmiserah

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I got the voltages threw from the battery control module with Tech2. I believe its the original battery from 2011 with 200k miles on it. Some other things that i've learned. Tech2 has real time monitoring of the battery voltage. So with the HVBattery at 233v and the 12v at 11.8 with 3 percent charge I left the charger on over night. When I work up they were at 336v and 12.4 at 57%. A few hours later at 339v and 89% I turned the ignition key on. The box next to the 12v battery and radiator began to hum and the 12v battery began to lose charge. I checked it a few minutes later and they were at 248v and 12v was at 4%

I disconnected the battery, charged the 12v 80%, reconnected it and hit the ignition. The car rolled over and fired maybe 4 times then stopped. I checked and it had dropped back to 331v and 12v 40%. The 12v batter loses no charge when not hooked up to anything. it sat around unhooked for a month with no noticeable loss. I have not directly stuck a multi meter on the battery itself though.

Here is the read out for the battery
 

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