I have an '08 Yukon hybrid we bought used in 2008, now have 111k miles.
Finally replaced the hybrid and 12v engine battery November of 2020.

So last week had the dash light up like Christmas with the following:
C1209
C1223
C1227
Check ABS, Check Stabilitrack, Service Brake System
My repair place replaced the left rear ABS sensor and changed the oil.
Go to move it and get a loud noise like a jet winding down.
Now got.....
P0A46 P0C17 P1A20 P1AF0 P1AF2
They called Green Bean and gave them these codes and they came and replaced the hybrid battery.
Service was able to clear some of the codes but some wouldn't clear.
I think these are the main ones: P0A46 P1AF0 and P1AF2.
Truck won't start and won't even read codes.
Service is concerned the noise was something breaking loose in the transmission.
Service has researched and found a used 2wd transmission in Nevada with 128k miles.
I think Monday I will have it towed to the GMC dealership where it was purchased.
I kind of miss it when the only issue I was having was the TPS light.

Any thoughts? Concerns? Ideas?

Thanks

 

something High voltage shorted out P1af2 hybrid voltage system isolation fault



you can check all the codes here

11OBDG010 Hybrid(11).xlsx (gm.com)

transmission codes

https://gsi.ext.gm.com/gmspo/mode6/pdf/2013/13OBDG01%20Hybrid%20TCM%20Diagnostics.pdf

 

My local shop has withdrawn from the challenge and the Yukon will be towed to GMC Wednesday.
The current theory is the motor and/or sensor on the #2 drive motor has failed or is damaged.
The position sensor is a non-serviceable part of the drive motor generator.
The sensor
directly attaches to the motor and is only available as a whole unit for the list price of $3100, plus labor.
The availability of a replacement #2 motor is unknown.
My local shop says the GMC dealership has tools and software exclusive to GM which should provide more details to the failure and any resolution.
My goal is at least get a second opinion from GM with some certainty to the problem and solution.
Unfortunately this will determine my future ownership of a Yukon hybrid.
I'll provide more information when available.

 

You can probably find a used transmission for less than half of that. Or take a look at this store that sells new transmission parts. They have the electric motors available.

 

GMC reports the inverter and drive motor #2 are damaged and require replacement.
The inverter is also called the Drive Motor Generator Control Module.
They say there is one new transmission in the US.
Estimated $16k for everything on a truck worth about $6000.
Probably getting out of the hybrid business.
I'm located in central Florida and it has about 118k miles.
Greenbean replaced the battery under warranty couple weeks ago when this all started.
Anybody interested?

 

I suggest finding a used inverter/transmission from a wreaking yard it would be like 700$ or so..

 

My regular repair shop found a used transmission in Las Vegas with 128k miles which is more than mine.

For grins I looked for used hybrids in the south.
Check out this one.
https://carbuzz.com/cars-for-sale/gm...carId=13498918
I counted six errors in their list of features.
FWD ??
Adjustable pedals?
Full size spare?
Chrome wheels?
Fog lights?
Bluetooth?