P0C17 and P0C18 Tahoe Hybrid 2008

  #1  
Old 02-10-2019, 08:59 PM
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Default P0C17 and P0C18 Tahoe Hybrid 2008

Hello. I have Tahoe Hybrid 2008 car not started.We install new 12v battery but car still not started.
I have 2 trouble code:
P0C17 Drive motor A position sensor not learned
P0C18 Drive motor B position sensor not learned
Any body help me please.
Thanks
 
  #2  
Old 02-10-2019, 10:27 PM
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Default Re: P0C17 and P0C18 Tahoe Hybrid 2008

Check the voltage of the hybrid high voltage battery through a scan tool (or if you know what you are doing and observe high voltage safety precautions, check at the high voltage battery terminals). If the voltage is less than 192V, the computer will not be able to learn the drive motor positions. This could also be why your Tahoe is not starting. Dead hybrid battery. If your battery is too low, you may not need a new one. You just need to find a hybrid tech who can "grid charge" the whole pack at once.
 

Last edited by Jaime; 02-11-2019 at 07:28 PM.
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Old 02-11-2019, 06:38 PM
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Default Re: P0C17 and P0C18 Tahoe Hybrid 2008

So big C what is the background on the vehicle? Has it been setting un-driven for a long period of time?
 
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Old 02-12-2019, 06:13 PM
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Default Re: P0C17 and P0C18 Tahoe Hybrid 2008

Originally Posted by Jaime View Post
Check the voltage of the hybrid high voltage battery through a scan tool (or if you know what you are doing and observe high voltage safety precautions, check at the high voltage battery terminals). If the voltage is less than 192V, the computer will not be able to learn the drive motor positions. This could also be why your Tahoe is not starting. Dead hybrid battery. If your battery is too low, you may not need a new one. You just need to find a hybrid tech who can "grid charge" the whole pack at once.
I found an official document GM where it is indicated how to charge the battery.Jump assist mode.
but for that I need GM tech 2 scanner tool.
 
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Old 02-12-2019, 07:15 PM
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Default Re: P0C17 and P0C18 Tahoe Hybrid 2008

Originally Posted by Chicago38 View Post
I found an official document GM where it is indicated how to charge the battery.Jump assist mode.
but for that I need GM tech 2 scanner tool.
I recently purchased one of
these VCXNano scantools these VCXNano scantools
that comes with a Windows version of a Tech2. This may let you initiate the Jump Assist mode. I would first verify that the battery really is discharged by reading the module voltages. If you already have an OBD2 scanner, look at the following post that shows you how to read the voltages:

https://www.greenhybrid.com/forums/f...results-31736/
 
  #6  
Old 02-15-2019, 03:52 AM
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Default Re: P0C17 and P0C18 Tahoe Hybrid 2008

Originally Posted by Jaime View Post
I recently purchased one of these VCXNano scantools that comes with a Windows version of a Tech2. This may let you initiate the Jump Assist mode. I would first verify that the battery really is discharged by reading the module voltages. If you already have an OBD2 scanner, look at the following post that shows you how to read the voltages:

https://www.greenhybrid.com/forums/f...results-31736/
we tow the car to Chevy dealer. they made a diagnosis and said that the replacement of the Drive motors is required. but it is easier to change the whole transmission with a $ 6000
they tried to clear trouble code and reprogram the sensor, but it didn't work out. They tried 12 times. The last thing they can do is change the whole transmission.
 

Last edited by Chicago38; 02-15-2019 at 03:58 AM.
  #7  
Old 02-15-2019, 04:40 AM
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Default Re: P0C17 and P0C18 Tahoe Hybrid 2008

That is an expensive transmission. $6,000.00 might not be much money to you but ole dnt1010 says woah hold up here a minute LOL. If this were mine I would want to get another opinion, even if I had to have it towed to a hybrid specialty shop. When I see these dealership diagnosis I am always reminded of the time I had bought a new ford truck and the cruise control stopped working. Took it in and they said it was a bad control module and they would have to order it and would be weeks before it came in. When i got home I crawled underneath the truck just to look it over a bit and found that my New Puppy Dog had chewed the wiring harness. Wired it back up with some wiring connectors and shrink tape and drove it for years no problems. Moral of the story is sometimes these guys just simply overlook what should be be obvious.
 
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Old 02-15-2019, 05:34 AM
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Default Re: P0C17 and P0C18 Tahoe Hybrid 2008

Originally Posted by dnt1010 View Post
That is an expensive transmission. $6,000.00 might not be much money to you but ole dnt1010 says woah hold up here a minute LOL. If this were mine I would want to get another opinion, even if I had to have it towed to a hybrid specialty shop. When I see these dealership diagnosis I am always reminded of the time I had bought a new ford truck and the cruise control stopped working. Took it in and they said it was a bad control module and they would have to order it and would be weeks before it came in. When i got home I crawled underneath the truck just to look it over a bit and found that my New Puppy Dog had chewed the wiring harness. Wired it back up with some wiring connectors and shrink tape and drove it for years no problems. Moral of the story is sometimes these guys just simply overlook what should be be obvious.
I absolutely agree with you. 6,000 for this repair is not acceptable. It's easier for me to sell it for parts. But I'm not going to give up. I just took him back home and now in search of a solution.
Sorry for my english this is not my born language:-)
 
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Old 02-18-2019, 04:59 PM
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Default Re: P0C17 and P0C18 Tahoe Hybrid 2008

Do you think my problem may be related to poor contact or cable harness in the transmission?
 
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Old 02-18-2019, 05:09 PM
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Default Re: P0C17 and P0C18 Tahoe Hybrid 2008

Originally Posted by Chicago38 View Post
Do you think my problem may be related to poor contact or cable harness in the transmission?
Might be worth reseating all of the connectors. Strange to me that both position sensors would fail at the same time. If you can find pinouts for the connectors on the trans that might be a start for troubleshooting...make sure proper voltage is at the pins necessary. If they are sensor pins going back to the PCM or TCM, Id assume they are fed by a 12V line.
 

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