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Discussion Starter · #1 ·
Has anyone had this problem

2011 volt #249, 110k miles

Initializing for a long time, then R or D just allowed the car to rolll. No motor engagement.

Vehicle Car Multimedia


Dublin Chevy had not seen this problem before. They called GM and were told how to reset relay center. GM recs replacing this relay center.

Anyone heard of this? Are there independent garages that can work on volts now? Is the cost of Volt maintenance expensive after the warranty has ended?

These are the DTC codes

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A relay? Or a "relay center"? Have heard of the latter before.
 

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I have had 1 issue like this before. You have a loss of isolation om the high voltage system. GM had me replace the high voltage contactors (high voltage relays located in the battery pack) and this did not fix the issue. After a few more calls, they told me to remove the fuse for the coolant heater to see if this fixes the problem. I did that and it did fix the problem, the coolant heater was shorted. This is a easy check for a Volt tech, you can not do this at home in a safely, its in the high voltage system.
 

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Discussion Starter · #5 · (Edited)
Stevereno - they said relay center

Mpmoore - that's good info. Is there a service bulletin to refer them too? Should I have them try the coolant heater fuse first? Apparently this is a $2,000 job for the relay center.
 

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Please, please. please tell us this is a CARB car... Because then your Voltec warranty is good for 150k miles instead of 100k. (If you're not sure, mychevrolet.com can tell from the VIN.
 

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Discussion Starter · #7 ·
Please, please. please tell us this is a CARB car... Because then your Voltec warranty is good for 150k miles instead of 100k. (If you're not sure, mychevrolet.com can tell from the VIN.

I don't think so. This was car number 249. 2011 did not meet the California standards. I think my warranty ended at 100k miles ��
 

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There was no bulletin for the issue I had, it was a problem with the contactors slow to engage which turns out after many calls to GM it was a loss of isolation issue which caused the contactors not to close and there were no loss of isolation codes set. The case was sent up the engineer chain and that's what they told me to try. They had just only a few cases of the coolant heater shorting out and every car it caused a different code to set in each car. I would try the fuse first, there is a 30 amp fuse for the cabin heater module. This fuse is located at the power inverter module. Or they can unplug the high voltage connection at the cabin heater module. This should isolate the heater from the high voltage system. If the car powers up, then the heater is shorted. Even if the heater is shorted, it will not blow the fuse, the loss of isolation in the high voltage system will cause the contactors to open first.
 

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Discussion Starter · #9 ·
There was no bulletin for the issue I had, it was a problem with the contactors slow to engage which turns out after many calls to GM it was a loss of isolation issue which caused the contactors not to close and there were no loss of isolation codes set. The case was sent up the engineer chain and that's what they told me to try. They had just only a few cases of the coolant heater shorting out and every car it caused a different code to set in each car. I would try the fuse first, there is a 30 amp fuse for the cabin heater module. This fuse is located at the power inverter module. Or they can unplug the high voltage connection at the cabin heater module. This should isolate the heater from the high voltage system. If the car powers up, then the heater is shorted. Even if the heater is shorted, it will not blow the fuse, the loss of isolation in the high voltage system will cause the contactors to open first.
I presume that this fuse is deep inside the car, not something that I can get to?

Do you think the car will randomly not start in the future? No chance of contactors opening while driving?

thanks for this info.
 

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The fuse that needs to be removed can not be done without disabling the high voltage system. Not sure what the future will bring.
 
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