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Discussion Starter #1
I have a MY2014 Volt, purchased new in March 2015, making the car about 15 months old.


Sunday 7/3: The dash indicator came on and showed error messages: "Engine Not Available, Service Soon" and "Propulsion Power Reduced". CEL is also illuminated. A picture of the message is attached.

The acceleration is very sluggish for the rest of a 3-mile drive. On the return trip home, the same indicator messages show and performance is again very sluggish.

I called OnStar, who provided codes P0700 and P2715. OnStar recommended servicing within one day if possible.


Tuesday 7/5: I drove the car 10 miles to dealership. All electric miles. No error messages this time, car performance is normal. CEL is still illuminated.

Service Dept says there is an outstanding recall 14522 and will execute this rework as well. They sent me home with a loaner Cruze.

Service called later in the day and said they are ordering a replacement Transmission Control Module (TCM). Will take two days to get part. Access to the TCM is restricted within the car, so they want to have the part on hand before they dig in. They confirmed that this is a warranty repair.


Thursday 7/7: Service called to confirm that TCM arrived. Planned to install today. Service did not call later in the day.


Friday 7/8: I called the dealership in the morning. They said that the assigned tech was too busy servicing priority Corvettes. Would try to complete the repair today.

Service called back after lunch and said that a Seal Kit had to be ordered. Would not be in until Monday, 7/11.



This sounds similar to the issues described in this thread:
http://gm-volt.com/forum/showthread.php?102305-Transmission-Control-Module-(a.k.a-valve-body)-Replacement


Anyway, I'm trying to be patient. I have a loaner car while the Volt is in the shop.
 

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I find it odd that the fuel gauge reads almost half a tank and the LOW indicator is displayed along with total range reading LOW.
With the "engine not available" the total range is now 36 miles. That would qualify as LOW for what is now a BEV Volt.
 

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To give you some peace of mind, I had no further trouble with the TCM replacement in the subsequent year of driving until I turned in the leased car on March 3rd, 2015. Welcome to the rather exclusive club. lol:cool:
 

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This is a rare occurrence, however unfortunate.
P0700 is more of a "generic" code indicating the transmission control module is requesting the check engine lamp (MIL) It's the TCMs equivalent of the P1E00 we see in tandem with almost any hybrid propulsion DTC.

The P2715 (as I'm sure the dealer has explained) is indicating one of the electrically controlled solenoids that control shift valve movement is indicating the valve is "stuck ON". Commanded shift valve movement uses observed pressure changes as feedback to it's physical movement and in this case there's indication either the solenoid is staying OFF mechanically/electrically even when requested ON, OR the shift valve itself is stuck/staying in it's ON position.

The service procedure uses a few manual control tests using the scan tool and GDS2 and once the condition is confirmed the TCM/valve body (they are integral) would very likely need to be replaced. (sometimes techs will be able to free-up a stuck valve but all too often the issue returns)

It's a fairly easy job as it's all pretty accessible without too much disassembly. (The black pan at the front of the drive unit must be removed and the TCM unbolted from the unit)

Hopefully you are back in your Volt very soon

WopOnTour

 

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Discussion Starter #6
Guys, thanks for the comments. The dealer didn't communicate what was going on very clearly, so this extra context was very helpful.

They ended up being able to get the new TCM and seals installed without any issues (on Monday, July 11). All the diagnostics checked out fine. They went ahead and replaced the evap canister per recall 14522 and gave the car a wash and a full charge.

All together, it took about a week to get the car fixed. Everything seems to run fine now. It's great to be back in my Volt!
 
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