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We purchased our 2011 Volt vin # ...0236 new and took delivery in December 2010. We have thoroughly enjoyed our Volt but we are experiencing something that we do not believe should occur. As mentioned, we have owned our Volt for 6 ½ years and feel that we understand how the vehicle should perform. The vehicle currently has 69k miles of which 58k are E miles. We have started receiving the following message "Propulsion Power is Reduced" after the electrical miles have been exhausted. Which has generated an acceleration problem under normal economical driving conditions. The acceleration is significantly reduced. We have documented this with dated and mileage photographs. We first noticed this message in 2015. We contacted OnStar and they recommended that we take the vehicle to our local dealership. The dealership could not reproduce the message at that time. It occurred (4) times in 2016 and it went back to the dealership. The vehicle has been to the dealership several times over the last year. We have documented this message (9) times so far this year. The problem has been reproduce and documented by the dealership. They recently sighted a technical bulletin. Which states that this could occur if the vehicle is traveling at steep inclines or if the vehicle is driven aggressively. We tried contacting our Volt adviser and learned that the department has been dismantled. We contacted GM customer service regarding problem and they recommended that we take the vehicle to another dealership for a 2nd opinion. The recommended 2nd dealership reproduced the problem as well. GM customer representative followed up stating that the case was being closed with no resolution. The representative sighted that GM knows that the issue occurs yet it's normal. How can they believe it is normal to have no acceleration? This is a very uncomfortable feeling entering a highway with no acceleration. We have sat upwards of 10 minutes waiting for the vehicle to allow normal acceleration. Has anyone else experienced this?
 

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That's interesting. Does PPR (Propulsion Power Reduced) show up every time when the Volt goes into REx mode? Has it generated any codes? OnStar can tell you if there are any codes. Most auto part stores also have free code reading. Normally the Volt will only go into PPR if the battery is critically low, it's low on fuel (Even with full battery), or there's something wrong with the drive train (Which should have a code associated).
 

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I'm guessing there is an intermittent faulty sensor or wire somewhere. For example if the car is low on coolant, the ice might fire every other cylinder to avoid overheating.
 

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Of course it's not normal. The only time this would be normal is if you first exhausted the battery and then put the car under a lot of stress, such as steep hills or on a track. Are you sure this is what they've said or is there something you're not mentioning? If the dealer reproduced the problem what did it say was the root cause?
 

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When the Gen 1's battery reaches the fully depleted level, the ICE starts up, and the generator output is supposed to be enough to maintain performance except under high demand circumstances (such as passing while driving at freeway speeds up steep mountain roads). If too much power is needed and the battery state of charge is at the minimum so the motor can't borrow some extra power from the battery, the car will go into Propulsion Reduced mode until the demand lessens. That’s why Gen 1 drivers are supposed to use Mountain Mode (or Hold) to reserve a buffer of battery power when driving up mountains.

What you are experiencing is not normal. There might, of course, be something that’s started to go wrong with your car, but one would expect to see error codes (unless this happens only while the a/c is cranked up high because of the heat, draining the power?)...

It could be 1) for some reason your 2011 Volt doesn’t transition to ICE until the battery state of charge is actually lower than the normal "fully depleted" level, and thus when extra power is demanded (such as when you try to speed up to merge onto a freeway), there is even less available in the battery and you get the Propulsion Reduced message... see if you can get a fully depleted raw battery state of charge reading from the OBD2 port (my 2012 Volt usually reads 20%-22% at the fully depleted level).

Or 2), the generator output is providing less power than it should, so the demand to borrow some from the battery comes even sooner, and with no spare power to borrow, you get the Propulsion Reduced message...

If the Propulsion Reduced message is happening more frequently, you could try driving in Mountain Mode to see if that eliminates the problem. In a 2011 Volt, when you switch to MM, the estimated ev range immediately drops by ~14 miles (the MM-maintained buffer). MM maintains a "buffer" of extra battery power in case its needed to maintain performance under high demand conditions (e.g., driving up steep mountain roads). This buffer should be enough to maintain performance as you perform your normal daily driving, merge onto freeways, etc. If you run into the Propulsion Reduced problem even when using Mountain Mode, then something is wrong.

You could also try this: the Self Charging Chevy Volt youtube video shows a 2012 Volt using MM to charge a fully depleted battery to the MM-maintained level in 15 minutes using 0.36 gallons of gas while parked. It should also take the same 15 minutes for a 2011 Volt if the generator output is performing as it should (i.e., if it takes much longer than 15 minutes, something might be wrong with the generator’s output). If you try it while parked with a fully depleted battery, the ICE will start when you switch into MM, and will turn off by itself when the MM-maintained buffer has been filled, so you can time it, and you can see how much gas was used. Turning the car off and back on at that point should restore the battery icon on the display to show you the ev range estimate from the MM recharging.
 

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Of course it's not normal. The only time this would be normal is if you first exhausted the battery and then put the car under a lot of stress, such as steep hills or on a track. Are you sure this is what they've said or is there something you're not mentioning? If the dealer reproduced the problem what did it say was the root cause?
So back to the OP, when you got these 9 instances of reduced propulsion, you wouldn't happen to be driving in mountains using Normal mode, would you?
 

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I assume the batteries TMS system and coolant (level/sensor) have been given a once over and eliminated from the list of possible causes?
 

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It could be 1) for some reason your 2011 Volt doesn’t transition to ICE until the battery state of charge is actually lower than the normal "fully depleted" level, and thus when extra power is demanded (such as when you try to speed up to merge onto a freeway), there is even less available in the battery and you get the Propulsion Reduced message... see if you can get a fully depleted raw battery state of charge reading from the OBD2 port (my 2012 Volt usually reads 20%-22% at the fully depleted level).
The battery state can easily be checked if you have an obd2 dongle (cheap from amazon, $15-20) and a smartphone with the mygreenvolt app. This may provide some very useful data since it will also let you see how much power your receiving from the generator when in REx as well.
 
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We purchased our 2011 Volt vin # ...0236 new and took delivery in December 2010. We have thoroughly enjoyed our Volt but we are experiencing something that we do not believe should occur. As mentioned, we have owned our Volt for 6 ½ years and feel that we understand how the vehicle should perform. The vehicle currently has 69k miles of which 58k are E miles. We have started receiving the following message "Propulsion Power is Reduced" after the electrical miles have been exhausted. Which has generated an acceleration problem under normal economical driving conditions. The acceleration is significantly reduced. We have documented this with dated and mileage photographs. We first noticed this message in 2015. We contacted OnStar and they recommended that we take the vehicle to our local dealership. The dealership could not reproduce the message at that time. It occurred (4) times in 2016 and it went back to the dealership. The vehicle has been to the dealership several times over the last year. We have documented this message (9) times so far this year. The problem has been reproduce and documented by the dealership. They recently sighted a technical bulletin. Which states that this could occur if the vehicle is traveling at steep inclines or if the vehicle is driven aggressively. We tried contacting our Volt adviser and learned that the department has been dismantled. We contacted GM customer service regarding problem and they recommended that we take the vehicle to another dealership for a 2nd opinion. The recommended 2nd dealership reproduced the problem as well. GM customer representative followed up stating that the case was being closed with no resolution. The representative sighted that GM knows that the issue occurs yet it's normal. How can they believe it is normal to have no acceleration? This is a very uncomfortable feeling entering a highway with no acceleration. We have sat upwards of 10 minutes waiting for the vehicle to allow normal acceleration. Has anyone else experienced this?
Hi nsours,

If you could email [email protected]? We'd like to take a look at this situation further on our end, and help as best as we can. Please be sure to use "ATTN: Amber" as the subject type, and include your VIN within your email.

To review the GM privacy policy, please visit https://www.gm.com/privacy-statement.html.

Kindly,

Amber G.
Chevrolet Customer Care
 

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I would assume there are no code set in any computer for the hybrid system since there are no repairs made. It seems to me there is no hard part failure but there may be a software issue. If the car was in my shop, I would start off with updating all hybrid computers to the latest software. Then I would perform a Hybrid/EV Battery Pack Capacity Learn to see if this helps. The Hybrid Powertrain Control Module 2 has a learned value for the battery and if its off, then it may be letting the battery to discharge below spec and give you this issue. I would as the dealership to perform this relearn to see if this helps.

Hybrid/EV Battery Pack Capacity Learn

The Hybrid Powertrain Control Module 2 learns the battery capacity as the Hybrid/EV battery pack is discharged and charged. Once learned, the capacity value is allowed to change over a long period of time, as the battery ages.

Replacement of the battery pack, all battery sections or the Hybrid Powertrain Control Module 2 requires capacity learning at a faster rate than normal.

To enable hardware replacement, the Hybrid Powertrain Control Module 2 can be placed into a fast learn mode with the scan tool.

Activating the fast Capacity Learn mode will reset the battery capacity to a much lower value and subsequent charge/discharge cycles will then learn the capacity back up to the proper value. Initially this may have a noticeable effect on EV range until the capacity learning for the new hardware begins. It may take several battery pack depletions and charges for a maximum EV range to be learned/displayed.
 

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The check engine malfunction light has not illuminated. I contacted Onstar and they Performed a diagnostic and found no codes. They recommended that we take the car to our local dealership. As previously stated, they could reproduce the same issue. We never drive in any other mode than "normal". They just recently cited a technical bulletin regarding this. The bulletin stated that the warning could occur if the vehicle is driven aggressively or at steep inclines. The message displays after the car has run out of electric miles and then restarted. We contacted customer service after the dealership cited the technical bulletin. Customer service recommended that we take it to a second dealership for a second opinion. Again they came up with the same bulletin that the first dealership presented to us. Until the car displays the malfunction light and produces codes it seems like we're out of luck. I'm not technically savvy and not comfortable taking the vehicle to a non-GM repair center. What I do know is that we never had this problem and now we are. I just want the car to perform as purchased. Again, after 6 1/2 years we still love our car. Just getting discouraged.
 
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