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Discussion starter · #21 ·
So far, the dealer has found nothing wrong with my Volt. Tomorrow will be the 15th day the dealership has had my car in their possession, and I've had it to drive only 9. There was a several hour window between me picking the car up from the dealer's service shop the first time and me learning more about how unique my situation was while reading this thread...which led to me calling a Volt adviser that I learned about on this very forum...which led to me returning the Volt to the dealer because nothing had been fixed and the underlying, potentially large safety issue was still out there looming. The service manager drove my car home last night and is doing the same tonight, hoping to replicate the accelerator pedal not doing anything when pushed and the car losing speed. He and his crew have put about 150 miles on the car since having it in the shop (I've only put 430 on it), but I'm wondering what happens if they can't get the car to duplicate the issue, as it (only (?)) happened to me twice in 400+ miles.

If they try and give me the car back without finding anything, what should I do? The car has done it to me twice in only a few days of owning it and I really don't think it is safe to drive a car that might not accelerate at the needed moment - especially on the frequently difficult and jammed roads and freeways of Southern California. Do I have any recourse and is there another level of service that I can take this to? I really like the car (when it is able to move forward) and I don't want to even think about getting rid of it, but I also need a car that I can feel safe driving my family around in.

Secondly, just to confirm what several people have said in this thread and others, when you have had the PPR light come on, does your Volt lose the ability to accelerate? Does it lose speed? Can it still maintain the speed of traffic? From what I've heard, my Volt should not be doing this when it has (flat roads/freeways), but I'm wondering if it losing speed and the ability to accelerate is normal when the PPR light comes on, or if a typical Volt behaves differently.

I'm trying to determine what needs to happen going forward and at the same time anticipate what the dealer might do - both for my benefit and for theirs. Thank you in advance for any and all answers...I really appreciate all of the time the community has spent trying to help me with my dilemma.

Brooks
 
Have you seen this......



2013 Chevrolet Volt Power Train Service Bulletin 341563

NHTSA: Action Number: 10047659 Service Bulletin Number: 341563
Report Date:
Oct 01, 2012Component:
Power Train
Summary: Chevrolet: due to software anomaly, hybrid powertrain control module (hpcm2)may open and reset propulsion power relays, and electric motor may temporarily stop, because of incorrect date information. Model 2013 volt. *pe
 
So far, the dealer has found nothing wrong with my Volt. Tomorrow will be the 15th day the dealership has had my car in their possession, and I've had it to drive only 9. There was a several hour window between me picking the car up from the dealer's service shop the first time and me learning more about how unique my situation was while reading this thread...which led to me calling a Volt adviser that I learned about on this very forum...which led to me returning the Volt to the dealer because nothing had been fixed and the underlying, potentially large safety issue was still out there looming. The service manager drove my car home last night and is doing the same tonight, hoping to replicate the accelerator pedal not doing anything when pushed and the car losing speed. He and his crew have put about 150 miles on the car since having it in the shop (I've only put 430 on it), but I'm wondering what happens if they can't get the car to duplicate the issue, as it (only (?)) happened to me twice in 400+ miles.

If they try and give me the car back without finding anything, what should I do? The car has done it to me twice in only a few days of owning it and I really don't think it is safe to drive a car that might not accelerate at the needed moment - especially on the frequently difficult and jammed roads and freeways of Southern California. Do I have any recourse and is there another level of service that I can take this to? I really like the car (when it is able to move forward) and I don't want to even think about getting rid of it, but I also need a car that I can feel safe driving my family around in.

Secondly, just to confirm what several people have said in this thread and others, when you have had the PPR light come on, does your Volt lose the ability to accelerate? Does it lose speed? Can it still maintain the speed of traffic? From what I've heard, my Volt should not be doing this when it has (flat roads/freeways), but I'm wondering if it losing speed and the ability to accelerate is normal when the PPR light comes on, or if a typical Volt behaves differently.

I'm trying to determine what needs to happen going forward and at the same time anticipate what the dealer might do - both for my benefit and for theirs. Thank you in advance for any and all answers...I really appreciate all of the time the community has spent trying to help me with my dilemma.

Brooks
I had an experience with "propulsion reduced" yesterday morning actually, however, my scenario was different than yours. I will say that when the car went into that mode I still had plenty of power and was able to keep up with traffic with no problem.

See my post here - http://gm-volt.com/forum/showthread.php?89266-Volt-ICE-engine-wont-run-Low-propulsion-warning-service-engine/page2
 
Question for the OP. How many times had this battery been fully discharged (to the point of extended range and engine run) and then recharged?
I suspect very little if any complete discharge-charge "cycles" have occurred which can have an impact on some of the algorithms used to calculate SOC and available peak power. That is the only time I have encountered such an anomaly and after completing 5-10 discharge-charge cycles there is never any reoccurrence of the indicated error.

Anytime the battery management system observes that the available peak power from the RESS is less than 35kW and the current demand may be exceeding that threshold the "Propulsion Power is Reduced" message will appear and the available power from the battery controlled in a fashion to prevent exceeding it's available headroom. (reduced power) This can occur normally under certain conditions most typically under high load such as climbing a steep grade, but can also occur if the battery cells are extremely cold (<5F/-15C). The message can also appear when certain DTCs have been triggered to control power levels as a fail-safe measure.

Under the condition the OP has described (and assuming no DTCs) there should never be such a message displayed.
So that leaves me to believe something may have gone wrong with the process of calculating the available power which is a function of the algorithmic estimations of SOC and active pack voltage and current measurements.
If there was something actually wrong with a particular piece of hardware that is involved in this process (eg. current sensor, voltage sensor/s etc) then the issue is sure to manifest at some point in a single discharge cycle and will be repeatable by the dealer technician. (and usually DTCs set)

But in short I have seen a few of these types of anomalies crop up on Volts that have sat on a dealer lot for an extended period of time, (usually with a dead 12V battery) then sold to a customer BUT then isn't initially charged and discharged to full depletion a few times in order to establish certain statistical base-lines in the software. If the car is driven for just short trips and then the charge simply "topped up" it can at times create some conditions that can cause this odd behavior. (as well as a few others like fuel used indications when the ICE hasn't run)
So barring some sort of actual battery cell/pack issue I suspect after a few complete discharge-charge cycles the issue will likely never be seen again.

HTH
WopOnTour
 
Discussion starter · #25 ·
Thanks again for all of the information. I'm not sure the status (# of full charge/discharge cycles, the current charge level or fuel level) of the Volt when it first refused to accelerate, but the second time it happened it was 1/2 way through its second tank of gas and had done several full cycles of charge/discharge. The car had gone through its electric range and was driving on gas alone (and had been for about 10 miles before the incident). Thanks again for the continued help, and I'll pass along information as I have it.

Brooks
 
Thanks again for all of the information. I'm not sure the status (# of full charge/discharge cycles, the current charge level or fuel level) of the Volt when it first refused to accelerate, but the second time it happened it was 1/2 way through its second tank of gas and had done several full cycles of charge/discharge. The car had gone through its electric range and was driving on gas alone (and had been for about 10 miles before the incident). Thanks again for the continued help, and I'll pass along information as I have it.

Brooks
Ahhh well that changes things a bit. From your initial description I had somehow assumed you were driving electrically, but you were in fact in extended range (CS) mode.
In CS an observed issue with ICE operation can also bring up this message. BUT typically there should have been DTCs as well. However depending on the fault it quite possibly might have been a Type-B DTC that only trips fully (and turning on the MIL/CEL) after 2 consecutive trips with failure. (sometimes called an "armed" DTC)
So a DTC may have been present as a "history DTC" and the dealership may have quickly discounted it.

The dealer tech can actually go back onto the PC originally used to check for DTCs in the car and retrieve the initial DTC scan results as GDS2 records that data for future reference. ( a handy feature not often used)

I suspect there actually was a DTC set, but without any driver indication such as the CEL. Knowing that DTC would help to establish what fault the ECM may have detected with the ICE.

WOT
 
I've owned my 2015 Volt for a little less than three weeks and have 400 miles on the odometer. I've been reading with interest about other peoples issues with the Propulsion Power Reduced warning, but I'm not sure what I've experienced is the same thing.

During the first few days of owning my Volt, I was driving down a flat road in town doing about 45 mph when the accelerator suddenly didn't respond. The car began to slow down despite me pressing down on the accelerator. There was thankfully a red light a block ahead and I more or less coasted to the light. While stopped, I frantically checked everything, thinking I had accidentally hit a button or switch. Nothing looked out of the ordinary, and I don't remember seeing the Propulsion Power Reduced light at the time. I also don't remember how much range I had left (if any) in electric mode. When the light turned green, I stepped on the gas and the car resumed its normal functionality and was fine. I assumed I had mistakenly pushed something I shouldn't have and quickly forgot the incident.

Several days later, I was driving the car on the freeway. I had about 30 miles of range on the charge and my destination was about 26 miles away, meaning that my return trip would be made mostly using gas. Fine - that is why I purchased this car instead of an all-electric. On my return trip, I made it most of the way home in stop and go traffic when the traffic started to lighten up. I stepped on the accelerator to maintain the speed of traffic and nothing happened. I floored it, and there was little to no response. I was losing speed in the fast lane and there was nothing I could do about it. I looked at the dash and saw a light that stated Propulsion Power Reduced (no kidding - I couldn't drive the car). The car was losing speed and didn't respond to anything my foot was doing on the accelerator pedal. I put the hazard lights on and came to a stop (again - this was in the fast lane of the 405 freeway in Los Angeles). I turned the car off while all around me cars honked and people flipped me off. When I turned the car back on after a moment or two, the warning was gone and the car reacted as it should. I had my wife call the dealership and I immediately drove there.

The service department rep told me that the Propulsion Power Reduced warning can come on when climbing steep hills. I told him that I was on flat roads both times the car failed to accelerate and he seemed surprised by this. It was late on a Thursday, and I was leaving for a week long trip the following evening. The serviceman told me he'd try to get it to me before I left the following day, but was not able to. I didn't hear back until this past Friday (the car had been in the shop just over a week), and the message I got was that there was nothing wrong with my car and to come pick it up. I am now back in town and just got off the phone with the service department. They assured me that while my car twice refused to accelerate on flat roads (one a residential street, one a busy freeway) that nothing was wrong with it. I've only had the car in my possession for eight days (it has been in the shop for longer) and what has happened isn't safe. If I'd had any idea this was a possibility, I never would have purchased this car.

I would be very interested to hear if anyone else has experienced anything like this and if so what the outcome was. I've been told that the car has performed as it should, yet I've never owned a car that didn't go forward when you stepped on the gas. Again, the car is a brand new 2015 Volt with only 400 miles driven in 8 days of being at my house. I'm concerned and want to know if this is a problem specific to only my car, or if this is something that has happened to others, and if so, was there a solution. Thank you in advance for any help or assistance.

Brooks

I have gone through an experience just like you.That is very terrifying.





sony e1 hĂĽlle
 
With all the computer systems one would think this incident would have triggered a Code somewhere in the system. I would
not have my wife drive any car, espicially a 2015 model year vehicle, with this problem not fixed. I would start contacting supervisors of supervisors to the top of GM's head person. This is unacceptable.
 
I know this belongs in suggestions, but the present issue makes the case.

There are holster monitors you can wear for your heart, your blood sugar, your sleep respiration, even your brain waves.

Solid state storage with amazing capacity is now really inexpensive.

GM should come up with a piece of test equipment that sits on the CAN port and records everything until a problem recurs and the driver or dealer stops the recording. The data would be transmitted back to the factory offline. I expect the GM already has analysis software for the CAN data stream.

In the end, DTC codes are programmed actions because some engineer thought something might happen. No one can think of everything.
 
With all the computer systems one would think this incident would have triggered a Code somewhere in the system. I would
not have my wife drive any car, espicially a 2015 model year vehicle, with this problem not fixed. I would start contacting supervisors of supervisors to the top of GM's head person. This is unacceptable.
Reading WOT's reply above http://gm-volt.com/forum/showthread.../showthread.php?166562-2015-Volt-Propulsion-Power-Reduced&p=2351250#post2351250 he seems to think it likely did trigger a code and the tech needs to go back and review the log looking for DTC's that may have been dismissed and compare with the log for the second event.
 
Discussion starter · #31 ·
Day 19 that the car has been in the shop (I've only had the car to drive for 8 or 9 days) and I heard yesterday that an engineer from GM was coming down to my dealership to look at the car. He was supposed to arrive yesterday or today but unfortunately didn't. As I started typing this update, I received a call from the dealership to say that the engineer from GM ran into a problem and wouldn't be able to examine the car until Thursday, which will be day 21 that the car is in the shop. I'll write more when I've heard something worth updating. Thanks again for the continued support.

Brooks
 
Discussion starter · #32 ·
Obiwan - I saw your post that stated that you have encountered a similar situation with your Volt. Did it happen only once, and under what conditions? Was the dealer able to find the issue and if so, what was it? Very scary. I'm sorry you also had to go through this and I'm hoping Chevrolet was able to fix your Volt so that it the problem hasn't recurred. All the best, and thank you for your post.

Brooks
 
Discussion starter · #33 ·
I just heard back from the dealer. The GM technician looked at my Volt yesterday and the service person I talked to told me that they were ordering a new transmission control module to put into the car. The part should arrive on Monday and I should get the car back on either Monday or Tuesday. I'm not mechanically inclined (an understatement), but am wondering if that malfunctioning part could be what caused my Volt to twice (under difference circumstances) stop accelerating and in at least one of the cases, trip the Propulsion Power Reduced light on the dash. I'm a bit wary of my dealership's service department after they sent me on my way the first time saying there was nothing wrong with the car, and I want to make sure this will (hopefully) make my car safe to drive, and not simply be a way of them getting me out of their hair. Thank you in advance for any insight or advice.

Brooks
 
Thank you for all of the great posts. I will try and answer the questions from the forum as best as I can.

*I didn't think to push the Onstar button as the car is brand new and I didn't remember it was there. I also wasn't thinking of that when it wouldn't move forward in the fast lane. I'll keep it in mind the next time it happens (finger's crossed it doesn't)

*The car was not out of gas. It had at least a half tank.

*The check engine light did not come on - only the PPR (I don't recall if the PPR came on the first time the car failed to accelerate).

*I did not drive up a hill prior to the failure of the car to accelerate normally. After I restarted the car on the freeway, I drove it on the flat for another five miles before going over the mile or two "pass" between the San Fernando Valley and the Santa Clarita Valley with no issues, other than my rattled nerves.

I just picked up the car from the service department of the Chevy dealer I purchased it from and was told the car had a clean bill of health and that there was "nothing wrong with the car". The technician who looked at my car was at lunch and I am expecting a call from him for more information, but they told me expressly that they found nothing.

Along those lines, I am new to this forum as of today, and I don't know anything about the Volt Advisors. I apologize in advance for my ignorance, but any help is certainly appreciated. Thanks again for the assistance, and I will certainly share more when I know more. I just wanted to make sure that this wasn't a common issue before I decided to push the dealer's service department a little harder.
Brooks,

You came to the right place. The depth of domain knowledge here is staggering. Everyone is here to help and we will all need to share in someone's experience at some point.
 
Discussion starter · #35 ·
After 29 days in the service department, I received a call on Friday to tell me my new Volt was ready to pick up and safe to drive. They replaced the transmission control module and said that the car was as good as new. After three days of driving it, the problem has yet to resurface - fingers crossed that it stays that way. I just wanted to say thank you to everyone that contributed here to help me figure out the cause and tell me the appropriate steps to take to get the car fixed despite the dealer telling me everything was fine. I can't tell you how comforting all of the posts were. Thank you, and all the best.

Brooks
 
As Brooks hasn't been on the board in a few months a can only assume the problem is solved. Sure glad GM and the service department got to the bottom of the issue.
 
Brooks, I bought my car last night at Chevy of Irvine and the same thing happened as I was driving back to Los Angeles on the 5 freeway. Do you think your car is fixed now? Which dealer service did you work with? Thank you
 
I had this happen to my 2016 chevy volt at just below 4000 miles. It would not start back up and got towed to Putnam in Burlingame california. They replaced the entire transmission. Not sure if problem will return, but I have driven it a few hundred miles since without it recurring. I suggest calling GM directly. You should not have to take back an unsafe vehicle that they have not attempted to fix.
 
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