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Discussion Starter #1
Yesterday I had my car valet parked. After 6 or so hrs I returned and was told the car would not start. I thought the parking attendant did not know how to use the car. I found the car completely dead. No horn, lights, nothing. The outside running lights on the front of the car were on, but very dim. I Googled this and saw that the 12V battery needed to be jumped. After doing this the car was fine except for the orange engine light. OnStar read me some error codes being thrown and after speaking to the dealer, I was told the car could reset itself - which it has not.
Error Codes:
The code(s) and explanation(s) associated with this issue is/are:

P0AC4 The electric propulsion system is not performing as expected. Please service within 7 days. There is another trouble code in the HCP, which may or may not be active at this time. If no there code is found, service within 7 days.

P1F64 The Engine and Transmission System is not performing as expected. An issue has been detected in the Hybrid Powertrain System that monitors and controls the use of power between the combustion engine and the electric drive system.

P25C9 The Engine and Transmission System is not performing as expected. An issue has been detected in the Fuel Management System used to maintain, control and monitor fuel consumption. If the check engine light is flashing, a misfire condition has been detected. A misfire increases vehicle emissions and could damage the emission control system on the vehicle. Please reduce vehicle speed, avoid hard accelerations, avoid steep uphill grades, and reduce any cargo loads such as a trailer.

Based on the results, you should service your Chevrolet within 7 days.

I've made an appointment to bring it in, but the dealer told me the codes could clear on their own by then.

How is the 12 volt battery charged? Does it come from daily charging or from the main battery? This took place after a 2hr drive using the engine for most of the trip. I had plenty of lithium battery left and gas.

The dealer feels it is fine to drive as long as the engine light is not flashing. It's just on. All recalls have been done.

I'm thinking the Valet left the car on - but would that cause this? What do you guys think? What could drain the 12V? :confused:
 

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Even if the valet left the car on, it will automatically shut off after 10 minutes of being in Park.

The car automatically charges the battery, when driving or plugged in, via an internal DC-DC "thing". I can't think of what it is exactly called at the moment. I've seen a few posts now about that piece failing and not charging the battery. The driver doesn't know that it isn't charging until the battery is finally dead.

Hope this helps a bit. Please let us know what the dealer finds or does. Good luck!
 

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I would not worry about all the error codes just yet. A bunch of codes will appear when the 12 volt battery does not perform properly. The 12 volt battery charges just like any other car while driving except the Volt does not have an alternator. It has an APM (Auxiliary Power Module) that does the same thing. There have been a few cases where the APM has died and therefore cannot supply the 12 volts necessary and the car tries to run off just the 12 volt battery until it is completely drained.
With a dead 12 volt battery, if the car started with the jump and ran ok, then the APM is good and the problem should be in the 12 volt battery itself. Maybe an internal short that causes it to drain itself quickly.
Leaving the car on while parked should not drain the 12 volt battery, but it will drain the HV battery. And, any lights left on while parked should turn themselves off after 10 minutes. My vote goes for a bad 12 volt battery.
 

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The 12V battery is charged through a DC/DC inverter that takes high voltage from the battery pack and drops it down to about 13V for the 12V system and battery. Leaving the car in service mode (very long press of the power button, 10+ seconds) would certainly drain the 12V battery in a matter of a few hours but I can't completely understand how or why they would do that. One other option might be that the valet accidentally turned the park lights on when exiting. This will use the 12V battery as well and might possibly drain the battery over 6 hours to a point that insufficient power was available for the ECUs to boot.

I can't speak on the gen 2, but I believe the gen 1 sends 13V to the 12V battery when charging the main battery, but ceases when the charge cycle is complete. The Gen 2 may also do that but I can't confirm.
 

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Even if the valet left the car on, it will automatically shut off after 10 minutes of being in Park.
If the car is left ON, it will turn off automatically after 2.5 hours. Only the lights and radio will turn off after 10 minutes but ONLY if the car is off.
 

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If the car is left ON, it will turn off automatically after 2.5 hours. Only the lights and radio will turn off after 10 minutes but ONLY if the car is off.
You are correct, sorry for that error. Per the manual:

If the vehicle is left in P (Park) while
running and the Remote Keyless
Entry (RKE) transmitter is outside
the vehicle, the vehicle will turn off
after one hour.
If the vehicle is left in P (Park) while
running and the RKE transmitter is
inside, the vehicle will run for two
hours. At the end of the second
hour, the vehicle will turn off
 

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Leaving the car in service mode (very long press of the power button, 10+ seconds) would certainly drain the 12V battery in a matter of a few hours but I can't completely understand how or why they would do that. One other option might be that the valet accidentally turned the park lights on when exiting. This will use the 12V battery as well and might possibly drain the battery over 6 hours to a point that insufficient power was available for the ECUs to boot.

I can't speak on the gen 2, but I believe the gen 1 sends 13V to the 12V battery when charging the main battery, but ceases when the charge cycle is complete. The Gen 2 may also do that but I can't confirm.
I had forgot about "Service Mode". It would be very easy for someone unfamiliar with the Volt (valet) to accidentally put the car into service mode by holding the power button too long. That would definitely run down the 12 volts.

The gen 1s from 2013 on and the Gen 2s will monitor the 12 volts while plugged in and not charging. If the 12 volts gets low it trickle charges to keep the 12 volt battery up.
 

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Either a premature failing 12V battery (easily checked) or the valet put the car into the Service Mode.
 

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The gen 1s from 2013 on and the Gen 2s will monitor the 12 volts while plugged in and not charging. If the 12 volts gets low it trickle charges to keep the 12 volt battery up.
FWIW: Measured on my Gen1 @13VDC being supplied to the positive battery terminal of the AGM when plugged in in actively charging either L1/L2...
 

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It could also be a loose connection at the 12V battery terminal posts or a loose or misaligned connector where the 12V battery connects to the rear fuse block.
 

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Is it possible that the car was turned off but the lights were turned on manually? Would the lights still turn off after X minutes/hours if turned on at the stalk?
 

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I'm sure a lot of others have stated these similar thoughts, but the 12V battery likely died due to some unexpected drain. Could be a module was frozen up, etc. It seems many new cars, with increasing software, experience these issues. To me it is very frustrating and there should be as much thought put into 12V battery rundown protection as they put into airbag systems, propulsion systems, etc. A frozen module should not be able to circumvent battery rundown protection. But we've seen these kinds of instances with the Gen 1 Volt as well and Bluetooth hanging up. Anyway, I digress.

Although, the fact you saw dim daytime running lights is telling. They should never be on when the car was off. It's possible the valet somehow engaged the service mode of the Volt, which will leave the Volt powered on from a 12V standpoint, but not power on the high voltage electronics or keep the 12V charged.

In any case, all the errors you're seeing are likely related to the 12V battery having died, all sorts of things rely on it for safety checks. After three on/off cycles (with actual driving), the codes should clear on their own. If they do not, then yes, bring it to the dealer. They can likely just clear the codes for you if you explain what happened, without charge, and then you can see if this crops up again.

Assuming all the "software hanging" type problems have been fixed in vehicles causing 12V battery drain, the next item GM should tackle is a more complex method for placing into Service Mode to prevent accidental engaging. I'd suggest ↑ ↑ ↓ ↓ ← → ← → B A :)
 

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Discussion Starter #13
Thanks ClarksonCote and all the others who have given me so much information. I too believe, that the daytime running lights were some kind of sign that something was left powered up - that's why I wanted to make sure I included this in my post. I'm hoping the codes will clear on their own and this will not happen again. I will keep you all informed.

Thanks again buds!!
 

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Thanks ClarksonCote and all the others who have given me so much information. I too believe, that the daytime running lights were some kind of sign that something was left powered up - that's why I wanted to make sure I included this in my post. I'm hoping the codes will clear on their own and this will not happen again. I will keep you all informed.

Thanks again buds!!
You originally said that the "outside running lights" were on but dim. That is different than the Daytime Running Lights. The DRLs are the white LED lights on the lower corners of the front. They ONLY turn on if the car is on and in Drive. They turn off when the selector is in Park. There is no way to turn on the DRLs with the car in Park. Maybe it was the Parking Lights that were on.
 

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Discussion Starter #15
The long thin lights at each corner of the front bumper are the lights that were on but dim.
 

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My vote is that the valet pressed the Power Button for too long a time, waiting for the sound of the engine:D:p
 

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I thought I had read that if the car is ON, the 12v battery is kept maintained or charged.

The 12v battery is monitored pretty well.
The 12v battery is charged when the car is plugged in AND THE HIGH VOLT BATTERY IS UNDER CHARGE. WHen the HV battery is charged, the charging system shuts down. At this point the car has to be started to charge the 12v battery from the HV battery.

This brings concern when the car is stored for a long time 3 weeks or longer because even if the car is plugged in, as long as the HV battery is fully charged, the 12v battery is not monitored until the electronics are started by turning the car on.

I'd like to know what he did that dropped the battery charge so low.
I think I'm gonna have to get one of those battery maintainers since the 12v battery seems to have a vulnerabilty as far as the Volt goes.


Stolen VOLT pursuit
https://www.youtube.com/watch?v=Fp2TGpE7gLs

Insurance Institute For Highway Safety Crash Test Results
http://www.iihs.org/iihs/ratings/vehicle/v/chevrolet/volt-4-door-hatchback/2017
 

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You originally said that the "outside running lights" were on but dim. That is different than the Daytime Running Lights. The DRLs are the white LED lights on the lower corners of the front. They ONLY turn on if the car is on and in Drive. They turn off when the selector is in Park. There is no way to turn on the DRLs with the car in Park. Maybe it was the Parking Lights that were on.
Still got some rain and lightning so I don't want to go outside and verify. However, I recall the DRLs stay on in PARK when the light sensor on the dash senses that it's dark outside. Anyone remember?
 

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If it's dark outside, at least dark enough to activate the main headlamps, those should remain on in park until automatic light control has been turned off or the vehicle is shut down. I can't speak for the gen 2, but gen 1 definitely turns the DRLs off when park is engaged during the day.
 

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Discussion Starter #20
If it's dark outside, at least dark enough to activate the main headlamps, those should remain on in park until automatic light control has been turned off or the vehicle is shut down. I can't speak for the gen 2, but gen 1 definitely turns the DRLs off when park is engaged during the day.
The car was in a DARK parking garage. That could have been it. The car has been fine. No problem yesterday morning. No problem after work. The engine light has gone off. No problem this morning. I'm chalking it up to user error at the garage and moving on. I may look into one of those mini jump starters to keep in the car just in case. Thanks for all the knowledge and information guys. I've learned a lot about how the 12v affects the workings of the Volt. Many thanks again! Ray
 
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