[FranandPat]

I find my 2014 (25k miles) now has no heat in EV mode as so many before me. Working through as many posts as I can to find some assurances and I'm afraid I'm not finding much. I have an appointment for this coming Tuesday to get it looked at so I'm using this time to get armed with knowledge before the dreaded hour.

The first real question is whether this is covered under warranty or not? This thread seems to say no or maybe: http://gm-volt.com/forum/showthread.php?271489-coolant-pump&highlight=heat Unsure if Customer Service resolved this one way or another.
And post #48 here: http://gm-volt.com/forum/showthread.php?209170-2014-Volt-Heater-Problem/page5&highlight=heat also has me guessing. My 2014 was purchased new in May of 2015. So, am I out of the B2B or am I good? There just seems no end to the possible answers.

Don't know which post I ran across a reference to PIC5943. https://static.nhtsa.gov/odi/tsbs/2013/SB-10063994-2273.pdf Seems to be the culprit but we also have 2015's with the same issue so is this an ongoing thing?

So, the never ending questions still leave me here... Is the K-10 Coolant Heater Control Module replacement the solution or something else? Has there been a resolution with the software update only? Is this covered under warranty or not? Is there an actual one size fits all solution or am I at the mercy of the service department?

 

[canehdian]

You're still under full warranty, so you're covered.
Let the dealer take care of it.

 

[TSquare]

The Bumper to Bumper warranty is for 3 years or 36K miles, so you are still covered. The dealer will probably just reprogram the heat module, check that it works, and send you on your way. If the heat fails again, then you take it back, and they will then replace the module.

 

[mpmoore1979]

Most likely the coolant pump. Have seen a few of these this year. Make sure the heat works before you leave the dealership when you are in EV mode and the engine has not been running.

 

[Belgin]

Unless you car was put in service in Oct 2014, you are out or warranty. Hopefully the pump is considered part of the Voltec system

 

[mpmoore1979]

If the was was sold new in MAY of 2015, your still under B2B warranty until MAY 2018 or 36k miles.

 

[FranandPat]

Thanks everyone. Hoping the warranty exists and no farting about replacing or guessing. I'm not averse to leaving it a day or two to get parts as long as they're actually the solution. Reading so many posts and then coming across this one with WOT's goodies makes me feel better: http://gm-volt.com/forum/showthread.php?270249-No-heat-in-2105-on-EV&highlight=heat+2015 and I will have copies of as much as I can get my hands on before I walk in. Can you tell I'd rather get a root canal than deal with car shops?

 

[Fred_B]

My 2013 had this issue and it was fixed with just a software update (under warranty).

 

[BeachVolt]

Issue just started on my 2014. Dealership checked and said it does not need a software update. No fault codes. I'm thinking it is the pump.

 

[El Dobro]

If the pump is working, you can hear it by listening in the right front wheel well.

 

[freshcut]

My '13 was just recently in for minimal heat in EV mode, and completely non functioning in gas mode. It turned out that the coolant control valve was "stuck" in the position that only allowed coolant to flow in EV operation, and apparently there is a filter somewhere in the system that became blocked. This all occurred after a 5 year coolant flush which I'm attributing the filter blockage being due to the flush loosening particles that plugged the filter. The coolant valve failure may have been in play for a while as I haven't used my heater in months until about 6 weeks ago when I discovered the issue, about a month after the coolant service.

You can check your warranty coverage on the my.chevrolet.com site. Only the B2B will cover the majority of heater issues. I was fortunate to have remaining GMPP coverage which paid for my repairs. If in fact it does require a software programming then the B2B should take care of that as well.

 

[FranandPat]

freshcut, I'd only paid a bit of attention to that site, but you're right. It actually has quite a bit of information. My warranty worries are now over (6 more months) so only the dread of dealing with the dealer.

 

[freshcut]

I wish you luck. Mine still isn't "right" but at least I do get some heat. Being in SoCal, heat isn't too much of an issue in winter, Of course colder areas during winter would yield much worse performance but at least I'm now getting warm air blowing out. I'll have to probe the actual temperature but I would guess it's probably blowing at about 90* now rather than feeling only bursts of cold and room temperature air when the a/c system cycles in the heat mode. Unfortunately my GMPP expired shortly after the repairs and I just don't feel like paying to have it looked at again since I have it working better than it was before.

 

[2VoltFamily]

I have 2 2013s. I had the K10 units replaced under B2B warranty. I had the software update recently which cost me.

 

[Bill Step]

If these issues happened w/ a Toyota,they'd be fixed and fixed so it never happened again.shame on gm w/ these failures.

 

[FranandPat]

OK...took the car in yesterday and waited a few hours for the diagnosis and whether they had the part. (Of course not!) Left overnight (opted to call the missus for a lift rather than drive the Silverado they were going to have me use) and just got it home this afternoon.

To recap, like many others I had heat in CS mode, it nearly immediately cut out when switched back to "normal mode". At rest the car drew 0.5kw and jumped to 6 for a moment when heat called for. Both heat and AC icons lit regardless of blower/vent position. Power draw quickly dropped to 0.5 again, icons lit and fan running...no heat and getting colder. Dealer diagnosed auxiliary pump #13597900 internal failure (pump motor running but impeller not turning). It was 24F this morning so would have been good time to test. But, this afternoon was about 50f and very sunny. The car was in the sun and very toasty when I picked it up. I tried the heat prior to leaving the dealer and it was weird at best. When heat was called for the HVAC power usage never went to 100%. In full fan and set to 80 the best I saw was 59%. There was warm(ish) air after a few moments so I figured I'd head home and see. On the way I used the ICE for a bit to check that side of things and there is sufficient heat from the engine loop. When I switched to normal mode the heat icon remained off until it hit a set point and then called for power from the battery for heat. I had good heat throughout unlike before where it died out immediately. Car is home, cooled down from the sun and running the ICE. I went out and started it. 0.5kw draw as expected. Call for heat and bumps to 6 or 7kw. HVAC shows 59%. Power slowly dropped to bounce between 2 and 3k. Air from floor vents is warm at best and both AC and heat icons are lit. It's as if the electric heat is only getting 50% of what it needs. Would it need programming to get over the confusion it seems to have? Is there yet another part that has failed or is failing?

 

[canehdian]

OK...took the car in yesterday and waited a few hours for the diagnosis and whether they had the part. (Of course not!) Left overnight (opted to call the missus for a lift rather than drive the Silverado they were going to have me use) and just got it home this afternoon.

To recap, like many others I had heat in CS mode, it nearly immediately cut out when switched back to "normal mode". At rest the car drew 0.5kw and jumped to 6 for a moment when heat called for. Both heat and AC icons lit regardless of blower/vent position. Power draw quickly dropped to 0.5 again, icons lit and fan running...no heat and getting colder. Dealer diagnosed auxiliary pump #13597900 internal failure (pump motor running but impeller not turning). It was 24F this morning so would have been good time to test. But, this afternoon was about 50f and very sunny. The car was in the sun and very toasty when I picked it up. I tried the heat prior to leaving the dealer and it was weird at best. When heat was called for the HVAC power usage never went to 100%. In full fan and set to 80 the best I saw was 59%. There was warm(ish) air after a few moments so I figured I'd head home and see. On the way I used the ICE for a bit to check that side of things and there is sufficient heat from the engine loop. When I switched to normal mode the heat icon remained off until it hit a set point and then called for power from the battery for heat. I had good heat throughout unlike before where it died out immediately. Car is home, cooled down from the sun and running the ICE. I went out and started it. 0.5kw draw as expected. Call for heat and bumps to 6 or 7kw. HVAC shows 59%. Power slowly dropped to bounce between 2 and 3k. Air from floor vents is warm at best and both AC and heat icons are lit. It's as if the electric heat is only getting 50% of what it needs. Would it need programming to get over the confusion it seems to have? Is there yet another part that has failed or is failing?

That sounds normal if it was mild temps outside.
The heater only draws as much as required to meet your setpoint. It won't go to max unless it's near or below freezing or your setpoint is max.
If you have another below freezing morning tomorrow, you should see max kW.

 

[FranandPat]

This is my third winter with this car and I've only seen the HVAC start at less than 100% when it had been run on ICE just prior. And lo and behold! This morning was 26F so I went out and checked again in case I was having a senior moment. And apparently I was! 6K draw and 100% HVAC. waited a bit and nice warm air. Another thing I never noticed (probably because I was driving) is the air icon and heat icon intermittently cycle on and off as needed. I was underwhelmed with the heat at my usual 74F setpoint and bumped it to 78F. Much warmer air, same power draw. All is good. I did find that the car was driven on electric about 0.13 miles and about 3 miles on gas after I left it (thanks Voltstats). I'm guessing the coolant loop was warm, the car was warm from the service bay and the car was sealed up in toasty sunshine. So yea, I was more than a little paranoid after reading all of the no heat stories here.

Thanks for indulging me.

 

[Steverino]

All is good.
I was more than a little paranoid after reading all of the no heat stories here.

Glad you have it figured out.

Regarding "all of the no heat stories", be careful of the amplification megaphone effect that a relative handful of issues posted here can have. A dozen threads on the topic can represent 1% of the cars on the road. Or less.

What you don't see is hundreds or thousand of threads from those having no issue, because those without an issue don't typically post "another day, no heat issues". I could easily fill up the forum every day with posts on all the things that are working great, as designed. But that's not what people usually post. If they did your "all of the no heat stories" would likely change to, "the relatively few no heat stories"

 

[freshcut]

Excellent point Steverino. People never complain when a product is working as designed. Overall I think many of us have much we could say that is positive and proves the reliability of all the Volts systems including heat. It's only when something doesn't work as we intend and always when we need it most that attention is given and specific issues are addressed.

It's like going to a restaurant, having a good experience, but never saying something because it's expected.....but when there is a problem, it's quickly brought to everyone's attention.