2016 Chevy Volt codes

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Ned Ludd's bro
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I guess once again we’ve been given us the fickle finger of fate.

We have 92,000mi on it and it has been a great car. No real probs and SO decided to pay off the last of what was owed. Then last nite says the check the engine lite was on steady and it was still running on electric, WTH? So I went out and popped the hood and checked all the fluid levels etc and everything looked good. No leaks underneath. Started the engine and let it run and it sounded ok, ran through the info thinking I might have forgot the reset I last time I changed oil and it said 83%. Thought I’d drive it and shut it off, closed the hood, and the lite was off, ??? Drove it around and no lite. This morning drove to the beach about 20mi and no lite. But on the way back noticed it’s back on. We drove it enough to run out of ev’s and the engine came on normal but still lite on steady.

Hooked up ODB reader and got p2517 and p1000. Looked on the net and it sounds like either low AC, or sensor and either the fuel pump control module and/or harness problem. I know there are some other Volt owners on here and maybe some tech’s, any thoughts?
 
no idea about Volts, but the first thing I always do is clean the gas cap (if it has one) and give it a light coating of vaseline or silicon grease. CELs are ALL about emissions, so only things that will affect emissions will throw a light.

Looked up those codes and the p2517 seems to be the one of interest (the other is just a "light the light" code) and it's about the AC low pressure sensor. Not sure how that would affect emissions, but either way, find the sensor, most likely on the bigger pipe coming back from the cabin to the compressor. Disconnect it, spray the plug liberally with electronics cleaner and reconnect. If that doesn't work, you may need to buy a new sensor. There aren't any on Rockauto, which suggests it's not a common failure, so hopefully a clean and reseat will work.
 
One thing to think of on an EV or Hybrid is that the AC system is also used to cool the high-voltage battery and some other components in the high-voltage system so it could set A/C codes in the PCM. P1000 pretty much means that codes have been cleared and the monitors have not completed verifying all systems are ok. P2517 could indicate low refrigerant or an electrical issue with the refrigerant pressure sensor. might not hurt to see if you can see any wiring issues or critters chewing under the hood. Now take this all with a grain of salt because I am a tech in one of the shops with a blue oval not the bowtie. :cool:
 
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P1000 just means that the readiness monitors have not all been successfully run. The air conditioner monitor is an option in those, and sometimes, but not always, is tied to the OBDII emissions system. Dollars to donuts, because the failsafe programming would have to stop using a hot HV battery and rely fully on the engine, the A/C monitor is mandatory/engine emissions related on that vehicle. So the check engine light comes on.

P2517 means that the powertrain control module detects short to ground or open circuit on the low side A/C pressure sensor circuit. (Circuit design, either fault yields the same observation when viewed from inside the PCM housing).

So, sensor, broken wire, or a wire rubbed through on something else, are likely causes, with the PCM being possible, but pretty unlikely with no other issues or concerns. Possibly the state of charge of the A/C system, however it "shouldn't" go out of range over a valid zero reading without flagging a P0532? first. Either a "low refrigerant", or a "signal performance" code. You have a circuit code.

If you speak electricity, you could probably sort that out easy enough, as by far the most likely cause is a failed three wire transducer. Vref at 5 volts, Low ref at sensor ground (not engine ground), and a signal return. If that's for you, there it is, and worst case you're out some annoyance for a few minutes with your DVOM. If that's not for you, it needs to go to somebody who is qualified to read well, and recite ohms law, without a cheat sheet. (Unless they can draw their own cheat sheet... That's plenty for something this basic).

Either way, it should be a pretty straight up diagnosis, with limited and finite outcomes. Nothing's cheap these days, but the "crazy expensive" options are really not very high on the list.
 
Either way, it should be a pretty straight up diagnosis, with limited and finite outcomes. Nothing's cheap these days, but the "crazy expensive" options are really not very high on the list.

Except you'll likely pay $100 for a $12 sensor, which I do consider crazy, and if paying for installation more like $200.

Brian
 
That's cheap for car repairs. It costs 200 dollars just to open the hood. If that were my car (and it's not...), being as it's still got (theoretically) half it's life left to go, I'd probably seek out the hundred dollar sensor. Not by the price, but by the OES component. And/or a problem solver of some known life span/failure rate if there were a known issue with the original. There's nothing more expensive in the world of automotive repair than cheap parts. I think access to that switch is on the wrong side of things too (I could be wrong...), but I'd guess three hundred, or three and a half, out the door. (I'm thinking that, I'm not 100 percent on which side of the motor that switch is actually on). Unless, as I said, it goes to the shop with a cheap labor rate, with techs who diagnose by google. That raises the bill exponentially.

Besides, those were 134A cars, so it's probably a GM "lego" sensor that fits three quarters of everything they made in the last twenty years. Eighty bucks maybe for the OE, Forty for the one that one out of five times leaves you with a one year or two leak that nobody can ever find, because the worn out second hand dies they use to crimp the sensor don't load the seals correctly, and leave a leak that is to fine to let out a stain, and too faint for all but the best "sniffers". Five years out, on average, that cheap repair has a tremendous cost.

Sure, on an end of life vehicle, it might be worth a gamble if you can save something tangible at the end of the day. If you've still got a good, trustworthy car with some good miles ahead of it, you don't have to stack up too many inexpensive parts to turn it into a full on unreliable.
 
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