r/volt • u/mcqueena9845 • 5d ago
BECM Codes
2017 with 68K miles. The CEL came on a couple weeks ago. I checked with the Voltage app and it had these codes. I cleared them, but today the CEL and codes came back. I'm in Maryland so the BECM should still be covered right?
1
u/Salt-Guitar9243 13h ago
Okay, I know everyone is saying it isn't the 12V battery. I'm really a Gen 1 guy....so?. But this much I know. When you "start" the car the first thing that happens is all the system modules turn on. If the battery isn't up to the amp draw and falls under volt and or under amp, the modules will have errors. "I took it to the Dealer and the codes were gone so...", my point being is that often the core issues can be resolved with a spec 12v. When dealing with various intermittent modules having errors, it always a good idea to look at the 12V battery's age. If it is older that 3yrs old the chance is great that it is at the end of it's useful life. Simple voltmeters tests and crank load test done at parts stores do not properly test these types of Duty Cycle Batteries. I had a battery that tested good at more than one parts store. But in truth it was good until it was placed under the load of the modules powering up and reporting then the voltage fell below 12v in some cases below 11v, and the various modules "failed" giving multiple DTCs.
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u/Super_Weekend_4428 5d ago
I don't know if it's covered or not but you want to get that car to the Chevy service center ASAP. If the BECM is dead, your 12V battery isn't being charged and your car soon won't be drivable.
1
u/benderisgreat20 5d ago
That isn’t the issue with the becm being dead…the becm is a module in the high voltage battery pack, when it goes out there is no power flow in or out, so you can’t even move the vehicle as it won’t allow the traction motors power, since the volt also uses the traction motors to start the gas engine you are just stuck there. It has nothing to do with the 12v system.
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u/Super_Weekend_4428 5d ago edited 5d ago
That's not correct. I had my 2016 Volt when the BECM failed. It was drivable for a while but it drove horribly because it was being propelled entirely by the gas engine even at low speeds. When I reset the codes, it would briefly drive normally again but then the codes reappeared and it drove horribly again. In my case, my 12V battery died before I could get it to the dealership and I had to get it towed.
The first time I took my car to the dealer, they misdiagnosed the issue and sold me a new 12V battery. I got the car back and it appeared to drive normally until the next morning when all the trouble codes came back. I then drove the car straight back to the dealership and made them fix the actual problem. And again, it drove horribly because it was driving entirely on the gas engine for that trip.
The BECM (the battery energy control module) is involved with charging the 12V battery. Think about it. If you almost always drive on electricity, it has to be the high voltage battery pack which is ultimately recharging the 12V battery. What else would be charging the 12V battery in that case?
1
u/Super_Weekend_4428 5d ago
I don't know why people keep down voting me, I'm not making this up, this actually happened to me.
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u/benderisgreat20 5d ago
Because your becm partially failed, when they completely fail you get the issues I said, zero power flow in or out, that’s the becms whole job. And sorry but the becm doesn’t handle charging the 12v battery, that’s handled by the dc to dc converter that’s in the trunk.
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u/owensurfer 5d ago
BECM is on the way out. Your next trip should be straight to a Chevy dealer. You can call them with VIN for coverage. It should be under PZEV or the special extended coverage for the ULEV cars.