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2018 Battery Energy Control Module (BECM)

41852 Views 138 Replies 63 Participants Last post by  vap3
Hopefully this isn't a redundant thread but all I could find were threads on 2017 BECM failures.

I'm kind of curious how prevalent 2018 BECM failures are.

Mine occurred at 36,270 miles (300 after BtB warranty expired) and 3 weeks shy of 3 years.

Symptom:
Cruising at 30 mph, engine warning light came on. Battery charge level went from about 60% to 100% charge. Engine started. Shut down car and exited for about 30 minutes.
Upon restart, engine warning indicator remained illuminated (solid, not flashing) and charge indication was normal.
During 20 mile drive to shop, all normal (except engine fault indication).

Finding:
5 fault codes (stored but inactive) indicating BECM. (I didn't get a list of the codes.)
Shop credited the $160 diagnostic fee. Parts available. Be at shop a couple work days.

Questions:
1) The mechanic said that they've seen quite a few BECM failures for all MY gen 2s. Any other 2018 owners out there that have had failed BECMs?
2) Is it normal for a shop to replace (under warranty) an intermittently failed part, or is this just good shop?
3) I assume that the Battery cooling system fluid needs servicing after dropping the battery to replace the BECM. Does anybody know if they would flush it or just burp/service it? Is the BECM on the electronic cooling loop or the battery loop? If the former, same question about flush or service. (Obviously, I would hope for flush so I could zero time those loops.)

Thanks in advance for any feedback. (And moderators, if there are 2018 BECM threads or threads similar to this, please feel free to merge them.)

Regards,
Chris
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Glad to hear Yes I do like the car and also had a loaner paid for by the dealership. It seems the supply is picking up
I'm glad yours finally arrived. I am just starting this process. My biggest problem is finding a dealer who has the equipment to drop the battery and replace the module. I had to call about 12 dealerships just to find one that stated they had the tools/manpower to be able to remove/replace the hybrid battery and the dealer is 150 miles away.
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My car has been at the dealership since Sept 21 waiting on a BECM replacement. They called me 2 weeks ago and said the BECM had finally came in but now they were waiting on some clips that were one time use to come in. I have been given a loaner car by the dealership which has been very helpful but I I’m ready to get my car back.
My car has been at the dealership since Sept 21 waiting on a BECM replacement. They called me 2 weeks ago and said the BECM had finally came in but now they were waiting on some clips that were one time use to come in. I have been given a loaner car by the dealership which has been very helpful but I I’m ready to get my car back.
Wow! you got a loaner vehicle. Those are rare as hens' teeth nowadays.
After exactly 11 weeks to the day my BECM is finally replaced and I was able to pick up my car from the dealer today. Sure am glad to get it back! Build date on my car is 9/2017
Last Sunday got a CEL in my 2018, battery meter going wonky, drove in hold mode. Just over 30k mi on the odometer. Took it in to the dealer Monday, Tuesday I get the call, BECM needs replaced and they were able to actually find one at another dealership. Service writer was telling me how lucky I was, if he couldn't get that one, I'd be sitting for a while. Should have it back Thursday.
Last Sunday got a CEL in my 2018, battery meter going wonky, drove in hold mode. Just over 30k mi on the odometer. Took it in to the dealer Monday, Tuesday I get the call, BECM needs replaced and they were able to actually find one at another dealership. Service writer was telling me how lucky I was, if he couldn't get that one, I'd be sitting for a while. Should have it back Thursday.
Great! I got lucky as well! My car is fixed! It didn't take as long as I thought. I think I got lucky because they said they found a new BECM at another dealership. My car was out of service from 11/10/21 until 12/8/21, but I am thankful because many others have waited a lot longer for the part.
I know this is a bit old, but I'm adding my 2018 to the list of BECM failures - mine happened at 81,000 miles. Dealership is covering a rental for me in for the time being, but they expect the part to be here in two weeks...fingers crossed!
For what it’s worth… I just found out today that they now have the part… 7 week wait. I’m selling when it’s fixed. Don’t trust this car anymore. Unfortunate because I really liked it for the first two years
I think you convinced me to go ahead with my Ioniq5 pre-order. I have a 2018 Volt too. I guess i could ride out the 8 year warranty but resale prices are great now. Did you get your BECM replaced and did GM cover the rental for 7+ weeks? $4300 out of warranty Yikes!!!!!!!!!
Do you'll plug it every night? Or do charge every other day or two or three? Do you wait till the charge is at zero?
Do you'll plug it every night? Or do charge every other day or two or three? Do you wait till the charge is at zero?
I charge twice a day. My daily commute is 26 miles each way. I plug in when I get to work and when it’s time to go home I have a full charge. When I get home I plug in again and have a full charge for the next morning.
Do you ever use hold mode? Using car always in electric mode seems to waste the engine unless you use an oil and gas preserver? I think if you don't use the engine you'll lose it? Does that make sense? Feedback is appreciated....
I’ll use hold mode when I know I’m going farther then the battery range. I’ll drive in electric mode to get to the interstate then switch to hold mode then back to electric mode to use the rest the battery up as I arrive at my destination. The car is smart if you drive in electric mode for a long time the car will do a maintenance run after a few months just to run the engine for maybe 10 minutes or so. It also tracks how long the gas has been in the tank, when it determines the gas has been in the tank for to long it will start the engine and burn up the gas before it gets to old. I usually try to only keep a gallon or two in my tank because I can go for months without using the engine. No need to haul around all that extra weight.
Hopefully this isn't a redundant thread but all I could find were threads on 2017 BECM failures.

I'm kind of curious how prevalent 2018 BECM failures are.

Mine occurred at 36,270 miles (300 after BtB warranty expired) and 3 weeks shy of 3 years.

Symptom:
Cruising at 30 mph, engine warning light came on. Battery charge level went from about 60% to 100% charge. Engine started. Shut down car and exited for about 30 minutes.
Upon restart, engine warning indicator remained illuminated (solid, not flashing) and charge indication was normal.
During 20 mile drive to shop, all normal (except engine fault indication).

Finding:
5 fault codes (stored but inactive) indicating BECM. (I didn't get a list of the codes.)
Shop credited the $160 diagnostic fee. Parts available. Be at shop a couple work days.

Questions:
1) The mechanic said that they've seen quite a few BECM failures for all MY gen 2s. Any other 2018 owners out there that have had failed BECMs?
2) Is it normal for a shop to replace (under warranty) an intermittently failed part, or is this just good shop?
3) I assume that the Battery cooling system fluid needs servicing after dropping the battery to replace the BECM. Does anybody know if they would flush it or just burp/service it? Is the BECM on the electronic cooling loop or the battery loop? If the former, same question about flush or service. (Obviously, I would hope for flush so I could zero time those loops.)

Thanks in advance for any feedback. (And moderators, if there are 2018 BECM threads or threads similar to this, please feel free to merge them.)

Regards,
Chris
2018 Premier
Hopefully this isn't a redundant thread but all I could find were threads on 2017 BECM failures.

I'm kind of curious how prevalent 2018 BECM failures are.

Mine occurred at 36,270 miles (300 after BtB warranty expired) and 3 weeks shy of 3 years.

Symptom:
Cruising at 30 mph, engine warning light came on. Battery charge level went from about 60% to 100% charge. Engine started. Shut down car and exited for about 30 minutes.
Upon restart, engine warning indicator remained illuminated (solid, not flashing) and charge indication was normal.
During 20 mile drive to shop, all normal (except engine fault indication).

Finding:
5 fault codes (stored but inactive) indicating BECM. (I didn't get a list of the codes.)
Shop credited the $160 diagnostic fee. Parts available. Be at shop a couple work days.

Questions:
1) The mechanic said that they've seen quite a few BECM failures for all MY gen 2s. Any other 2018 owners out there that have had failed BECMs?
2) Is it normal for a shop to replace (under warranty) an intermittently failed part, or is this just good shop?
3) I assume that the Battery cooling system fluid needs servicing after dropping the battery to replace the BECM. Does anybody know if they would flush it or just burp/service it? Is the BECM on the electronic cooling loop or the battery loop? If the former, same question about flush or service. (Obviously, I would hope for flush so I could zero time those loops.)

Thanks in advance for any feedback. (And moderators, if there are 2018 BECM threads or threads similar to this, please feel free to merge them.)

Regards,
Chris
2018 Premier, 36700 miles. Just started showing what I expect to be symptoms related to a failing BECM. CEL came on, no driveability issues. OnStar error codes...p1e00,U2619,30,21,22,23, and U2624. Would only charge for a few minutes at a time, but finally fully recharged from 95% to 100%. Day 2 -- drove a few miles normally except for CEL. Same charging problem, but did get car recharged to 100%.
Day 3 -- CEL not on!?! (No codes from OnStar). Drove 5 miles, EV miles dropped to zero, ICE came on and "reduced propulsion" message and CEL back on. (Same codes from OnStar)
Today -- still trying to recharge. When recharging, EV range shows correct miles. When charging shuts down, EV range shows zero miles but 100%.

Have service appointment on Monday (today is Wednesday).

I just connected my Battery Tender to the 12 volt battery -- wondering if it too is not being charged!?!

Not sure about build date -- I found a silver label drivers side door sill showing 10/17.


Will edit/add to this reply as more info is forthcoming.


Bob
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What's the longest you been without charging it? When it was working? Did you put it in low of low and sport slot?
What's the longest you been without charging it? When it was working? Did you put it in low of low and sport slot?
A failed BECM is a failed computer. It has no relation with how often a car was charged, the mode used, or the health of the battery itself.
A failed BECM is a failed computer. It has no relation with how often a car was charged, the mode used, or the health of the battery itself.
Ahhh!
I wish I would have found this thread earlier. I have a 2018 volt, just under 30k miles. Similar problems as many on here. Check engine light went on. I was getting unable to charge messages. Went in to reduced propulsion a couple of times. I was able to keep charging by plugging it in and I was able to drive it. I made an appointment and took it in and it's the BECM. The rep told me that there is a shortage and the last time this happened it took 4 month's to get a new one in. That's crazy. It is covered under the voltec warranty and they got me a rental, but what a hassle. This should not break down in less than 30k miles. That's not good. Like another person wrote in it makes me think what else will go wrong. I do like the car. I am hoping this is the only thing wrong. Now I have to drive a gas car to work. I was able to plug in for free at work, but if this takes 4 month's it's going to cost me some money. Might have to go with a tesla next time. lol
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A volt tech on one of the volt Facebook groups has mentioned a couple times that the reason for failure of these modules is down to failed solder joints. It would certainly explain the randomness when it starts to fail.

The new part is said to be redesigned as to not have this problem. He also mentioned he has never seen a replaced unit come back.
Just had this happen to my 2018 LT @ 49,000. Check engine light one day followed by a no start condition. After switching to neutral, I was able to start the car. Engine imediately fired up with 0 miles of range but full battery. At dealer now with no eta on the BECM.
Just had this happen to my 2018 LT @ 49,000. Check engine light one day followed by a no start condition. After switching to neutral, I was able to start the car. Engine imediately fired up with 0 miles of range but full battery. At dealer now with no eta on the BECM.
Just a bit of background. I charge twice daily during the week, drive in D most of the time and the vast majority of miles are highway.
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