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The service indicator came on yesterday and stayed on for my few trips. Today it didn't come on. I am barely over 4900 miles so not even near the first servicing time. My dash just said service was due soon.

Has anyone else had this happen? Otherwise my Bolt is driving fine.
 

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Mine has 14K miles and has not notified me of any service due. Are you
sure you have a Bolt ? LOL!
 

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Probably not a service due soon situation, but rather a component of of the car has indicated that it is encountering problems and needs to be checked out by the dealer to ensure continued safe operation. I’m willing to bet that it was the MIL (malfunction indicator light) that came on. I just went past the 7500 mile mark and no “maintenance required” light came on to remind me to rotate my tires.
 

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I had one when trying to shift from PARK and my HVAC GUI controls stopped toggling and indicating. I'm guessing something HVAC related (either cabin or traction battery cooling related) didn't report status correctly and the car wouldn't let me drive. HVAC GUI controls were not working, but the manual controls appeared to be as I still could change fan speeds and felt heat.
 

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The service indicator came on yesterday and stayed on for my few trips. Today it didn't come on. I am barely over 4900 miles so not even near the first servicing time. My dash just said service was due soon.

Has anyone else had this happen? Otherwise my Bolt is driving fine.
Yes - my Service Engine Soon light has come on twice now, the first time after about 30 days (April 2017) at 1,800 miles and then again
on 10/23/17 at 10,700 miles. Both times there were no known visible issues, the car ran fine and all the controls
were functional.

Both times I dropped the car off at the dealer, they ran diagnostics, updated and/or reprogrammed the HPCM2 (Hybrid/EV Powertrain Control Module 2),
whatever all that means, and I was back on the road.

Codes:
1st time: U18A4 - Lost communication with Hybrid/EV Battery DC Charging Communications Gateway Module
2nd time: P3021 - Hybrid/EV Battery DC Charging Negative Voltage Sensor Stuck Low

Hopefully this is the worst I'll experience...
 

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Yes - my Service Engine Soon light has come on twice now, the first time after about 30 days (April 2017) at 1,800 miles and then again
on 10/23/17 at 10,700 miles. Both times there were no known visible issues, the car ran fine and all the controls
were functional.

Both times I dropped the car off at the dealer, they ran diagnostics, updated and/or reprogrammed the HPCM2 (Hybrid/EV Powertrain Control Module 2),
whatever all that means, and I was back on the road.

Codes:
1st time: U18A4 - Lost communication with Hybrid/EV Battery DC Charging Communications Gateway Module
2nd time: P3021 - Hybrid/EV Battery DC Charging Negative Voltage Sensor Stuck Low

Hopefully this is the worst I'll experience...
Thanks for adding your personal experience to the forum/knowledge base.

So after the service light went away and "the car ran fine and all the controls were functional", how long from then to your service dept visit? I have a service dept visit scheduled a week from now and am worried the error codes will go away. When your Bolt returned to normal, did the service light go away as well?
 
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Thanks for adding your personal experience to the forum/knowledge base.

So after the service light went away and "the car ran fine and all the controls were functional", how long from then to your service dept visit? I have a service dept visit scheduled a week from now and am worried the error codes will go away. When your Bolt returned to normal, did the service light go away as well?
My Service Engine light stayed on until the dealer visit, which was 5-6 days after the 1st time the light came on, and one day after the 2nd.
Even if the light was to go out, the codes will stay in memory until they are explicitly erased by the dealer.
 

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I checked the diagnostic page on mychevy.com. It updated our mileage, and ran whatever checks it does. Came back with all green boxes. Everything AOK. Don't know whether to be encouraged or discouraged by that. Anyway, made an appointment to take it into our local dealer to have them check for fault codes, on Monday. Have my fingers crossed.
 

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Just went out and turned it on, for the fourth time, and now the "Service Vehicle Soon" light is out. Won't get much rest between now and Monday afternoon. :-(
 

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If the light went out, it was a transient condition that is not continuing, so I wouldn't worry about it.

On mine, the car went in two weeks after the SVS light and a one-word message "Transmission", and they replaced the shifter, updated some code in the transmission, and reseated a couple of connectors that were apparently not firmly inserted.
 

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Went to the local dealer this afternoon. The service manager came right out with a laptop, and plugged it into the service port. The codes said the problem was with the battery relay in the High Power Distribution Module. The computer monitors the relays for open/close times. It took too many milliseconds to open once. The test procedure called for him turning the car on, and off ten times, in succession, with the diagnostic computer hooked up. It operated within specs those ten times, so we are good to go, until/unless it happens again. Sounds like I might want to carry a rubber mallet, in case it sticks and hangs. Only half kidding. :)
 

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Even if the light was to go out, the codes will stay in memory until they are explicitly erased by the dealer.
Not 100% sure on the Bolt but historically GM firmware clears many codes after xx number of successful key-on, key-off events to not confuse diagnostics in the future with stale codes from the distant past...

Edit: and almost to prove my point the post above this explains how "10 key on key off" events "fixed" his issue ;-)
 

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The computer monitors the relays for open/close times. It took too many milliseconds to open once.
It's hard to know whether to be happy about the extensive checking that the car is doing or to be incredibly annoyed at how sensitive it is to transient problems...

It seems to me that they could do a better job of logging these exceptions for later diagnosis and not bothering the driver about them unless they actually become some sort of operational issue.
 

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It's hard to know whether to be happy about the extensive checking that the car is doing or to be incredibly annoyed at how sensitive it is to transient problems...

It seems to me that they could do a better job of logging these exceptions for later diagnosis and not bothering the driver about them unless they actually become some sort of operational issue.
I am definitely glad they are monitoring everything. As for being kept in the dark about it, I prefer to know what is going on. What is frustrating is the sense of impotence that solid state electronic devices give. If this thing had old magnetic relays, with contactors, the failure rate would be higher, but you could look at it, see the stuck contactor, or see the soot around the offending one, and sand it with a match book striker, and get home. An SSR, like everything solid state, is a magic rock. If you pulled the cover off the HPDM, you might see soot, if the SSR had cooked completely, but everything is potted in epoxy, and nothing you could jerry rig anyway.
 

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I am definitely glad they are monitoring everything. As for being kept in the dark about it, I prefer to know what is going on. What is frustrating is the sense of impotence that solid state electronic devices give. If this thing had old magnetic relays, with contactors, the failure rate would be higher, but you could look at it, see the stuck contactor, or see the soot around the offending one, and sand it with a match book striker, and get home. An SSR, like everything solid state, is a magic rock. If you pulled the cover off the HPDM, you might see soot, if the SSR had cooked completely, but everything is potted in epoxy, and nothing you could jerry rig anyway.
The solid state electronics are actually an order of magnitude easier to see and tell what is going on vs. an older mechanical system though. While you're not going to "pop the cap" and inspect a silicon junction, the failures at the junction level are so rare as to be virtually immaterial. The interaction between components and monitoring and management ability is where all the magic happens, and that is where solid state electronics have their gigantic troubleshooting advantage. The artificial barriers that make modern cars "difficult" to troubleshoot are almost all a product of OEM rent seeking and obfuscation by unnecessary proprietary methods. Sad state of affairs for the average owner currently.
 

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It's hard to know whether to be happy about the extensive checking that the car is doing or to be incredibly annoyed at how sensitive it is to transient problems...

It seems to me that they could do a better job of logging these exceptions for later diagnosis and not bothering the driver about them unless they actually become some sort of operational issue.
GM has "maturation" rules for every code that could light the MIL. IE if things could happen a few times before telling the driver or how many events before lighting the light, are the events sequential or are they spaced apart, you get the idea.

An exception is Safety related. If somehow the event that occurred could ever potentially be a safety issue the issue may only need to happen once to set a code and warn the driver.
 

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I have yet to get a code on my Bolt. But with my other cars, if I get a service light I go to my neighborhood O'Reilly's and they hook up a reader and print out the codes for free. I had a complete $etup for gen 1 back in the day. Still use it for my older vehicles. But started getting the free diagnostics from the parts store once gen 2 came out.
 
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