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I popped a CEL at the end of an 80-mile highway run on the ICE.

I didn't scan the codes, but the OnStar alert said it was emissions related. I took the car in and they told me the EGR valve failed (internal short) and it would take a day to get the replacement part in. Since I would only be driving on electric, I offered to bring the car back for installation of the EGR valve, but the Volt tech strongly advised against it. He said the EGR valve is tied to the Voltec system and since it has a short, he was concerned that it could damage the Voltec even if I was not using the ICE.

I took the Malibu loaner and went on my way. That night, I checked the Volt on the My Chevy app and noticed that the it was showing 0 miles range for the battery (the car was only down two bars when I dropped it off). I'm guessing that the EGR valve really is tied into the Voltec system to the point that they disconnect the battery as a precaution.

When I picked up the car, the invoice read as follows:

25177 DIGITAL EGR VALVE INTERNALLY SHORTED AND BLEW ECM FUSE. ROAD TEST AND SCANNED SYSTEM FOUND 13 CODES. TRIED TO CLEAR CODES ALL CODES CAME BACK. MOST OF THE CODES ARE ECM RELATED CODES. TRACED TO BLOWN FUSE THAT SUPPLIES VOLTAGE TO THE EGR DISCONNECTED AND FUSE STOP BLOWING. REPLACED DIGITAL EGR VALVE AND FUSE.
Nothing major to see here; I just thought it was interesting that the EGR valve is so closely integrated with the Voltec system.
 

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I just thought it was interesting that the EGR valve is so closely integrated with the Voltec system.
The car still drove for you on the battery, right?

I would think it's more likely that the myChevy app needs your ECM powered to properly report the car's true status to you. I wonder if the blown fuse was changed at the point you checked your app?
 

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The car still drove for you on the battery, right?

I would think it's more likely that the myChevy app needs your ECM powered to properly report the car's true status to you. I wonder if the blown fuse was changed at the point you checked your app?
The car seemed to drive fine on the battery but I had to clear a "reduced propulsion" message at each start up and there was a CEL. I spoke to the tech (not the service writer) and he was emphatic that driving on the battery could cause a problem.

I checked the app late in the evening, so I don't think they were actively working on the car at that point. The app accurately reported the air pressure in the tires and the gas range.
 

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The ICE is an integral part of the genset. If there is something wrong with the genset, software logic probably dosen't want you driving the battery down to "empty" with the possibility of no ability to recharge or continue in the CD mode, hence the "reduced propulsion" message. This is just one of a million ways the battery is protected, imho.
 
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The app accurately reported the air pressure in the tires and the gas range.
I don't think these are reported real-time and would expect they are reporting the last read values. For instance, the gas gauge should only be powered when the car is fully powered.


If there is something wrong with the genset, software logic probably dosen't want you driving the battery down to "empty" with the possibility of no ability to recharge or continue in the CD mode, hence the "reduced propulsion" message.
Maybe this could be similar to all the fits the car give us when the tank is low on gas?
 

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<snip>

Maybe this could be similar to all the fits the car give us when the tank is low on gas?
Agreed. The GM engineers tried to make the Volt bullet-proof and to prevent self-destruction wherever possible, imo.
 

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I had the same EGR short issue on a road trip from Houston to San Diego. Luckily, it failed near San Antonio so I towed it to a dealership.
according to the dealer, there were no EGR replacement valves available to fix the issue and after waiting two days in a hotel, we finally decided that I could drive it back to San Diego with the EGR valve disconnected. They gave me a handful of 15A fuses in case the fuse blew again. I’m now in El Paso and it seems to be working. One thing note, when the EGR valve blows, the ICE cannot cool itself so you get the reduced power warning because it’s overheating. Check the temp and make sure it’s <230 or so. I’m not pushing it on the way back and am constantly watching the temperature.
Still love my Volt but this EGR valve is definitely a weak point. Just wish it didn’t break on a road trip.
 

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I had the same EGR short issue on a road trip from Houston to San Diego. Luckily, it failed near San Antonio so I towed it to a dealership.
according to the dealer, there were no EGR replacement valves available to fix the issue and after waiting two days in a hotel, we finally decided that I could drive it back to San Diego with the EGR valve disconnected. They gave me a handful of 15A fuses in case the fuse blew again. I’m now in El Paso and it seems to be working. One thing note, when the EGR valve blows, the ICE cannot cool itself so you get the reduced power warning because it’s overheating. Check the temp and make sure it’s <230 or so. I’m not pushing it on the way back and am constantly watching the temperature.
Still love my Volt but this EGR valve is definitely a weak point. Just wish it didn’t break on a road trip.
Was it the F3 non walk home fuse that blew? Had that issue on my 2016 Volt. Still waiting for dealer (Keyes in Van Nuys) to get a new EGR valve. They said "no problem" driving on battery and I've been doing so for the past 3 weeks. When the engine ran I didn't notice any overheating. The reduce power warning displayed as did the check engine light, but there was no noticeable change in performance.
 

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Was it the F3 non walk home fuse that blew? Had that issue on my 2016 Volt. Still waiting for dealer (Keyes in Van Nuys) to get a new EGR valve. They said "no problem" driving on battery and I've been doing so for the past 3 weeks. When the engine ran I didn't notice any overheating. The reduce power warning displayed as did the check engine light, but there was no noticeable change in performance.
Yes. It was that fuse. The mechanic even made fun of the name of that fuse which I agree is strange. The engine will run with the EGR valve disconnected just fine. Of course the engine light is on.
I hope GM gets more of these valves in stock soon. I'm wondering if they're redesigning them to prevent this from happening again.
 

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One thing note, when the EGR valve blows, the ICE cannot cool itself so you get the reduced power warning because it’s overheating.
How does a Voltec 2 EGR valve effect cooling ?
 

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fails open and allows to much really hot exaust gases to go back into the combustion chamber, increasing the combustion chamber temp. the engine cooling system cant keep up with cooling it
 

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fails open
Ok. I was thinking it was staying closed/restricting flow because the coil for the actuator failed.

I am guessing then, that the failure mode is carbon buildup that is common on direct injection motors, causing the actuator to burn out ?

Do they simply need periodic cleaning and the dealers just replace them ?

What's the failure mode of the EGR Cooler ? leaks ?

Best option is likely a future EGR delete.

The motor is not used as much in a Gen 2 Volt... I assume they will eventually have the common "carbon buildup on valves" issue that most direct injection motors have. Any idea if/when the heads need to pulled to clean the carbon ? Do volt owners use GDI Intake cleaner for maintenance ?

Ya gotta love direct injection motors. Not.
 

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My EGR shorted at 11K miles, replaced under warranty but still fighting with GM for the 'Qualifying GM /Enterprise' vehicle rental costs......warranty work was done in 5 days....no real issue there
 
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