2015 Silverado Flashing Check Engine Light - No Engine Power

jbreeds09 · January 14, 2016

Hi all,

I have had my 2015 Silverado 5.3L Crew for less than a year, purchased February 2015. Currently, the truck has around 14800 miles on it, most of which are highway miles as I make frequent trips between Atlanta and Florida. Today on my way to work in Atlanta my truck just gave out on me power wise, no acceleration passed 40 mph. The check engine light came on and started flashing repeatedly which the Chevy site indicates that to mean there is a serious problem that needs immediate attention. Well I was a very short distance from the dealer near work so I just maintained my speed and tried not to let the truck shift gears. Once I got off the highway I had to come to a stop and experienced really rough idle and some hard knocking sounds. The truck did not however seem like it wanted to die out or stall on me. When the light turned green I pressed the gas and had very weak acceleration, the truck was hardly picking up speed and I couldn't tell what the trans was doing. Anyway, I got it around the corner to the dealer and dropped it off.

I am hoping its just a computer module or something that gave out and started affecting things but it honestly seems more to me like a serious mechanical issue. Does anyone have any similar experiences or have any speculation into the issue? The transmission in this truck has always been the thing I liked least about it, sluggish shifts, not knowing what gear it wants to be in, hard shifts and knocking/dropping sounds. Any info or experiences would be appreciated.

Thanks,

Jeremy

fondupot · January 14, 2016

When the light flashes like that it means some sort of mechanical damage is occurring. It also puts the truck into limp mode which is why you had no power.

You really should have pulled over, shut the truck off, and called a tow.

jbreeds09 · January 14, 2016

Yea, that is what I figured from my research by now. Luckily I drove it less than 3 miles. Sounds like I have some cylinders sticking or misfiring.

onthepipe · January 15, 2016

I have a 2015 LTZ w/ less than 5K miles and my truck did this to me at 80MPH on a busy highway. I was lucky enough to get off the road enough to prevent an accident. Had to be towed to the dealer as it would not start after that. It ended up being the high pressure fuel pump and the part had to be ordered. Once we got the truck to the dealer, it would start but extremely rough idle. Pretty sad for <5K on the vehicle. Runs fine after the replacement though and I really do like the truck. We'll see how it hold up over the long haul.

jbreeds09 · January 15, 2016

Thanks for sharing your experience. Dealer got to my truck late in the day as they had existing jobs that needed finishing. They said the knock sensor went bad and that threw of the timing of the engine. I'm not 100% that's the full issue but I will provide an update after they get the part in on Monday. For now I am in a cute little Chevy Sonic as it was the only loaner they had left haha

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TJay74 · January 15, 2016

I find it hard to believe a knock sensor caused the issue. The only thing the knock sensor does is tell the ECM if a knock event is being heard, if it does it will put the truck into the low octane timing map until the knock event goes away. It will retard the timing as well, but even at the max retard values I have seen the truck should have still been driveable and not in limp mode.

Hopefully they will have more thorough news today for you.

jbreeds09 · January 19, 2016

So I picked up the truck from the dealer last night and I instantly noticed a difference in idle and ride quality from the month before leading up to the problem. It was like I hopped into a new truck after the dealers repair. I don't see any mention of replacing the knock sensor in the work order like they had originally mentioned but the mechanic replaced 4 lifters that went bad. I was asking him about the cause of the problem and he pointed me to a service document GM has open for the 5.3L engines (which matched my conditions and issues):

I have attached a section of it below.

Engine Misfire/Tick Noise, Malfunction Indicator Lamp (MIL) On, DTC P0300 Set

Condition

Some customers may comment on a malfunction indicator lamp (MIL) on and/or an engine misfire/tick noise.

Technicians may find DTC P0300 set or in history.

Cause

This may be the result of an active fuel management (AFM) lifter that is mechanically collapsed and/or stuck all of the time.

This may be the result of internal locking pin damage in the lifter. Due to oil aeration.

Correction

If SI diagnosis does not isolate the cause of this concern, technicians should inspect for valve operation.

If the valve(s) are not moving, replace the valve lifter oil manifold and affected bank of AFM lifters. Refer to Valve Lifter Oil Manifold Replacement and Valve Lifter Replacement in SI.

If the lifter has spun the bore, the guides should be replaced also.

Pokes2012 · April 17, 2016

Oil aeration? Was your engine oil over filled? Or did they say.

Pokes2012 · April 17, 2016

I find it hard to believe a knock sensor caused the issue. The only thing the knock sensor does is tell the ECM if a knock event is being heard, if it does it will put the truck into the low octane timing map until the knock event goes away. It will retard the timing as well, but even at the max retard values I have seen the truck should have still been driveable and not in limp mode.

Hopefully they will have more thorough news today for you.

Do you happen to know what "engine map" the truck reverts back to every time you start it? For instance if you put a lower octane fuel in and the knock sensor has to retard the timing will it stay that way indefinitely or can it sense when higher octane fuel is added on lets say the next fill-up.

karpetkutter · April 17, 2016

I had a similar experience with my 15 5.3 Silverado and the dealer said it was two fouled plugs. Since they changed the plugs hasnt been an issue.

TJay74 · April 19, 2016

Do you happen to know what "engine map" the truck reverts back to every time you start it? For instance if you put a lower octane fuel in and the knock sensor has to retard the timing will it stay that way indefinitely or can it sense when higher octane fuel is added on lets say the next fill-up.

On start up the truck will be in the high octane map until a knock event is detected, then it will drop down to the low octane table and stay there until the event decays out. There is also a table for E85 as well that is used if the alcohol sensor detects enough alcohol in the gas.

jbreeds09 · April 19, 2016

Oil aeration? Was your engine oil over filled? Or did they say.

Unfortunately, I don't think they said or I don't remember since its been three months ago.

2SS/RSD · April 21, 2016

I had a situation like that, dealer replaced #1 spark plug wire and plug. Works fine now. The dealer was the only real problem!

ChevySilveradoLTZ · July 22, 2017

Ok I am having the exact same problem as you and made a topic it about TODAY. My truck idles rough like you said with the engine light flashing and the oil gauage dropping. How much did it cost to repair?