Wont start trying to reset the CPU?

Tiny
COACH HARVEY
  • MEMBER
  • 2013 CHEVROLET EXPRESS
  • 6.0L
  • V8
  • 2WD
  • AUTOMATIC
  • 115,000 MILES
I have replaced:
Cats,
Fuse Box,
MAP sensor
MAS sensor
All oxygen sensors,
fuel pump,

I am now trying to reset the CPU but when I do what you say to do when I hook up the battery all my radio presets are still there. Doesn't this tell me the reset did not work?
Car still will not start after reset, but radio still has presets.
Saturday, November 29th, 2025 AT 12:53 PM

8 Replies

Tiny
COACH HARVEY
  • MEMBER
  • 6 POSTS
Also replace plugs and wires. Van has fuel pressure and spark.
I had the cats off and was driving it to the muffler shop and the engine just died. Has never started back up. After I did the CPU reset the crank seemed a little different as if it was going to try to start for about 1 second then just went back to a crank only.
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Saturday, November 29th, 2025 AT 4:57 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,601 POSTS
Lets go over this video to see what is going on.

https://www.youtube.com/watch?v=lXLJbuAZ4CE&t

This video will show you how to do the system reset.

https://www.youtube.com/watch?v=INiDRO5A5MY

Also, does the engine sounds normal while cranking? If not you could have internal engine problems, to be sure if you upload a short video from under the hood while cranking I can tell for sure. You can do so in your response. Please go over these guides and get back to us.
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Monday, December 1st, 2025 AT 9:46 AM
Tiny
COACH HARVEY
  • MEMBER
  • 6 POSTS
I think the best info is I was driving it to the muffler shop with the exhaust system off. Made it around 2 miles and the engine just shut off. Never started again. Before this I was having on and off problems with it starting. It's been to three mechanics and a muffler shop. One most expensive shop said it was a fuel issue and replaced the pump. It was not the problem. Then they said it was the cats. I took the car back and replaced them myself. They were really, really bad but replacing them did nothing. I'm already into the repair around 4K and pretty much at my stopping point.
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Monday, December 1st, 2025 AT 1:15 PM
Tiny
COACH HARVEY
  • MEMBER
  • 6 POSTS
I also did everything that was in the video with no success about a vehicle not starting. I keep hoping I see a wire loose but with no luck. One side note. When I was working on the van I noticed the ground to the battery was not threading as it was stripped out. Not sure why none of the mechanics caught that but they did not. I replaced the nut and now I have a solid connection to the battery.
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Monday, December 1st, 2025 AT 1:17 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,601 POSTS
Yes, a lose connection at the battery can cause the engine to stall out. If you run the codes now do any come up, this guide can help us see if any codes are present.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Also, I can tell you this kind of problem is tough to find. When they replaced the fuel pump did they replace the relay as well? Also, I have seen an ignition switch short out and cause the engine to stall as well. Please go over this guide and get back to us.
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Tuesday, December 2nd, 2025 AT 9:12 AM
Tiny
COACH HARVEY
  • MEMBER
  • 6 POSTS
Ya I was thinking about the ignition switch. Is there anyway to bypass the ignitions to see if that is the issue?
Chevy's (not my year) had a recall for bad ignitions switches.
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Tuesday, December 2nd, 2025 AT 10:20 AM
Tiny
COACH HARVEY
  • MEMBER
  • 6 POSTS
Here are some of the codes that showed:
p0050
p0056
p0030
p0036
There also was a timing code that's why I replaced the crank shaft timing sensor. Cant remember the code.
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Tuesday, December 2nd, 2025 AT 10:24 AM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,601 POSTS
Yes! We have found the problem, with all of these codes

P0030 - HO2S Heater Control Circuit (Bank 1 Sensor 1)
P0036 - HO2S Heater Control Circuit (Bank 1 Sensor 2)
P0050 - HO2S Heater Control Circuit (Bank 2 Sensor 1)
P0056 - HO2S Heater Control Circuit (Bank 2 Sensor 2)

and the engine not starting you have an: engine control relay that is bad, one of the fuses in the image blow is out or you have a bad PCM. Lets start with the (run) relay which is in the fuse panel on the left side of the dash board. Please check the images below for more information. Check out the images (below). Let us know what you find.
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Wednesday, December 3rd, 2025 AT 9:16 AM

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