"Reduced Engine Power" - P228C

[Marshy]

Hi, new to the forum and have been search related issues and seeking help.  

 

I'll try to keep this short... this past Monday I purchased a used 2020 Silverado 2500HD, 6.6L Gas engine with 32,000 miles on it. I picked it up and drove 9 miles to the gas station to top it off. My wife was following me and she said she heard some rubbing noise from the truck. I didn't hear anything within the cab on the drive. I left the gas station and could hear a rhythmic rubbing from what sound like the rear pass tire/brake. I figured they much of messed something up when they inspected the brakes. A few hundred feet later I received a service parking brake and a reduced engine power message. It didnt make sense to me that the reduced engine power would be related to the parking brake message, but I continued home 7 miles. I texted the salesman that night and let him know about the message and would have it there tomorrow morning. In the morning, the check engine light was off and so was the reduced engine message. I drove the ~15 miles back without the message coming back on. I did not notice anything abnormal with the engine on startup, idle, or while driving.  

 

Talking with the Service Manager, the code was P228C - Fuel Pressure Regulator Exceeded Control Limits. According to the SM, they are working with a GM engineer and need to provide diagnostic data to help determine the issue. They are also going to take a fuel sample and perform an analysis. Best estimate for fixing is middle of next week. 

 

Anyone have any similar issues with the L8T engine? I believe 2020 was the first year for these trucks and I'm leery of buying the first gen of any new product but this truck is 5 years old and 32,000 miles so I figured any issues should be already addressed. I'm seriously looking into the Lemon Laws to see if this will qualify as a lemon vehicle. Any insight is appreciated, thanks. 

 

 

Edited February 27, 2025 by Marshy

[Pryme]

Sorry you’re having trouble with your new to you truck. Read up on lemon laws as your single issue is not even close to what’s required before a vehicle is deemed a lemon. 
 

what you’re experiencing is a single problem. 

[red44]

Hey man, that’s rough—sorry you’re dealing with this right after buying the truck. I’ve got a buddy with a 2020 L8T who had similar gremlins (his threw a P228C last year). Turned out to be a wonky fuel pressure sensor, but his dealer dragged their feet for weeks blaming “bad gas” first. 

 

Couple thoughts:

• The fact the code cleared itself is kinda sus. Could be a fluke, but these trucks are notorious for electrical gremlins. Make sure they check ALL the wiring/connectors around the fuel system. My buddy’s truck had a chewed-up wire harness (thanks, rodents…) causing intermittent chaos.
• The parking brake warning + noise? Maybe coincidence, but have them double-check the rear brakes anyway. Could be a seized caliper or debris—would explain the rubbing.
• Lemon laws for used vehicles are hit-or-miss depending on your state. If they can’t fix it after 3-4 tries, then you might have a case. For now, document EVERYTHING. Texts, service slips, even a video if the noise comes back.
• If the dealer gives you the runaround, call GM Corporate directly. Sometimes lighting a fire under corporate gets things moving faster than the local shop.

 

Hang in there—hopefully it’s just a sensor or something dumb. Keep us posted!

[Marshy]

15 hours ago, Pryme said:

Sorry you’re having trouble with your new to you truck. Read up on lemon laws as your single issue is not even close to what’s required before a vehicle is deemed a lemon. 
 

what you’re experiencing is a single problem. 

Yes, I have read some, but it was not abundantly clear if this would qualify. Under Duty to Repair it says;

 

A reasonable chance to fix the problem is considered to be either of the following: 

- Three or more attempts have been made to repair the car and the problem continues to exist.
- The car is out of service by reason of repair for a cumulative total of 15 days or more (although unavailability of parts may extend this time).

 

It's unclear to me if you need to meet both these conditions or just one. My friend's wife is a lawyer, I will be discussing with her to see if my situation applies. 

 

I believe if you decided to go the Lemon Law route it will involve lawyers regardless.  

[Marshy]

14 hours ago, red44 said:

Hey man, that’s rough—sorry you’re dealing with this right after buying the truck. I’ve got a buddy with a 2020 L8T who had similar gremlins (his threw a P228C last year). Turned out to be a wonky fuel pressure sensor, but his dealer dragged their feet for weeks blaming “bad gas” first. 

 

Couple thoughts:

• The fact the code cleared itself is kinda sus. Could be a fluke, but these trucks are notorious for electrical gremlins. Make sure they check ALL the wiring/connectors around the fuel system. My buddy’s truck had a chewed-up wire harness (thanks, rodents…) causing intermittent chaos.
• The parking brake warning + noise? Maybe coincidence, but have them double-check the rear brakes anyway. Could be a seized caliper or debris—would explain the rubbing.
• Lemon laws for used vehicles are hit-or-miss depending on your state. If they can’t fix it after 3-4 tries, then you might have a case. For now, document EVERYTHING. Texts, service slips, even a video if the noise comes back.
• If the dealer gives you the runaround, call GM Corporate directly. Sometimes lighting a fire under corporate gets things moving faster than the local shop.

 

Hang in there—hopefully it’s just a sensor or something dumb. Keep us posted!

Thanks. They seem to be working towards resolution but I'm not 100% sure, because when I talk to the Service Manager he doesn't know a lot of details on where they stand with exact diagnosis. He said they are working with a corporate GM engineer, and they need to log some data and provide it to him. Seems weird to me they need help from the GM engineer... I asked when they would have all the data provided to the engineer, he didnt know. He said they needed to provide a fuel sample, I asked if the sample was drawn, he didnt know. I started a written log of my phone calls to capture details. I'm getting a loaner vehicle today so will have a chance to meet the SM face to face. I feel like they are busy and trying to work on this "on the side" while keeping their other work flowing and do not have a person dedicated to working this start to finish. 

 

I think the brake noise and service parking brake message is obviously unrelated to the P228C code and just coincidental when it came on. They went thought the brakes a day or two before I picked the truck up so I believe something is wrong with the reassembly, not exactly sure. 

Edited February 28, 2025 by Marshy