2013 Silverado 1500 P0641 & P069e

[Tyler Raumer]

My truck is a 2013 Silverado 1500 LT with the 5.3 Flex fuel engine.

 

 

 

I was driving home yesterday and my check engine light starts flashing along with ABS and traction control lights. The truck started to misfire and shake, I scanned the codes and got P0641 and P069E. Eventually the check engine light stopped flashing and the truck started to run better (still misfiring but without the vibration and flashing CEL). I immediately suspected the fuel pump as the truck has 176,000 miles (150,000 of those pulling a trailer).When we got home I hooked a mechanical fuel pressure gauge up to the Schrader valve and got these results.

 

 

 

Key on engine off - 60psi

 

Engine running at idle - 42-44 

 

 

 

I also check the fuel pressure with My scan tool while driving and had around 44psi.

 

 

 

I cleared all the codes and we drove around for about 15 minutes and the only code that came back was a cylinder 3 misfire. The truck will still runs and drive now but it's obvious there is a misfire anytime we stopped or let it idle in park.

 

 

 

Tomorrow I plan on replacing the fuel pump but I'm still not 100% sure that's the issue, any help would be appreciated.

 

 

 

 

[stu_pidasso]

When were the spark plugs last replaced? I bought a truck straight from auction with a P0301. It would idle rough at stop lights and stuff. Put a new batch of plugs in, now the truck runs like it just rolled off Arlington Assembly. 

 

Those fuel pressures are within spec. I know some stuff says 58 pounds running, and it should not run that much under no-load-pre-start charge (60psi), but 44 ain't bad. Fuel pumps either work, or they don't. 

 

The 69 (hehe) code is related to manifold pressure, and 641 has to do with a few grouped sensors that try to read a variable. This would be three wire sensors, sensors that would tell the PCM how much pressure, how much temperature, etc, not like a binary or on/off sensor that would tell the PCM a condition is met. Knowing that, and knowing 641 is coupled with P0069, I would look at the MAP sensor to start, things that tell the PCM whats going on in the manifold, MAF sensors, intake gaskets, air filter. ****** like that. 

 

The key to troubleshooting is to start small and eliminate the easiest, cheapest, and simplest part of the system thats giving you the problem. Work from the bottom up, not the top down. 

Edited July 8, 2022 by stu_pidasso