Help with some DTCs

Croatan_Kid

Croatan_Kid

How's your hammer hangin'?
Joined
Nov 4, 2007
Location
New Bern
I hooked up my scanner to my uncle's truck and pulled the codes on it. It's a 2006 GMC Sierra with a 5.3, stock, except an air intake. Shortly after I put it on for him, he had the intake tube pop off once or twice, no problems now though, but it always threw a MAF code. Finally got it on there good and tight.

Now then, it has since popped a few more. Two say they're old codes, the other two are new.

P0053
P0101
P0171
P0420

Sounds like an oxygen sensor to me, but I know that the MAF and O2 are run through the same fuse for some reason, so I'll check that out. Other than that, yall have any ideas?
 
P0053-02 sensor bank 1 sensor 1
p0101-MAF
p0171-bank 1 sys too lean
p0420-cat. convt. bank 1 below inefficiency

I'd start with the o2 sensor and reset the codes and go from there.
 
P0053 - 02 Heater Resistance (Sensor 1, Bank 1) driver's side, upstream of the cat
P0101 - MAF Circuit Range/Performance Problem
P0171 - System Lean, Bank 1
P0420 - Catalyst System Efficiency Below Threshold, Bank 1

Being a 2006, the truck has no EGR so don't let that throw off you're diagnosis. Other than the MIL staying on, the truck runs great and gets about 19mpg so says my uncle.
 
the 53 means that 02 sensor isn't working but then the 171 says it is working because its detecting a lean condition
with the 101 and 420 codes I would check for any vacuum leaks, spray carb cleaner around the intake and and vacuum lines, if it is a leak the idle will change when it sucks in the carb cleaner, and if not the check was nearly free.
 
Ha! He beat me to it! That was my first though, an 02 sensor. I'll pull a data log and check the voltages for the 02s and see what bank 1, sensor 1 looks like compared to the other side. They should read differently if one is bad.
 
Come to think of it, I'll check and see how many miles are on this jewel. If it's up around 130k or so, it could very well be the intake gaskets leaking a tiny bit. I'll shoot some carb cleaner around them and see what they do. It could be that only the driver's side gasket is sucking air. It'll definitely set a MAF code if it pulls air behind the MAF.
 
Will do. I'm certainly going to check it out as soon as I can. I've got a feeling that between an 02 and intake gaskets, it'll be resolved.
 
You can check oxygen sensors by creating a vacuum leak (pulling brake booster hose). If its not switching and holding lean you can add some propane after the maf, if the sensor is functional you should be able to make it go rich. Lt fuel trim is a learned value so you can use it to determine where in the rpm range its lean at and how lean it is. I would do a snap throttle test on the maf and make sure its not just dirty. What is the freeze frame showing? My 5.3l had a intake leak which was only present at cold start, once warm is disappeared the only way i caught it was the ect and loop status in the freeze frame.

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