Have a 2001 Chevy Blazer, 4WD, 4Door 4.3 liter engine.

Just installed a new fuel pump with help from a member from here. It starts up fine and it runs. That was a couple of days ago. Today, it started to show "service engine soon" warning. I bought a low price OBD scanner and it played off these 4 codes, P0101 P0102 P0452 and P0300

I looked at the reference book provided with the scanner for what the codes were referring to. The first two have something to do with the MAFS sensor, which I did install a new one a couple of months ago. P0102 is saying something about a low circuit input...how is that corrected?

The P0101 says MAF or VAF A CKT Range/Perf. Lost here, is that simple to correct or is something amiss in the way I re-installed the new MAFS?

P0452 states EVAP Emission Control System Pres Sensor Low: I am totally at a lost on this one here. Is this referring to some kind of sensor that is not picking up a true reading on EVAP Emissions? (just guessing on the words displayed)

If I could just get some kind of help on those 3 for now, it would be greatly appreciated. I do not want to put this vehicle back on the road for it to break down again somewhere along the line due to non-maintenance on my part.

I hope I posted this so that it can be understood. Very, very, new at this stuff, but it appears to be catching my interest as I do things to this vehicle.

Thanks!

 

All these codes are explained in the Diagnostic Trouble Codes (DTCs) section.

 

P0101 - Mass Air Flow System Performance
P0102 - Mass Air Flow Sensor Circuit Low Frequency
I would try cleaning the MAF sensor as a first step. From there, you really should run down through the diagnostic steps before plunking down the coin for a new MAF.

P030x - Random/Multiple Cylinder Misfire Detected
This code is likely resulting from the MAF codes so I wouldn't worry about this just yet.

P0452 - Evaporative Emission Control System Pressure Sensor Low Input
You may have forgotten to connect something back at the tank or possibly broken something during the fuel pump replacement. I would suggest that you go back over all of your work back there.

 

Thank you for your replies. You are correct, in my haste to re-assemble the tank, I may have forgotten or overlooked something. I thought I re-wired the sensor correctly, and what apparently was the Fuel Pressure Sensor, I did not do anything do other than re-connect it to the new fuel pump. The new fuel pumps come with an alternative sensor which is the pump sensor that pumps the fuel...correct? That is the one that I re-wired.

I will go back over, drop that tank again, (I don't care about the labor, just want it to work RIGHT!), check and make sure all connections and lines are correct and tight. I will do the same with the MAF sensor. I am kind of pumped up about fixing this vehicle.

swartlkk, I got your reply to each code I posted and have printed them off. Thanks for your help. I will work a lot more confident this time rather than guessing "this looks like it fits there"...