ALDL
 

OK, so the Service Engine Soon light comes on (after I had the fuel pump replaced), and, after checking the gas cap to make sure it's good, I wait a few days for the light to go off. It is still on. So I figure Option 2 would be the O2 Sensors, since that always set off the light on my S10s. So, to make sure, I go out an buy a code reader, and hook it up to the ALDL under the dash. Nothing, nada, ziltch. No info whatsoever. Its like the code reader wasn't working. To make sure I didn't get a bum reader, I hook it up to my Trailblazer. Reader works fine. Go back to the Blazer, nothing. Anybody got any ideas?

RE: ALDL
 

Check the CIG fuse. And don't jump to conclusions on why the CEL is on before getting the codes. It is possible that the seal at the top of the tank is bad...

RE: ALDL
 

So if the CIG fuse is out, the ALDL won't work? The Cig fuse is burnt out, I know that for sure.

RE: ALDL
 

Yes, the power feed for the DLC (ALDL) is on the same circuit as the cigarette lighter.

Please put your vehicle information into your sig and attach it to your posts. Makes it easier on those of us trying to help. Thanks!

RE: ALDL
 

Well, I walked out and looked to see if I have any spare fuses. Of course, I don't! I'll pick some up tomorrow, swap out the bad one, and see if the reader says what I think it's going to say.

Thanks for the help!

RE: ALDL
 

Ok, so I pulled two codes: P0446 and P0452. The book says that P0446 says that the EVAP canister vent is blocked, and the EVAP fuel tank pressure sensor has low input. What do these mean in English? I just had someone replace the fuel pump, is this related to that?

RE: ALDL
 

P0446 Explained
P0452 Explained

The work that was done on your fuel system may not have been completed properly. The sending unit to tank seal would be the first thing I would check. If you JUST had your fuel pump replaced (within the last week or so), I would take it back to the shop that did the work and tell them that this problem didn't exist prior to the work that they did.

RE: ALDL
 

Wow, I now feel retarded. Somewhere in that mumbo-jumbo, I saw that an accurate indication of fuel level was needed to pass the DTC. Would an inaccurate fuel level cause bad readings? Reason I am asking, when I got the truck back, the gauge said 1/4 tank. I took it to the gas station and after 3 gallons, the pump shut off. It was full, but the gauge still said 1/4 tank. After driving about 100 miles, the gauge finally moved, now indication a little above a 1/2 tank. Would this have anything to do with it? And please, PLEASE, never hit me with a schematic and narrative like that again. I would rather wear a bacon suit in Iraq during Rammadan than endure that again!

RE: ALDL
 

Sorry to even bother.

RE: ALDL
 

:DI can appreciate that feeling, Chris. I neverhave beengood at reading schematics. But, when Kyle answers a post he tries to give the best and most complete answer that he can, which is a very good thing. No such thing as too much information.
Though I do remember once when he teased me for being a bit verbose... ;)