Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner
1 - 12 of 12 Posts

·
Registered
2006 chevy trailblazer_ls
Joined
·
206 Posts
Discussion Starter · #1 ·
is there any difference in erasing a code if i have reader, or disconnecting the negative battery terminal for period of time. I have a code po171 after diy cai deciding if the computer needs to relearn my system so it doesn't keep coming up or is still unresolved problem.
 

·
Premium Member
2007 chevy trailblazer_ls
Joined
·
1,422 Posts
Did you do anything to correct the issue? In this case if while you were doing the cai and did'nt have the battery disconnected you might be best with disconnecting the battery. Almost all other times I would recommend fixing the issue and clearing the codes so your pcm retains its stored memory.:m2:
 

·
Banned
2004 gmc
Joined
·
26,181 Posts
Disconnecting the battery doesn't erase many (if any) codes that could cause you to fail an emission test. They wouldn't allow such an easy way to get around the test. Most codes will shut off the light after 3-5 successful drive cycles (start cold, warm up, drive around for a while, then stop for a while), AFTER you cure the fault. But I'm not familiar with the most reliable way to troubleshoot a P0171 faule, which could be O2 sensor, a vacuum leak, or other things you might not have even touched with your CAI.

Is your throttle body clean, just for general principles?
 

·
Registered
2006 chevy trailblazer_ls
Joined
·
206 Posts
Discussion Starter · #5 ·
yea i have did some things to try to solve problem, my guess was a vacuum leak so reinforced my seals, and gasket with my MAF. Im getting new filter next week planning on cleaning the throttle body when i install it, should get maf cleaner too and do it, maybe it will solve the problem. thanks for the input
 

·
Registered
2009 chevy
Joined
·
6,431 Posts
My recommendation (for what it's worth), is to use a code reader.

With all of the problems people are having with HVAC actuator getting knocked out of sync, these days I only disconnect the battery when it is absolutely necessary.

You also run the risk of erasing all learned parameters within the PCM. With these parms back to factory specs, the idle and mileage may be off.
 

·
Banned
2003 gmc envoy_slt
Joined
·
7,190 Posts
My recommendation (for what it's worth), is to use a code reader.

With all of the problems people are having with HVAC actuator getting knocked out of sync, these days I only disconnect the battery when it is absolutely necessary.

You also run the risk of erasing all learned parameters within the PCM. With these parms back to factory specs, the idle and mileage may be off.
That brings up a question I've had for a while now. Why can't we just remove the #10 and #28 fuses instead of disconnecting the battery? It would be easier and shouldn't mess up the radio, HVAC, etc. Unless I'm missing something else.
 

·
Registered
2003 chevy trailblazer_ls
Joined
·
1,236 Posts
My recommendation (for what it's worth), is to use a code reader.

With all of the problems people are having with HVAC actuator getting knocked out of sync, these days I only disconnect the battery when it is absolutely necessary.

You also run the risk of erasing all learned parameters within the PCM. With these parms back to factory specs, the idle and mileage may be off.
Ding, ding, ding, ding...

Winner answer!

It takes a number of drive routines to relearn all the parameters that the PCM tracks and modifies for your particular engine and driving conditions. Erasing all of that is a real waste of time and performance. Last time I did, it took about 2 full tanks of fuel before the thing started running right again. First tank, mileage dropped from my customary 21-22 to about 16. Second tank it returned to 19. Third tank it was a rocket again (PCM tune, other mods) and economy was back better than ever.

Clear the codes with a scanner.

Even one of the cheapy code-reader scanners will clear codes. Better still is a Snap On or other high end unit. Snap On Heritage (MT2500) scanners that can read REAL TIME engine management and do multiple tests, operate all electronic equipment, ABS, transmission solenoids, etc., are now selling used for about $600. Let me know if you want one -- I have one for sale so I can move up to a Solus Pro.
 

·
Registered
2009 chevy
Joined
·
6,431 Posts
That brings up a question I've had for a while now. Why can't we just remove the #10 and #28 fuses instead of disconnecting the battery? It would be easier and shouldn't mess up the radio, HVAC, etc. Unless I'm missing something else.
I did not look up these fuses, but if they power the PCM, then yes they should work.
And, do the job without messing up the HVAC. But, it will take the PCM back to factory specs.

glfredrick, thanks for the "Ding, ding, ding, ding..."
 
1 - 12 of 12 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top