clear codes

[Toasty]

how long does the pos/neg need to be disconected to clear trouble codes? hour? two? three?

[Incomudrox]

Or...you can pull the PCM fuse and put it back. But to answer your question 30min.

[GeddyLee]

If you had my LS1m Toasty, you could clear that way

LOL sorry brother, it was to easy to pass up

I agree with the above, 30 minutes to an hour is what I have done before to clear codes. Just be aware of what the code might be, you dont wanna go blowing anything up ya know

[IndeedSS]

Can all codes be cleared by disconnecting the battery?

[archemedes]

I have had a pcm in my garage with a missfire code for 2 years now, plugged it in, and the code is still there

[SyntheticShield]

I have had a pcm in my garage with a missfire code for 2 years now, plugged it in, and the code is still there

Are you kidding? What in the world is the PCM using to power memory storage for that long? How is it doing that?

[IndeedSS]

must be storing that in the non-volatile memory. This is why I ask about clode clealring as I've had a battery disconnected for days and the code that was there stayed.

[archemedes]

must be storing that in the non-volatile memory. This is why I ask about clode clealring as I've had a battery disconnected for days and the code that was there stayed.

that's what I think also, it baffled me when I saw it

[SyntheticShield]

Well crap, I had no idea. That sucks. So now how is anyone to clear the code if they do not have access to a scan tool or someone that does?

[Toasty]

just to add to the info, here's the things that i tried to clear out the P0171 code:

all of these did not work---

disconnect postive and negative... off 1.5 hours
disconnect only positive, less than 10 min.
disconnect positive, unplug PCM fuse.

today, i ran the car back over to advance auto, had them run the codes again. still the P0171 code, but it's a stored code, not a pending (current) code anymore. I think PENDING codes may clear with battery disconnect, not stored. So i asked him to clear it out. (this is just between you and me he says, lol) the code hasnt come back, so appears problem fixed.

[Toasty]

If you had my LS1m Toasty, you could clear that way

LOL sorry brother, it was to easy to pass up

I agree with the above, 30 minutes to an hour is what I have done before to clear codes. Just be aware of what the code might be, you dont wanna go blowing anything up ya know

hahahaha yer sooo funny

my LS1m parts are on the way. should be a fun assembly project

perhaps i even will save $$ vs what you paid :P

[GeddyLee]

just to add to the info, here's the things that i tried to clear out the P0171 code:

all of these did not work---

disconnect postive and negative... off 1.5 hours
disconnect only positive, less than 10 min.
disconnect positive, unplug PCM fuse.

today, i ran the car back over to advance auto, had them run the codes again. still the P0171 code, but it's a stored code, not a pending (current) code anymore. I think PENDING codes may clear with battery disconnect, not stored. So i asked him to clear it out. (this is just between you and me he says, lol) the code hasnt come back, so appears problem fixed.

I had that same code before. It read that bank 1 sensor was the problem. IE an O2 Sensor. At least that is what the Autozone computer said. I thought maybe I hit the rear sensor at the top of the DP when I was changing out factory spark plug wires.

So I went back in and disconnected the battery the following the morning and left it offline for almost 2 hours and came back and rechecked all connections, even the O2 Sensor and then reconnected the Power to the battery and the code was cleared. Hadnt come back since.

Glitch or not? Not sure cause if it was truly a bad sensor it would have kept coming back.

[GeddyLee]

hahahaha yer sooo funny

my LS1m parts are on the way. should be a fun assembly project

perhaps i even will save $$ vs what you paid :P

You know I had to poke a little jab in there my friend

Good luck on the project. If you have any questions or need to take any photos of mine for ya? Please let me know. I will be more than glad to help ya with as best I can.

[SyntheticShield]

That is correct, stored codes I do believe will not clear. Active ones will. However, pending codes dont trip the SES light.

[Toasty]

That is correct, stored codes I do believe will not clear. Active ones will. However, pending codes dont trip the SES light.

???? active=pending my friend... pending doesnt mean what you think it means


there's stored codes, and pending codes. pending codes are active/current.

stored codes are ones that were active/pending, but are just stored in memory now.

[Toasty]

I had that same code before. It read that bank 1 sensor was the problem. IE an O2 Sensor. At least that is what the Autozone computer said. I thought maybe I hit the rear sensor at the top of the DP when I was changing out factory spark plug wires.

So I went back in and disconnected the battery the following the morning and left it offline for almost 2 hours and came back and rechecked all connections, even the O2 Sensor and then reconnected the Power to the battery and the code was cleared. Hadnt come back since.

Glitch or not? Not sure cause if it was truly a bad sensor it would have kept coming back.

the P0171 is NOT an O2 code. i know it seems like it could be, but it's not, at least according to the trouble code diagnostics from GM that i posted up over on the how-to section. anywhoo, mine was a vac leak, allowing unmetered air into the system after the MAF.

You know I had to poke a little jab in there my friend

Good luck on the project. If you have any questions or need to take any photos of mine for ya? Please let me know. I will be more than glad to help ya with as best I can.

Thanks for the help... Mark is gonna assemble most of it i think, i may need to sacrifice a usb cable to put it together, but that should be about it.
but if i get stuck, i'll give ya a holler.

[MTXGTP]

disconnecting the battery will not work the last year of vehicle that will work on is is 97' so the only other way to erase the code is with a code reader.

[SyntheticShield]

How in the world is a 'pending' code an active code. That defies the very definition of the word.

[Toasty]

How in the world is a 'pending' code an active code. That defies the very definition of the word.

if pending code meant what you'd think of 'pending' ... our cars would be psychic!

[PitchBlackSS]

you dont need to spend a fortune for a code reader either, got mine for under $50. I didnt want to leave the laptop and PowrTuner in the car, so this is great for the glove box. Home Depot and Lowes carry cheaper ones.

BTW, mines an Actron CP9125, very basic reader, just displays the code, you need to look it up in a book. I got mine for the period after the cat install and before the PCM tune.