Best way to clear a code?

[MacManInfi]

97 ViperGTS. I've got a Creader from Harbor Freight. The instructions say to let the code flash four times, and then it will clear. I can leave that thing in there for five minutes and it'll only flash three times, launch again, then flash three more times, repeat. Doesn't ever flash four times and it doesn't clear the code.

I'm pretty sure an O2 sensor went out today and just before I got home with the new O2's it threw a check engine light. Code reader says 175 (rich). I replaced the O2's and the car is running great again, but still have the check engine light.

 

[PhoenixGTS]

Unplug the three big connectors into the PCM for awhile, or if you do not want to pull the PCM cover pull the appropriate fuse for awhile.

 

[MacManInfi]

Thanks. I unplugged the battery prior to your post. Should have the same effect, yes?

 

[RAYSIR]

From what I've seen and heard over the years is that the codes can only be cleared from a scan tool that is designed to "clear codes". This is on all OBD2 1996 and newer cars and trucks. Have never seen or heard of code clear without one or replacing computer. On older pre 96 we used to pull fuses, unhook battery, disconnect computer but not on OBD2. Shucks has scanners and they don't charge much to check codes. See if they will also clear them?? HEH, MacMnan stop by my shop and I'll read em and clear em for you for FREE!!!

 

[Supercharged Vipermad]

HEH, MacMnan stop by my shop and I'll read em and clear em for you for FREE!!!

FUNNY STUFF!!!

 

[Steve 00RT/10]

I have a OBDII reader/eraser and a battery shut off switch. Strange as it may seem, the only way I've found to make the car go completely brain dead is to turn the battery switch off, disconnect the PCM plugs and disconnect the ground below the PCM for 15 minutes or so. You can expedite the drain process with a jumper wire from the positive post (batt disconnected) to ground. You might want to reset the TPS after re-energizing the system by turning the key to on and moving the throttle linkage through the full range one time.

Steve

...some say you have to actually disconnect the negative right at the battery to achieve a 100% dead brain.

 

[DAMN YANKEE]

Two simple solutions, both mentioned.

Remove battery cable for a minute or two.

Unplug the PCM cables for a minuite or two.

But the real solution is to buy the incredibly useful and cheap OBD2 reader/clearer.

http://www.roeracing.com/ProductCart/pc/viewPrd.asp?idcategory=8&idproduct=76

from here and elsewhere. Most places will charge this price for a single read.

 

[GTSnake]

Doesn't the code clear it self after a number of key offs? I thought after like 3-5 key offs it clears itself.

 

[Steve 00RT/10]

But the real solution is to buy the incredibly useful and cheap OBD2 reader/clearer.

Yes, the readers will clear any codes. however, they will not erase other bad things the computer may have stored, but don't set a light. For example, idle hang / idle drop off problems with our superchargers. I have one car with a little hang problem and one with a drop off problem. A slight blip on the throttle coming to a stop fixes the drop off problem (otherwise it will occasionally stall before before finding itself back to normal). There are no codes set, but if I do all that I listed above(disconnecting the ground is a must), the car will run perfect, with no drop off, for a couple of start cycles........then it starts again. It's a quirky little thing and not a big deal to me anymore. A very small tradeoff for the big smile I get every time I put my foot in it.

As for how long you have to wait when disconnecting the PCM/Battery......You'd be surprised how long there is some residual built up voltage in there. It's longer than a minute or two. That's why I usually drain it off completely by putting a jumper with clips on it from the positive post to ground. Much quicker.

Steve

 

[luc]

I don't know if you realize that MacManInfi has exactly the same model from Harborfreight, but without the Viper Tax ( $40 instead of $54)

Luc 00GTS


But the real solution is to buy the incredibly useful and cheap OBD2 reader/clearer.

http://www.roeracing.com/ProductCart/pc/viewPrd.asp?idcategory=8&idproduct=76

 

[MacManInfi]

Yup, I have exactly the same reader, but following the instructions, I couldn't get it to clear. Left the negative off the battery last night. All is well this morning.