How do you reset diagnostic codes?

[TheJMan19]

Some code readers have the ability to clear DTCs. You can also disconnect the negative battery cable from the battery for about 15 minutes, reinstall it, and the code should be cleared.

Is your Cherokee OBD-I or OBD-II? I had a 1993 Explorer (OBD-I) and whenever the computer sensed that whatever was causing the code was back within acceptable range, the light went off.

However, on my 2000 Mountaineer, I accidentally left the mass airflow sensor unplugged after putting in a new air filter, which triggered a CEL. When I plugged it back in, the light didn't go off. It takes a few long drive cycles for the computer to find that the sensor is back in range.

 

[MarkC]

Mine's a 96, I think that makes it OBD-II. I'll check the manual to verify.
I just get a 12 code, which I think means recently disconnected battery, which is true, since I recently replaced it.

 

[heyheylbj]

Go to autozone. If you hand them your driver's license and a credit card as a security deposit to make sure you don't walk with the thing, they give you a free OBD-II scanner that has the ability to clear faults.

The one at my local one also was easy to read, meaning it spat out trouble codes in plain english rather than "Error P304$%"

 

[MarkC]

On my Cherokee, I know how to access them, but is there an easy way to clear them?

 

[GMBoy]

I highly recommend against disconnecting the battery cable to clear codes. Especially with OBD2 since the code won't clear that way anyhow, use the scan tool. By disconnecting the battery the car than has to relearn all the parameters that it has learned for thousands of miles - thats why it'll run rough for a while after doing this. All 1996 and later (and limited 1994/95's) are OBD-II.

 

[Gary Allan]

Not so GM. The codes on the DC PCM do clear with the bat disconnect ..and the long term adaptives are retained. This may be different on GM electronics ..but this is how the numb dumb DC PCM works. It is a simple speed density system and only increments or decrements the lean and rich conditions encountered during open loop operations.

Code 12 (dash flash) shouldn't set a CEL condition anyway. This could only be read with the key ON-OFF-ON-OFF-ON method of reading the codes (there is no such OBDII code as "12"). This code is present on just about every DC vehicle OBDI or OBDII when this method is used. My Caravan has not had the battery disconnected in 2 years ..yet shows this code every time I set up the display.

If you're trying to reset this code ..or find its cause ..you've got a lifetime of work ahead of you and will never solve your problem. You don't have one.