Restting Car Computer

[Timothy Ferguson]

I want to reset my parents Ford Ranger OBD computer. So I know I have to unplug the battery but for how long? Some people tell me 5 min should do it others tell me 30 min.

See I am replacing the air filter with a K & N. Some tell me that its ok just drop it in the computer will eventually reset itself. Is that true?

 

[T-Keith]

Some parameters reset right away, some take longer. Go 30 minutes just to be safe. The computer will relearn either way, I don't think it's necessary for an air filter change. You might want to clean the MAF though.

-T

 

[mechtech]

Take off the battery cable, and step on the brakes a few times [gets rid of residual charge is some circuits].

 

[boxcartommie22]

it was neccesary for my filter change in my lin.continental..i had k&n filter in and i changed it out just to see if i feel any diference and wow did i ever. well, i put the k&n back in and the service enginelight came on..i had to disconnect the batt. for a couple of min. and that fixed it...so form now on when i do any changes iam going to disconnect the batt.

 

[T-Keith]

There are circuits in some vehicles that cannot be cleared that way, hence the wait period.

-T

 

[Timothy Ferguson]

takeing off the negative when replacing any parts is sufficiaent enough correct. You don't have to disconect the whole battery right?

 

[97tbird]

Find the high-current fuse box under the hood. find the fuse for the PCM (should be a chart in the manual showing which fuse is for what); pull that fuse, try to start car (won't start), put the fuse back in. PCM cleared.

(on ,my 4.6L T-bird it's fuse# 15)

 

[Market525]

Tim,
You stated in your EGR post that a neighbor had an OBDII reader. This same tool usually has the ability to "clear codes" on the car's computer.... just another step after he read the codes.

I'm not so sure the "unhook the battery" method is going to work on your truck.

Good luck,
Steve

 

[T-Keith]

You only have to break the circuit, negitive cable is enough. "clearing the codes" is different then resetting the computer. There are recorded values that can be cleared by disconnecting the power for a period of time and not by most code readers.

-T

 

[Gary Allan]

Yes, long term adaptive cells are typically not cleared with resetting of the PCM. Short term adaptives may be. It's the same with your VIN and odometer reading. Normal readers and unhooking the battery doesn't wipe them typically.