Joined: Sat Nov 4th, 2017
Occupation: Process Technician
Interests: Firearms & Ammunition, Ford Rangers, electronics
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| Before I get talking, I want to say real quick that I'm aware 'rebooting' isn't technically the correct word to use for what we're going to do. I would refer to it as a 'reset', but that usually seems to carry the connotation that the firmware/software/operating system/programming/whatever has been reinstalled, and this does not go through that process.
Second of all, this is completely safe to do as long as it is done properly. You will not damage anything. I have done this procedure to both my truck and my father's truck with no ill consequences.
So, with all that out of the way, what are we doing, anyway? Some of you may have a truck that has strange tendencies. Perhaps it shifts roughly or the engine speed likes to hang at a specific RPM, what have you. This quick and simple process is something you can do for free and may solve some of the problems or behavior issues you're encountering.
But, before I tell you how to do it, I want to tell you why we're doing it. As the Ranger is driven, the PCM is watching what you're doing and it learns how you drive. The owner may not notice it, but you will when you get into the driver's seat because it's learned to him/her and not to you. As a result, this can cause what appear to be problems when in reality it's just a learned behavior. This process forces the PCM to forget it's adaptations and is taken back to the factory profile/parameters.
First off, pop the hood and locate your battery. This is on the driver's side near the front. Remove both terminals and place a thick rag over the battery's terminals to prevent the cables from slapping down onto them and reconnecting.
Tip: Now is a good time to clean those terminals and perhaps replace or install new terminal rings to prevent corrosion or other issues.
Now, take either a spare piece of wire or a small jumper with alligator clips and connect both cables together.
"Yikes! Won't that bust something?" You may ask, and the answer is, no it won't. The computer has several capacitors inside of it. Disconnecting the terminals normally does not allow them to drain, thus the computer doesn't forget anything in any short period of time. By connecting the cables together, we're discharging the capacitors and thus it loses its memory but not it's programming.
Leave it connected for a few minutes or so. The actual discharging process only takes less than five seconds, but I personally like to leave them connected while I check my oil and clean the terminals. That amount of time ensures everything is completely discharged.
After reconnecting, know that the truck will need to relearn what it has forgotten. However, you will immediately notice a difference in how it behaves. You should only have to do this once while the truck is in your possession, as then it will begin to learn to your habits.
1999 Ford Ranger XLT - 3.0 V6 4x4 - Loaded