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Safe Computer Reset

100K views 14 replies 6 participants last post by  James L 
#1 · (Edited by Moderator)
Hey guys, I'm looking for a safe way to reset the computer ECU in my DII. I installed a new MAF and it keeps throwing engine check lights for rich/lean conditions.

This problem happened last summer when I replaced my MAF with a used unit. Resetting (with the test book) solved this. I believe the problem is what the computer remembers of the user settings. Since it learned from the bad MAF, it has a bad interpretation of what an A/F map should look like.

I just want to make sure unhooking the battery and flipping the headlight switch overnight is the way to fly.
 
#2 ·
Tell me you are kidding when you mentioned unhooking the battery and flipping the head light switch, that is the lamest thing I think I have ever heard.
Why not do it the one and only way you can, scan and clear the codes, and assuming your new, used MAF is good, then you will be done with it.
 
#3 ·
I cleared the codes, Im just tired of clearing them on a daily basis because of what the computer has learned off the old MAF. When you reset the computer it resets what the computer has learned to structure an A/F map. Unhooking the battery is just one way of doing this. You can also reset it at the dealer using test book for a nominal fee. I replaced my MAF with a brand new genuine unit so now I have to reset what the computer has structured off the old crappy MAF.

We used to do this on imports all the time when we changed something small so the computer could relearn the timing curve based on the type of fuel used.
 
#4 ·
you can leave the battery disconnected for a week and nothing will change, ecu not's gonna reset all by itself. You can clear the maf code with a generic code reader. Once reset, the engine should run fine, if not,you have other issues
 
#5 ·
I clear the code everyday with my code reader. It returns everyday after about 10 minutes. I put in the old sensor and the truck runs like ****, but no codes are thrown.

Did my little procedure earlier and put 100kms on my baby, and no codes on the new sensor.

Guess it was pointless to post because nobody knows what the heck Im on about.
 
#6 ·
To put this simply, when you kill the power to an ECU. It will remember all the fault codes that are stored into its memory.

However, it will not remember all the adjustments and such that it makes while your driving. These adjustments are made to the Air/Fuel Map and Timing maps to give the engine optimal performance based on the type of fuel, altitute and general driving style. It gets these signals from all the sensors on the engine, mainly the MAF,TPS and the O2 Sensors. If you put in a poor condition sensor that doesnt read entirely accurate. Reset the computer, the ECU doesnt know the sensor is in poor condition unless its poor enough to set off an engine check code because it varies too much from the default map embedded into the ECU. It reads off the default map and adjusts according to the information it receives from the engine. The first 10 minutes of driving or so after a reset are where it makes most of the adjustments in a large manner. Afterwards, its very very slight adjustments.


Am I making any sense to anyone?
 
#7 ·
yes and it sounds like you have another bad MAF sensor. Once the ECU gets proper input from the MAF sensor, it will adapt following several drive cycles. It's not throwing codes beacuse the ECU thinks the MAF is bad, it's throwing codes because the ECU is getting bad data from the MAF. What codes are you resetting everyday, if it's p0102 or po103 (I think, don't have rave on this machine) then it's your MAF. I went thru 2 used one's and finally on the 3rd got mine to run correctly.
 
#8 ·
So what code keep popping up and what have you done to repair the faults listed???????
 
#9 ·
I dont know the exact code numbers off hand. I know its rich and lean both banks (4 codes). The MAF is a brand spanking new geniune land rover part.

The difference in milage and driving is drastic. The truck ran like a bag of crap on the old sensor. It runs so good and smooth with this one. After I did my little reset and driving last night, I did 80kms this morning and not a problem. That and Im getting way better milage.

Should probably mention last fall I replaced all the 02 sensors. I use ONLY geniune land rover parts. Mechanically, I take excellent care of my truck. It doesnt leak a drop, and when it does, its usually fixed in 24 hours - pending parts.
 
#10 ·
Next time the codes pop up get back to us with the 4 digit numbers, there is something else going on.
 
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