Reprogram the PCM

  • 4.0L
  • 6 CYL
  • 2WD
  • 200,000 MILES
I brought it in to be smogged at a test only and they said that the PCM had nothing in its memory. The vehicle was stored for about 8 months with no battery in it. So I drove around for about 200 miles to see if it'll bring up any of the settings or codes. Now if I bring it in to a dealer and do use a flash drive? I'm not sure what they're going to use how to reprogram it. Will they test it afterwards to see if it's operating and functioning correctly and if so how would they do it?
Do you
have the same problem?
Wednesday, May 15th, 2019 AT 4:50 PM

1 Reply

Welcome to 2CarPros. There is no programming needed. What they should have said is that not all of the system tests (monitors) have completed. Basically the various computers run self tests on the various systems that control the engine. Some run all the time while others only run under very specific circumstances. Being this truck sat with no battery it cleared all of the monitors as well as any learned items like idle and shift patterns.
One catch to the testing is that some of the tests cannot run if there are others that are still incomplete.
What you need to do is find out which monitors have not completed. Then find out what the drive cycle requirements are for that monitor.
For instance a drive cycle might be to start the engine cold, then drive a certain distance at or above a given speed, then stop and let the engine idle for a time, then drive at a different speed with frequent stops. Then shut off the engine and see if the monitor ran. Some like the EVAP monitor can be a real pain as the parameters for the test are specific.

So your first step is to determine what monitors have not run. If they gave you a printout it should be listed on it. Post them and we can look up the specific drive cycles you need to attempt to set them. Also if the check engine light is on you will need to get that repaired first as it will stop the tests from running on some systems.
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Wednesday, May 15th, 2019 AT 5:31 PM

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