After disconnecting my battery for ~1.5 hours (To clean my MAFS) I checked with my OBD2 scan tool & got the P1111, System Pass & sure enough, all 7 of the I/M monitors wee solid. (MIS, FUE, CCM, CAT, EVA, O25 & HTR) So, the car apparently did not need to re-run the readiness diagnostic tests b4 giving me the desired P1111 code.

I was expecting to see that some were blinking & would need to drive at various speeds for a couple days b4 getting the P1111 as has happened in the past. The rerunning of these tests has happened when I have replaced Ignition coils.

So, what am I missing? I had thought disconnecting the battery for 5-10 minutes alone would cause the car to re-run these tests. I wasn’t sure I actually needed to disconnect the battery to remove & replace MAFS but, had read that doing so forces the car to “re-learn" the, now clean, MAFS. In any event, the car runs just fine. Cleaning the MAFS seems to have improved acceleration.

So, no problem, I’m just curious re this issue.

Thanks!

 

I'm glad its running great post MAF clean! I have been thru what you are going thru a couple times in the past. There seems to be no exact science when just disconnecting the battery to reset systems. By this I mean, sometimes it will be disconnected for an hour and not reset when other times it may reset with no particular time elapsed. When you perform a hard reset (holding + and - terminals together for a brief period) it resets my systems always. As for being necessary to disconnect the battery to clean the maf? It "may" not be but when mixing combustable cleaning products with electricity it is better to be safe than sorry in my opinion and disconnect, I wouldn't want to risk frying something. Enjoy!

 

I'd have thought that was long enough but try a hard reset.

If your MAF is now different (cleaner) it'll relearn without doing a reset.

 

I did not know that. Thanks!
I'm not going to bother doing a hard reset.

So, both of you who replied think in general if you disconnect the battery for a while, when you reconnect, the car re-runs the readiness diagnostic tests.
I wonder why it didn't this time?

 

I agree with JagV8 as no need for a reset, it will relearn just fine. If it is disconnected for a long enough time to reset all the modules then it will re-run the readiness, otherwise your modules will remain "ready" like they did this time around. The hard reset will guarantee it will re-run through the readiness cycles.