OP
Did not pass NYS inspection
- Thread starter JoePal
- Start date
Interesting! Thanks for chiming in. I think I'll have to do the TSB on mine and experiment some time (not soon - I'm just about to start my build, and I think the LJ will be on my lift for months...) I never did the TSB fix because we don't have emissions testing in my county (though if I lived 1.5 miles south, I'd be in a county that does - that's the craziness of government regulations). Also, our legislature recently did away with mechanical inspections starting next year, so I'll be free at last, free at last, free at last!
Mine had the O2 and Evap monitors not clearing for many months. After the TSB mod, the O2 monitor cleared immediately on starting. But the Evap monitor needed a short drive around the neighborhood before it cleared.
I checked an older and newer version of the TSB, and neither mentioned Evap. But apparently, Evap gets cleared by this mod, too.
Thanks for the feedback. I’m planning on replacing the radio so will be disconnecting the battery and figure will do the TSB at that time.
can’t thank everyone enough for the excellent support on this site.
I did a little reading up on this issue this afternoon. I think the Evap System Monitor, which is run all the time (not just once) won't run if there are any pending or permanent DTCs set, so that may be how it is affected (indirectly).
I've also learned that the TSB mod is pretty simple in what it does. Originally, the factory powered the positive side of the Automatic Shutdown (ASD) relay's coil via the Run and Start positions (so that the coil can only change the state of the relay if the key is in Run or Start). Then, the negative side of that coil is controlled by the PCM (it grounds it, to complete the energization, and keeps it grounded as long as the engine starts within 2 seconds and stays running).
The TSB changes the wiring so that the ASD relay coil's positive side is powered from Fuse 9 in the PDC. Fuse 9 is always hot (as long as the battery is connected), so the key position doesn't affect the ASD relay energization.
The Factory Service Manual (FSM) says that the O2 Sensor Heater Monitor processes some data when the PCM is powered down (after the ignition key moves to the off position, but before the PCM goes to sleep). I haven't been able to figure out why (there's conflicting information in the FSM), but apparently, those two sensor's heaters need to keep their positive side energized beyond the key off time. That is what the TSB mod does - it keeps them powered all the time. It must have something to do with how that data is collected right up until power down. If the heater power is lost, the processing never completes, and the monitor is never "Ready."
Interesting!
The TSB changes the wiring so that the ASD relay coil's positive side is powered from Fuse 9 in the PDC. Fuse 9 is always hot (as long as the battery is connected), so the key position doesn't affect the ASD relay energization.
The Factory Service Manual (FSM) says that the O2 Sensor Heater Monitor processes some data when the PCM is powered down (after the ignition key moves to the off position, but before the PCM goes to sleep). I haven't been able to figure out why (there's conflicting information in the FSM), but apparently, those two sensor's heaters need to keep their positive side energized beyond the key off time. That is what the TSB mod does - it keeps them powered all the time. It must have something to do with how that data is collected right up until power down. If the heater power is lost, the processing never completes, and the monitor is never "Ready."
Interesting!