Help! Can't pass inspection..

About a week ago I threw a CEL and it was a "large vacuum leak". Well the night before I dropped the jeep off for inspection I found the leak and fixed it. It was a hose off the intake by the way. Since my code scanner can't clear codes, I just disconnected the battery for 15 minutes to reset the computer to get rid of the CEL.

That night I dropped it off for inspection after driving <10 miles after resetting the computer and everything passed with flying colors until they hooked it up to the computer to test emissions (yes PA has emissions testing :badpc and their computer said the jeep was "not ready to be tested" which means FAIL. The only advice they gave me was to drive around and put as many miles on it as I could then come back.

Is this because I reset the computer right before taking it in or what the heck is going on?? Anyone know how many miles I need to put on?

Yes, it was caused by resetting the PCU. It's a "drive cycle" that vehicles have to go through to relearn everything. It ranges by vehicle, but it can consist of driving a 30-40 mph for X miles than 60 mph for X miles etc.

Hopefully someone can pipe in with the exact drive cycle. Also what year is yours? I assume 97-01.

Yep, 2001.

XJWOLF said:

Yes, it was caused by resetting the PCU. It's a "drive cycle" that vehicles have to go through to relearn everything. It ranges by vehicle, but it can consist of driving a 30-40 mph for X miles than 60 mph for X miles etc.

Hopefully someone can pipe in with the exact drive cycle. Also what year is yours? I assume 97-01.

Click to expand...

Whether or not this changed between 98 and 01; my FSM states that when a problem is repaired or ceases to exist the PCM cancels the code after 40 warm up cycles, but when a PCM has been reset by removing power... the PCM has to receive and store satisfactory signals from all sensors for 5 warmup cycles or 50 miles...

Necro-bump.

I'm having the same issue pretty much. My 99 has been sitting in the garage without a trickle charger on it and the battery went kaput. Finally brought it out this weekend and put a new battery in but it won't pass inspection because of not ready to test symptoms on both o2's. So 5 complete warmup cycles will do it? I've only got the 2 week window for my retry but I don't dd the thing so even getting 50 miles might be tough with my schedule.

Put the rear on jackstands, chock the front wheels, stick it in gear and catch up on your favorite TV show...

Will it work if I do that but in reverse? Wouldn't hurt to take some miles off before my dad finds out I was driving it. I was supposed to be in school anyway.

Find a scanner that can read I/M flags (OBD II). In most states with plug-in emissions pre 2000 OBD II vehicles can have up to 2 I/M flags "not ready" where 2000+ are only allowed one.
Drive it just enough to where the I/M flags toggle over and you'll be all set. Also check for pending codes. They'll sometimes fail you for them as well.

hahaha :laugh2: I haven't seen that flick in forever.

I know for a fact that reverse adds the miles just like forward does on 91 and later, not sure how RENIX jeeps with the mechanical odo handle it. The sensor in a 91 or later sends the same kind of pulse signal no matter which way it spins... 91-92 are (iirc) 8 pulse/rev VRM while I know 95 and later are 8 pulse/rev hall effect, not sure what 93/94 are. Either way, the ECU can't tell which way it's going.

Side note... this is also how you can call bullshit on a sellers claim that "the XJ was towed behind a motorhome, only drove it for around 75k, the rest of that 220k is it being towed" because the gauge cluster and ECU don't watch those signals when they're off.