[Solved] Emissions readiness test for catalyst not completing after 600 miles | Ford Explorer Forums

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[Solved] Emissions readiness test for catalyst not completing after 600 miles

Post number 2 has been selected as best answered.

tinkerford

New Member
Joined
April 26, 2025
Messages
5
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City, State
GV, CA
Year, Model & Trim Level
1997 XLT 4.0L V6 SOHC
1997 Explorer V6 SOHC XLT 5 door 4WD Gen2 (1995-2001), that has been in the family for nearly 30 years, constantly maintained, and never had any issue until now.
I'm at my wits end as I have been trying for over two weeks, with 600 miles driven, to get the Emissions Readiness Test (ERT) for the Catalyst to complete, so that I can take it for a CA Smog test. Previously when battery was disconnected, or ODBII was reset, all the ERT completed within 100 miles with simple regular driving (in same location I am now).

My problem recently started because one of the upstream, pre cat, O2 sensors died. I replaced it and cleared the ODBII codes.

I have ForScan with Vgate vLinker FS USB connection which shows me engine readings and emissions readiness. The replaced O2 sensor is reading the same as the one on the other side so I know it is good. There are no longer any ODBII error codes. O2 Sensor test completed.

In fact all Emissions Readiness Test have completed except for Catalyst.

6 months ago I replaced Battery (6 yrs old) and Alternator as it was only charging at 13.5v. It is now charging at 13.8-14.4v when idling. Car sat for 4 months with battery disconnected as I was away from home. Battery was 12.7v when reconnected, turns over fast, and starts first time within a second. Battery test result shows 98% SOH when using CCA.

ABS light blinks code 12 (low battery): can that affect anything?

I found multiple conflicting Ford drive cycle instructions for the Catalyst readiness test and have followed:
  1. Cold Start, Fuel level between 15% and 75%.
  2. Turn key on but do not crank engine. Turn key off, then on, and start engine.
  3. Idle in drive for 2 minutes.
  4. Always slowly accelerate. Never press accelerator pedal more that 25%.
  5. Drive at 45 mph until coolant temperature is at least 170F.
  6. Drive at constant speed of 20 mph for at least 90 seconds then stop and idle for at least 30 seconds. Repeat same at 25mph, 30mph, 35mph, 40mph.
  7. Repeat step 6.
  8. Maintain a steady speed between 45-60mph for 5 minutes.
  9. Stop the vehicle and idle for 2 minutes.
  10. Repeat all steps at least 5 times.
I have repeated the above steps at least 15 times in the last week.

Coolant level good and temperature is dead center when warmed up and stays there constantly. Idle varies by about 50 rpm. Voltage steady just below middle (where it has always been when alternator was working).

Questions:
  1. I can't find any definitive Ford Explorer Gen 2 Drive Cycle instructions. Can anyone provide more detailed instructions? Does anyone have access to a Service Manual that details the steps?
  2. I live in the foothills, with lots of ups & downs, so it is difficult to maintain constant speed without letting off accelerator or braking. Could this be a problem?
  3. EVAP test took a while and I think it only completed because I maintained partial throttle (PT mode) whilst keeping speed at 45-55mph by simultaeously pressing accelerator and brake peddle to maintain required readings.
  4. Anyone see something I have done wrong?
 



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1997 Explorer V6 SOHC XLT 5 door 4WD Gen2 (1995-2001), that has been in the family for nearly 30 years, constantly maintained, and never had any issue until now.
I'm at my wits end as I have been trying for over two weeks, with 600 miles driven, to get the Emissions Readiness Test (ERT) for the Catalyst to complete, so that I can take it for a CA Smog test. Previously when battery was disconnected, or ODBII was reset, all the ERT completed within 100 miles with simple regular driving (in same location I am now).

My problem recently started because one of the upstream, pre cat, O2 sensors died. I replaced it and cleared the ODBII codes.

I have ForScan with Vgate vLinker FS USB connection which shows me engine readings and emissions readiness. The replaced O2 sensor is reading the same as the one on the other side so I know it is good. There are no longer any ODBII error codes. O2 Sensor test completed.

In fact all Emissions Readiness Test have completed except for Catalyst.

6 months ago I replaced Battery (6 yrs old) and Alternator as it was only charging at 13.5v. It is now charging at 13.8-14.4v when idling. Car sat for 4 months with battery disconnected as I was away from home. Battery was 12.7v when reconnected, turns over fast, and starts first time within a second. Battery test result shows 98% SOH when using CCA.

ABS light blinks code 12 (low battery): can that affect anything?

I found multiple conflicting Ford drive cycle instructions for the Catalyst readiness test and have followed:
  1. Cold Start, Fuel level between 15% and 75%.
  2. Turn key on but do not crank engine. Turn key off, then on, and start engine.
  3. Idle in drive for 2 minutes.
  4. Always slowly accelerate. Never press accelerator pedal more that 25%.
  5. Drive at 45 mph until coolant temperature is at least 170F.
  6. Drive at constant speed of 20 mph for at least 90 seconds then stop and idle for at least 30 seconds. Repeat same at 25mph, 30mph, 35mph, 40mph.
  7. Repeat step 6.
  8. Maintain a steady speed between 45-60mph for 5 minutes.
  9. Stop the vehicle and idle for 2 minutes.
  10. Repeat all steps at least 5 times.
I have repeated the above steps at least 15 times in the last week.

Coolant level good and temperature is dead center when warmed up and stays there constantly. Idle varies by about 50 rpm. Voltage steady just below middle (where it has always been when alternator was working).

Questions:
  1. I can't find any definitive Ford Explorer Gen 2 Drive Cycle instructions. Can anyone provide more detailed instructions? Does anyone have access to a Service Manual that details the steps?
  2. I live in the foothills, with lots of ups & downs, so it is difficult to maintain constant speed without letting off accelerator or braking. Could this be a problem?
  3. EVAP test took a while and I think it only completed because I maintained partial throttle (PT mode) whilst keeping speed at 45-55mph by simultaeously pressing accelerator and brake peddle to maintain required readings.
  4. Anyone see something I have done wrong?

Some potentially useful info >>> Catalyst Monitor never ready -- but I've done the Drive Cycle


California rules:
Note that a car can pass with some incomplete monitors…a maximum of one on 1999 and earlier cars, and only one (The Evaporative System monitor) on model year 2000 and later gasoline powered automobiles.
 






1997 Explorer V6 SOHC XLT 5 door 4WD Gen2 (1995-2001), that has been in the family for nearly 30 years, constantly maintained, and never had any issue until now.
I'm at my wits end as I have been trying for over two weeks, with 600 miles driven, to get the Emissions Readiness Test (ERT) for the Catalyst to complete, so that I can take it for a CA Smog test. Previously when battery was disconnected, or ODBII was reset, all the ERT completed within 100 miles with simple regular driving (in same location I am now).

My problem recently started because one of the upstream, pre cat, O2 sensors died. I replaced it and cleared the ODBII codes.

I have ForScan with Vgate vLinker FS USB connection which shows me engine readings and emissions readiness. The replaced O2 sensor is reading the same as the one on the other side so I know it is good. There are no longer any ODBII error codes. O2 Sensor test completed.

In fact all Emissions Readiness Test have completed except for Catalyst.

6 months ago I replaced Battery (6 yrs old) and Alternator as it was only charging at 13.5v. It is now charging at 13.8-14.4v when idling. Car sat for 4 months with battery disconnected as I was away from home. Battery was 12.7v when reconnected, turns over fast, and starts first time within a second. Battery test result shows 98% SOH when using CCA.

ABS light blinks code 12 (low battery): can that affect anything?

I found multiple conflicting Ford drive cycle instructions for the Catalyst readiness test and have followed:
  1. Cold Start, Fuel level between 15% and 75%.
  2. Turn key on but do not crank engine. Turn key off, then on, and start engine.
  3. Idle in drive for 2 minutes.
  4. Always slowly accelerate. Never press accelerator pedal more that 25%.
  5. Drive at 45 mph until coolant temperature is at least 170F.
  6. Drive at constant speed of 20 mph for at least 90 seconds then stop and idle for at least 30 seconds. Repeat same at 25mph, 30mph, 35mph, 40mph.
  7. Repeat step 6.
  8. Maintain a steady speed between 45-60mph for 5 minutes.
  9. Stop the vehicle and idle for 2 minutes.
  10. Repeat all steps at least 5 times.
I have repeated the above steps at least 15 times in the last week.

Coolant level good and temperature is dead center when warmed up and stays there constantly. Idle varies by about 50 rpm. Voltage steady just below middle (where it has always been when alternator was working).

Questions:
  1. I can't find any definitive Ford Explorer Gen 2 Drive Cycle instructions. Can anyone provide more detailed instructions? Does anyone have access to a Service Manual that details the steps?
  2. I live in the foothills, with lots of ups & downs, so it is difficult to maintain constant speed without letting off accelerator or braking. Could this be a problem?
  3. EVAP test took a while and I think it only completed because I maintained partial throttle (PT mode) whilst keeping speed at 45-55mph by simultaeously pressing accelerator and brake peddle to maintain required readings.
  4. Anyone see something I have done wrong?

California Bureau of Automotive Repair​

1745748519515.png

 






Note that a car can pass with some incomplete monitors…a maximum of one on 1999 and earlier cars, and only one (The Evaporative System monitor) on model year 2000 and later gasoline powered automobiles.

The smog station I took it to told me all the EVAP and Catalyst tests had to be complete before they could SMOG it. Guy there also told me a story about another 1998 Explorer owner who had to get a special exemption from DMV after driving 1000 miles and still not being ready. Maybe he was blowing some smoke.

I will call around some SMOG stations quoting the CA Gov site you provided and see what they say. Will be great if they allow it.

Thanks for the info.
 






The smog station I took it to told me all the EVAP and Catalyst tests had to be complete before they could SMOG it. Guy there also told me a story about another 1998 Explorer owner who had to get a special exemption from DMV after driving 1000 miles and still not being ready. Maybe he was blowing some smoke.

I will call around some SMOG stations quoting the CA Gov site you provided and see what they say. Will be great if they allow it.

Thanks for the info.
Looks like they may be planning or could have recently changed it to be more restrictive, which would tie in with what you were told by the one shop...like literally just months ago

Link to draft proposal striking the previous more lenient terms


Link to proposed new language

 






Looks like they may be planning or could have recently changed it to be more restrictive, which would tie in with what you were told by the one shop...like literally just months ago
You were right the first time. Called 3 local CA Smog stations and they all said a 1997 car can have one Emissions Test not completed and will still pass SMOG.

Took the Explorer in, and she passed SMOG, with lower than average results, as she has always done.

Thank you so much for letting me know about this. I spent at least $100 on gas, and many hours of useless driving, trying to get the Catalyst test to be ready, when I did not need to do so. Could have easily spent/wasted twice more trying to get the test ready for no reason.
 






You were right the first time. Called 3 local CA Smog stations and they all said a 1997 car can have one Emissions Test not completed and will still pass SMOG.

Took the Explorer in, and she passed SMOG, with lower than average results, as she has always done.

Thank you so much for letting me know about this. I spent at least $100 on gas, and many hours of useless driving, trying to get the Catalyst test to be ready, when I did not need to do so. Could have easily spent/wasted twice more trying to get the test ready for no reason.
Emissions nonsense like what you described really sets me off, so I feel your pain, and I'm also happy I was able to help. :D

My only caution going forward is be very cognizant about ever disconnecting the battery...like no battery related stuff in the months before an inspection. Every time the battery gets disco'd, you're back to square one or worse with the readiness nonsense. In addition, to get longer life out of the battery and assuming it's not too much of a hassle I highly recommend installing a trickle changer under the hood and leaving the Explorer plugged into it when not in use. I use these on everything I own. Mount under the hood near the battery using Velcro or hot glue (I use hot glue) then run an extension cord from the charger out the front of the grille for easy plug-in/un-plug. They extend battery life from the avg 7 years to 10+, also the vehicle will always have a strong charge. The Schumacher SC1300 unit below is my favorite, although a little spendy these days -- but the sub $10 Chinesium units on Ebay and Amazon can work just as well.

1745919575193.png


 






Emissions nonsense like what you described really sets me off, so I feel your pain, and I'm also happy I was able to help. :D

The guy at the first smog station was young and just took over the place. The other places all knew. I have owned this car for 20+ years and did not know because I never had a problem with it before.

I highly recommend installing a trickle changer under the hood and leaving the Explorer plugged into it when not in use.

Yes, I have already been thinking about a solar trickle charger. Another thing I need to fix on the car is the ABS electrical module (inside car). Turns out it has a battery and if it drops too low then it gets permanently bricked and needs to be replaced. The ABS light is flashing code 12. Caused by leaving the car disconnected.
 






To get my catalyst monitors set I Drive a short loop around my local neighbor hoods. Ill start the car let it hit OP temp and then just go through 3 stop and go stop signs. Drive 50mph on the road for about 1.5 miles, hit a stop light, another 1 mile, stop, and then a straight shot for about 2.5Miles and by the end of that 2.5mile stretch the scan tool shows complete. and then I take a small loop road back into my neighborhood. seems to get every system other than evap ready.

Confused as to why yours doesn't want to complete as it seems to not take very long at all for me.
 






The earlier trucks were different 95-97 can be tricky
If it has not completed them by 600 miles I would try a hard reset and try again

It should not take more then 10-15 drive cycles maximum after all codes are cleared
 






Thanks amj441 & 410Fortune, My issue has been solved as it turns out the car could pass smog with one emission test being not ready. I have marked the thread solved.

I have no idea why it was taking so long as previously it took less than 100 miles.
 






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