2002 Dodge Grand Caravan OBD-II I/M Reset Question

Our 2002 Dodge Grand Caravan is due for NJ State Inspection this
month, and in keeping with Murphy's legacy, our "check engine" light
decided to appear a week ago. Using the key on-off sequence, the
failure code was a P0456, or small evaporative emissions control system
leak. Researching the situation, I found reports about this occurring
via a loose fitting or failed gas cap. We have been wanting a locking
gas cap anyway, so I replaced same, but neither the "check engine" nor
the P0456 failure code disappeared after several engine cycles. Not
knowing at this point as to whether the problem had been solved or
whether the PCM was taking its time resetting, I purchased an Actron
9135 scan tool and reset the P0456 failure code.

After resetting the code, four of the I/M parameters went to "NOT
READY" (CATALYST, EVAP SYS, O2 SENSOR, and HO2 SENSOR). After 50+ miles
of driving with several engine cold-hot cycles, the "check engine light
has not reappeared, and three of the above I/M parameters have gone back
to "READY", but the HO2 SENSOR parameter remains at "NOT READY".

Does anyone have any info as to how long this HO2 SENSOR code will
take to reset? I have the factory service manual, but can't find any
info there. If its going to take 30 or 40 engine cycles to reset, I'll
have to just let the car fail inspection, but would rather not go that
route if there is anything I can do to get this parameter back in line.

Thanks in advance for any help!


George

 

George, That's why you don't do a battery disconnect or reset the check
engine lite with a scan tool because it will clear all the monitors that
have passed. Each monitor has its own procedures to pass, some actually have
to be driven at a certain speed under a certain load such as the EGR valve
which is one of the hardest monitor to run. I normally advise the cust to
drive it 2 weeks before they bring it back in for a test. It could take more
then 40 cycles or less then 5. It all depends on if the engine is driven as
the PCM monitor is looking for.

More then likely you have a cracked hose under the vehicle next to the
canister or a cracked hose behind the air cleaner housing.

Glenn Beasley
Chrysler Tech

 

Glenn,

Thanks for your reply to my question!

After I replaced the gas cap, I found myself in a predicament in
that I didn't know if or how long it would take the PCM to reset the
"check engine" light, or if I had even fixed the problem. The factory
service manual didn't provide any quantitative information in that area
(or if it did, I missed it).

Is the OBD-II arena such a "black art" in that there are no
quantitative definitions as to how each I/M is defined/reset? How do
Dodge/Chrysler dealers handle this type of situation on a service call -
can the DBM-II/III individually test/reset the failure codes and I/M
parameters?

Thank you again for your help!

George

 

Normally what some dealers/shop do when they know they fixed the vehicle is
to leave the check engine lite on. (some dont clear out the data) The lite
will go off on so many good trips depending on what the fault is. By
clearing a code or doing a battery disconnect like you did not only erases
the fault but it also clears out all montior. Or what is called carb
rediness

We can clear codes but that also clears Monitors. do a search or carb
readiness. This one I just googled may explain what you are asking.
http://www.neons.org/neontsb/TSB/25/250298.htm

1 . Evaporative Leak Detection Monitor - This test will require a cold start
(possibly an overnight soak either indoors or out depending on conditions).
The ambient (outside) temperature must be between 4' and 32' C (40 and 90 F)
with the engine coolant temperature within 6 C (10 F) of ambient/battery
temperature. Once the above criteria are met, use the pre-test/monitor test
screen on the DRB 111 to determine the remaining requirements.
2. Catalyst Monitor - The vehicle must be driven at highway speeds for the
time listed in the pre-test screen. If the vehicle is equipped with a manual
transaxle, use fourth gear to help meet the requirements.
3. EGR Monitor - It is necessary to maintain TPS, MAP, and RPM ranges listed
in the pre-test screen for this test to complete.
4. 02 Sensor Monitor - The vehicle must be driven and brought to a stop for
the time listed in the pre-test screen. Automatic transaxle vehicles must be
left in drive during the stop period.
5. Purge Monitor - To see a similar screen format as listed in Figure 1,
press the F1 key on the DRB 111 while in the Purge Flow Pre-Test screen. The
purge free (PF) cells must update and the monitor will attempt to run on
every other throttle closure. Automatic transaxle vehicles must be left in
drive for the test to run. If all parameters are met and the test still
will not run, place your foot on the brake, open the throttle to 1/4 and
then quickly close the throttle. This should allow the PF cells to update.
6. 02 Sensor Heater Monitor - The open throttle time for the 02 Heater
pre-test must be exceeded. This monitor will run after the ignition key is
switched "Off'. After the DRB 1110 switches to No Response (approximately 3
minutes) turn the ignition key "On" and check the 02 Sensor Heater monitor
status. It should have switched to "YES". All other monitors should be
completed before running this test.

Rear Wheel Drive

1 . 02 Sensor Heater Monitor - This test will require a cold start (possibly
an overnight soak either indoors or outdoors depending on conditions). The
ambient (outside) temperature must be between -18 and 38 C (0 and 100 F with
the engine coolant temperature within 6 C (10 F) of ambient/battery
temperature. Once the above criteria are met, use the pre-test/monitor test
screen on the DRB 111 to determine the remaining requirements.
2. Evaporative Leak Detection Monitor - This test will require a cold start
(possibly an overnight soak either indoors or outdoors depending on
conditions). The ambient (outside) temperature must be between 4 and 32 C
(40 and 90 F) with the engine coolant temperature within 6 C (10 F) of
ambient/battery temperature. Once the above criteria are met, use the
pre-test/monitor test screen on the DRB 111 to determine the remaining
requirements.
3. Catalyst Monitor - The vehicle must be driven at highway speeds for the
time listed in the pre-test screen. If the vehicle is equipped with a manual
transmission, use 4th gear to help meet the requirements.
4. 02 Sensor Monitor - The vehicle must be driven and brought to a stop for
the time listed in the pre-test screen. Automatic transmission vehicles must
be left in drive during the stop period.
5. Purge Monitor - To see a similar screen format as listed in Figure 1,
press the F1 key on the DRB 111 while in the Purge Flow Pre-Test screen. The
purge free (PF) cells must update and the monitor will attempt to run on
every other throttle closure. Automatic transmission vehicles must be left
in drive for the test to run. If all parameters are met and the test will
still not run, place your foot on the brake, open the throttle to 1/4 and
then quickly close the throttle. This should allow the PF cells to update.

 

this may help
disconnect the battery on a cold engine let it sit for 2 minutes then start up
vehicle.idle and let it reach op. temp then shut it off restart it and drive it
like a banshee up to 60 mph then pull off the road and shut it off then do this
again and it should reset the monitors or be every close to setting them so the
next time u drive it will
this is how i was told it could be done thru chryslers odb classes