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Discussion Starter #1
No matter what i do, it refuses to set. Old o2s, new o2s, constant drive cycles and cold start cycles.

Nothing works.
No CEL.
No codes.
All other monitors fully set including evap. I am at a loss on what to do. Even tried looking at the Jeep Wrangler TSB for the same issue to provide constant power to the ASD relay.

I am at a loss.
 

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Disconnect your battery for say 10 minutes for a try.
 

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No matter what i do, it refuses to set. Old o2s, new o2s, constant drive cycles and cold start cycles.

Nothing works.
No CEL.
No codes.
All other monitors fully set including evap. I am at a loss on what to do. Even tried looking at the Jeep Wrangler TSB for the same issue to provide constant power to the ASD relay.

I am at a loss.
It sounds like you need to get a pcm relearn or flash but I don't know if the dealer has any old equipment any more.

Mike S Grand caravan 3.3
 

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fix it if you can
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Have you completed a "drive cycle" with A/C off? If it's always ON, the clutch will prevent PCM from running O2S monitor...
 

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Discussion Starter #5
Have you completed a "drive cycle" with A/C off? If it's always ON, the clutch will prevent PCM from running O2S monitor...
Yes. AC isn’t working right now due to rear leak. All smog monitors fully set to ready except O2 heaters
 

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Discussion Starter #6
Disconnect your battery for say 10 minutes for a try.
I know I am gonna lose all the other smog monitors because of this. What would this do exactly regarding the O2 hester monitor exactly? I am at a loss as to why its not running. All the other monitors have long set to ready.
It sounds like you need to get a pcm relearn or flash but I don't know if the dealer has any old equipment any more.

Mike S Grand caravan 3.3


PCM is already on the latest software now. It makes no sense. Why did all the other amog monitors set to ready with zero issue?
 

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Disconnecting the battery gets the computer to reboot. It's a "glitch" solver.

Disconnect the negative terminal and touch the negative cable to the positive terminal, to speed up the process (clears residuals), then reconnect the negative terminal.
 

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Disconnecting the battery gets the computer to reboot. It's a "glitch" solver.

Disconnect the negative terminal and touch the negative cable to the positive terminal, to speed up the process (clears residuals), then reconnect the negative terminal.
I'm starting to think that the 02 is shorted to ground I don't know what exactly to do time to call Ivan at pinehollow

Mike S Grand caravan 3.3
 

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No matter what i do, it refuses to set. Old o2s, new o2s, constant drive cycles and cold start cycles. ....
I've been through this with various vehicles, and can say for certain that resetting this monitor can take a LONG time - frequently much longer than one would consider reasonable. Coincidentally, I just finished an episode for that monitor to reset on a Kia, which took 9 days of driving (around 300 miles) to occur. And every make and model has their own reset algorithm, so the set of events that resets it for a particular vehicle, does not work for others.

Although I can't tell you with absolute certainty that your monitor will reset, IMO if there are no codes, then it will take place after the PCM sees all of the events it needs to have. However, if the battery gets disconnected, then all of the reset events that have been accumulated thus far will be lost, and the PCM will have to start the entire reset process all over again from square one. I recommend just keep driving it for a few more days.
 

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I've been through this with various vehicles, and can say for certain that resetting this monitor can take a LONG time - frequently much longer than one would consider reasonable. Coincidentally, I just finished an episode for that monitor to reset on a Kia, which took 9 days of driving (around 300 miles) to occur. And every make and model has their own reset algorithm, so the set of events that resets it for a particular vehicle, does not work for others.

Although I can't tell you with absolute certainty that your monitor will reset, IMO if there are no codes, then it will take place after the PCM sees all of the events it needs to have. However, if the battery gets disconnected, then all of the reset events that have been accumulated thus far will be lost, and the PCM will have to start the entire reset process all over again from square one. I recommend just keep driving it for a few more days.
Yes a drive cycle is 300+ on a Chrysler I think 350-400 and it might take 1or2 cycles to reset.

Mike S Grand caravan 3.3
 

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Drivin' Maniac
2002 Grand Caravan ES 3.8L
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Don't know about our vans, but some cars require a certain amount of time, running at a certain speed. o_O Yes, they can be difficult to set.

But O2 heater faults usually are easy. Either they work (reset) or they don't ( open circuit to the heater wire on the O2). Since you replaced it several times, I'd suspect a bad wire or connector.
 

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Don't know about our vans, but some cars require a certain amount of time, running at a certain speed. o_O Yes, they can be difficult to set.

But O2 heater faults usually are easy. Either they work (reset) or they don't ( open circuit to the heater wire on the O2). Since you replaced it several times, I'd suspect a bad wire or connector.
That's correct the heater is right away if not then yes a broken wire

Mike S Grand caravan 3.3
 

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Discussion Starter #13
I am not getting any “circuit too low” “circuit too high” for the O2 heaters. Not a single CEL. I am not convinced its the wiring, as that would throw a CEL of some sort, maybe even a cat performance one. Nada. Runs like clockwork.

I haven’t done a 300mile drivecycle yet. Probably around 150 now, haven’t really been keeping track because I was following the “drivecycle” proceedures which have worked for all the other monitors
 

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Maybe the ambient temp in your area isn't allowing you to get fully cold to the point the heaters want to kick in. You need coolant below 80F in most cars.
 

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Drivin' Maniac
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Maybe the ambient temp in your area isn't allowing you to get fully cold to the point the heaters want to kick in.
My understanding is that the heaters speed up the ability for the O2 sensors to 'read' accurately, thus reducing the time that the emissions controls are in 'open loop'.

Not a function of ambient temps, just exhaust temp. (Although, they may take longer when it is cold out).
 
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It's not ambient temps, but engine temps that need to be below 80F. Lower ambient temp will just get it there faster.

On really warm days O2 heaters may not even cut on. Had a Cadillac in the shop this summer that had to be cranked in the middle of the night to clear its heater monitor.
 

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Discussion Starter #17
It's not ambient temps, but engine temps that need to be below 80F. Lower ambient temp will just get it there faster.

On really warm days O2 heaters may not even cut on. Had a Cadillac in the shop this summer that had to be cranked in the middle of the night to clear its heater monitor.


That’s what I am thinking and have been running drive cycles really early in the morning. This 2000+ obd2“smog test” is idiotic. No monitors allowed except evap. 1999 and older one monitor allowed of any kind. Well, it it was 1999 it would of passed.

Driving around aimlessly burning gas and polluting to prove to the state that your car “doesn’t pollute”. Complete crock of shit.
 

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fix it if you can
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Yes. AC isn’t working right now due to rear leak. All smog monitors fully set to ready except O2 heaters
When you turn ignition key on (before starting), does MIL turn on once for bulb check and go out or flash several times?

BTW, o2s Heater monitor is distinct from the main o2s... (you neglected to mention heater in your OP)
Take a spray bottle and lightly mist some water on the sensor(s) - just enough to speed up cooldown after you shut the engine off... (you may have to cool both sensors to get it to run the monitor - start with upstream, it's easier to reach. If that doesn't get it done, mist both)

FSM said:
Enabling Conditions—The following conditions must be met for the PCM to run the oxygen sensor heater test:

• Engine run time of at least 5.1 minutes
• Key OFF power down
• Battery voltage of at least 10 volts
• Sufficient Oxygen Sensor cool down

OPERATION—The Oxygen Sensor Heater Moni-
tor begins after the ignition has been turned OFF
and the O2 sensors have cooled. The PCM sends a 5
volt bias to the oxygen sensor every 1.6 seconds. The
PCM keeps it biased for 35 ms each time. As the sen-
sor cools down, the resistance increases and the PCM
reads the increase in voltage. Once voltage has
increased to a predetermined amount, higher than
when the test started, the oxygen sensor is cool
enough to test heater operation.
When the oxygen sensor is cool enough, the PCM
energizes the ASD relay. Voltage to the O2 sensor
begins to increase the temperature. As the sensor
temperature increases, the internal resistance
decreases. The PCM continues biasing the 5 volt sig-
nal to the sensor. Each time the signal is biased, the
PCM reads a voltage decrease. When the PCM
detects a voltage decrease of a predetermined value
for several biased pulses, the test passes.
The heater elements are tested each time the
engine is turned OFF if all the enabling conditions
are met. If the monitor fails, the PCM stores a
maturing fault and a Freeze Frame is entered. If two
consecutive tests fail, a DTC is stored. Because the
ignition is OFF, the MIL is illuminated at the begin-
ning of the next key cycle, after the 2nd failure.
[/qoute]
 

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GA does that too, but the amount is something like $2,000 spent on repairs. And if it's DIY, you don't get a deduction for your labor and can only claim parts; where an entire shop bill can be counted.
 
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