Smog check - oxygen sensor not ready

[03 raw nsx]

I went for a smog check and couldn’t get tested - Twice.
Couldn’t get past the oxygen sensor, oxygen sensor not ready?

Does anyone know the drive cycle that needs to be done to set the oxygen sensor?

TIA
Rich Wong

 

[solidol]

I went for a smog check and couldn’t get tested - Twice.
Couldn’t get past the oxygen sensor, oxygen sensor not ready?

Does anyone know the drive cycle that needs to be done to set the oxygen sensor?

TIA
Rich Wong

Sure it's not dead? I'm not aware of any bootstrapping.. it's a dumb sensor.

 

[LithiumIon]

Sure it's not dead? I'm not aware of any bootstrapping.. it's a dumb sensor.

I had a similar problem with my 96. Following a dead battery I had to drive about 100 miles for the O2 sensor to accumulate enough data. I have a cheap OBD2 reader and I could see when each of the sensors was ok to test- this one took the longest.


Sent from my iPhone using Tapatalk

 

[solidol]

I had a similar problem with my 96. Following a dead battery I had to drive about 100 miles for the O2 sensor to accumulate enough data. I have a cheap OBD2 reader and I could see when each of the sensors was ok to test- this one took the longest.


Sent from my iPhone using Tapatalk

It's not a sensor that accumulates data. It's your ecu that builds stats for open loop op.

 

[LithiumIon]

It's not a sensor that accumulates data. It's your ecu that builds stats for open loop op.

Well obviously the sensor itself has no memory in it- it's just a sensor. The OP was asking about what he needs to do to pass a smog check and I was telling him about my experience. Whether his car is the same as mine I don't know.


Sent from my iPhone using Tapatalk

 

[03 raw nsx]

It's not a sensor that accumulates data. It's your ecu that builds stats for open loop op.

According to the Smog Check station....
if you battery fell below 5v the data in the ECU is cleared and you need to do a 'drive cycle' reset.
In either case, the smog check machine red flagged the O2 sensor as 'not ready'

 

[jwmelvin]

Others have suggested the OBD2 drive cycle but I've not seen anything definitive. I know that I reset my car before driving it from Florida to Virginia (~900 miles), and some of the monitors were not in a ready state. And then I drove around town here in Virginia for a couple days (~40 miles) and they flipped into the ready state. Here is what my notes say when I looked for the drive cycle online (source unknown but see here, which perhaps came from here):

• Cold start (122 F) from ignition off
• Idle 2.5 min w/ A/C & defrost (O2 sensor heater, air pump, evap purge)
• Turn A/C & defrost off
• Accelerate to 55 mph at half throttle (misfire, fuel trim & canister purge)
• Hold at 55 mph for 3 min (EGR, air pump, O2 sensors, canister purge)
• Coast down to 20 w/ no brake or clutch (EGR, purge)
• Accelerate to 55-60 mph at 75% throttle (misfire, fuel trim, purge)
• Hold 55-60 mph for 5 min (cats, misfire, EGR, fuel trim, O2 sensors, purge)
• Coast to a stop w/ no brake (EGR, canister purge)

 

[Old Guy]

I went for a smog check and couldn’t get tested - Twice.
Couldn’t get past the oxygen sensor, oxygen sensor not ready?

Does anyone know the drive cycle that needs to be done to set the oxygen sensor?

TIA
Rich Wong

Oxygen sensor not ready - was that a code that came up on a code reader or was it something that came up on the tool at the SMOG check station? If it came up on the code reader what was the associated code number because that error code description is not listed in the service manual.


If it is a message that came up on the SMOG station instrument, it is possible that it is monitoring the difference between long term and short term fuel trim. If the instrument measures lots of short term trim and no long term trim, or trims that are in the opposite direction that is an indication of a problem. Any test carried out on a car that is maxing out on short term trims because the long term trims have been zeroed may be invalid as the results will likely change after the long term trims get populated.

Did you by any chance reset your ECU prior to doing the smog test? As I recall, when you reset the ECU you erase the long term trim value. This might be causing high short term trim values until the ECU has had enough operating data accumulated to populate the long term trim and reduce the short term trim value. That would kind of jive with LithiumIon's experience.

 

[Larry Bastanza]

Somewhere between 50-100 miles should do it. The key is the driving must be diversified. You need around town as well as highway miles so the system is run through all modes to get it "ready".

HTH,
LarryB

 

[03 raw nsx]

Took the car on a drive down Hwy1 from San Francisco to Half Moon Bay......Finally ready for Smog Check.
Yea!! Passed

Thanks
LarryB

 

[Spa2KJT]

Others have suggested the OBD2 drive cycle but I've not seen anything definitive. I know that I reset my car before driving it from Florida to Virginia (~900 miles), and some of the monitors were not in a ready state. And then I drove around town here in Virginia for a couple days (~40 miles) and they flipped into the ready state. Here is what my notes say when I looked for the drive cycle online (source unknown but see here, which perhaps came from here):

• Cold start (122 F) from ignition off
• Idle 2.5 min w/ A/C & defrost (O2 sensor heater, air pump, evap purge)
• Turn A/C & defrost off
• Accelerate to 55 mph at half throttle (misfire, fuel trim & canister purge)
• Hold at 55 mph for 3 min (EGR, air pump, O2 sensors, canister purge)
• Coast down to 20 w/ no brake or clutch (EGR, purge)
• Accelerate to 55-60 mph at 75% throttle (misfire, fuel trim, purge)
• Hold 55-60 mph for 5 min (cats, misfire, EGR, fuel trim, O2 sensors, purge)
• Coast to a stop w/ no brake (EGR, canister purge)

This is the correct process. When I did this a couple years back after I changed my 02 sensors, they were then ready. Normal driving for X miles will not enable you to pass a smog check. If you have an OBDII reader, you can perform a scan (depending on model) after completing the drive cycle to determine if you will pass smog before the test is completed. That's what saved me a trip to the MVC for inspection.

 

[rizarefaldi]

I went for a smog check and couldn’t get tested - Twice cara membuat nomor halaman di word
Couldn’t get past the oxygen sensor, oxygen sensor not ready?

Does anyone know the drive cycle that needs to be done to set the oxygen sensor?

TIA
Rich Wong

sorry bumping this thread, so it is between 50-100 miles, right?