2010 Buick Lacrosse emissions monitor question

rider47

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Hello Buick LaCrosse Owners,

Car background:

2010 Buick Lacrosse (93,456 odometer) fails state of Texas emissions test:

Issues:

Has P0442 – small evap system leak

Did have HO2 sensor issue (Bank2 Sensor 1) – has been fixed. No MIL is active

After completing HO2 sensor replacement, cannot get HO2 monitor test to complete
Successfully. I drive 200 miles per week to and from my workplace. I am following
Chiltons recommendation for Buick Lacrosse monitor test procedure:

Complete System Set Procedure for 2010 Buick

Turn off all accessories open hood

Set parking brake

Start engine - let idle for 2 min

Close hood - Release parking brake

Accelorate throttle (45-50 mph) maintain this speed for 8 minutes

continue to operate for additional 6 minutes (5 -8 Miles)

Accelerate to 55 mph for 2 minutes

Release accelorator pedal for 10 s (Allows vehicle to enter the decel fuel cut off

Note: Do not touch accelerator pedal (Invalidates Test)

Stop the vehicle with engine in drive - let vehicle idle for 2 minutes

Shift vehicle to park. Turn off engine and exit vehicle (Do not disturb for 45 minutes)

Apply scan tool - All I/M systems should say YES

*** Very difficult to follow this procedure exactly, as I am driving in rush hour traffic
Both to and from work.
State of Texas allows me to pass inspection with one emission code active (not two)

Q1: Has any fellow LaCrosse owners come up with this emissions issue?

Q2: Does anyone know how closely the monitor test procedure must be followed
In order for the monitor test to be invoked?
 
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Correct. I did thoroughly clean the gasket on my gas cap (gasket material is in good condition) and rotated it until it did several clicks as always. My issue is the HO2 sensor monitor.
The monitor needs to run and clear. This is not happening for me. I can pass my state inspection with P0442 failed, as long as HO2 monitor runs and clears. I need the HO2 sensor
monitor to clear. I am looking at having to replace the charcoal canister and the evap purge valve (mounted to it ) on my car to get past the P0442 issue (very expensive).
 
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#4
concerning the evap code, did you have a smoke test done before replacing all those parts?
concerning the O2 monitor, no H, did you replace the O2 sensor with a brand name part. The PCM may not like the responses it gets from the O2 sensor causing the readiness monitor to give you the issue. Read below what the O2 readiness cycle does.

Oxygen (O2) Sensor

The oxygen sensor monitor allows the PCM to verify that the O2 sensors are properly calibrated and functioning without noticeable deterioration under normal engine operating conditions. This ensures that when the PCM is controlling fuel mixture during closed-loop operation, an actual air/fuel ratio of 14.7:1 is being combusted in the cylinders. When the air/fuel ratio moves away from this ideal point catalytic converter efficiency decreases and emissions increase.

The PCM enables the oxygen sensor monitor after the engine and catalytic converter have been brought up to normal operating temperature, to reach closed loop operation, and the vehicle is maintaining a steady speed above 25 mph for several minutes. For the monitor to run, the check engine light needs to be commanded off by the PCM and the continuous monitors must have completed successfully.

The PCM tests all the oxygen sensors when the monitor is enabled. The upstream O2 sensors are checked for proper voltage threshold and response rate to air/fuel mixture changes (switching from rich to lean). The downstream O2 sensors are checked for proper voltage threshold and the ability to recognize lean conditions. Both sensors are monitored for signal rationality.

While the monitor is running, the PCM executes a fixed frequency fuel control routine and observes the upstream sensors’ output voltage and switching response frequency. The PCM also shuts off the fuel injectors during a period of deceleration and observes the downstream sensors’ voltage response to the lean condition.

The check engine light is illuminated by the PCM when an oxygen sensor fault has been detected after 2 drive cycles.
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#5
Wow, and in Maine the test still doesn't exist other than Cumberland County. They tried, so now one of the inspection stations is a restaurant lmao. Can canister medium be changed? Use charcoal and alum in my house water filters to keep arsenic below 1PPM (at .5), EPA thing and those filters are replenishable. Not same thing at all but I'd be looking very hard at that canister.

Also the test seems way too much that if something can go wrong it's positively going to. I would think in Texas the cars would be driven on a test road, brought back to the shop, a quick test and pass or not. Just saying the stuff is supposed to be working while out driving not per some designed to fail test procedure.
 
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2018 Regal Sportback - 2010 Yamaha R6 (track bike) Past cars: 92 LeSabre, 98 Regal, 02 GrandPrixGT
#6
The H02 is for the cat converter, and sometimes a 02 heater from GM is the best way to go.

All the emissions monitors when working properly should show complete within 5 minutes after the engine reached full operating temperature.

Is your O2 heater just showing " not ready " ? Some 02 heater sensors are sensitive to how far away they are from the cat, and thus sometimes installing a extension does the trick... The extension is a couple inches long bung that goes in the 02 bung and the 02 heater screws into it.. so the distance to the cat is extended a little.
 
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#8
he doesnt have a second code, the problem is the O2 monitor does not go to ready status after replacing an O2 sensor.
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Thread starter #9
concerning the evap code, did you have a smoke test done before replacing all those parts?
concerning the O2 monitor, no H, did you replace the O2 sensor with a brand name part. The PCM may not like the responses it gets from the O2 sensor causing the readiness monitor to give you the issue. Read below what the O2 readiness cycle does.

Oxygen (O2) Sensor

The oxygen sensor monitor allows the PCM to verify that the O2 sensors are properly calibrated and functioning without noticeable deterioration under normal engine operating conditions. This ensures that when the PCM is controlling fuel mixture during closed-loop operation, an actual air/fuel ratio of 14.7:1 is being combusted in the cylinders. When the air/fuel ratio moves away from this ideal point catalytic converter efficiency decreases and emissions increase.

The PCM enables the oxygen sensor monitor after the engine and catalytic converter have been brought up to normal operating temperature, to reach closed loop operation, and the vehicle is maintaining a steady speed above 25 mph for several minutes. For the monitor to run, the check engine light needs to be commanded off by the PCM and the continuous monitors must have completed successfully.

The PCM tests all the oxygen sensors when the monitor is enabled. The upstream O2 sensors are checked for proper voltage threshold and response rate to air/fuel mixture changes (switching from rich to lean). The downstream O2 sensors are checked for proper voltage threshold and the ability to recognize lean conditions. Both sensors are monitored for signal rationality.

While the monitor is running, the PCM executes a fixed frequency fuel control routine and observes the upstream sensors’ output voltage and switching response frequency. The PCM also shuts off the fuel injectors during a period of deceleration and observes the downstream sensors’ voltage response to the lean condition.

The check engine light is illuminated by the PCM when an oxygen sensor fault has been detected after 2 drive cycles.

Hi Mel,

I have yet to replace my charcoal canister and purge valve mounted on it (but thanks for the smoke test tip). My dash does not have
the 'check engine' light illuminated on it. I am reading my engine stats with Android app called "ODB Fusion". It shows P0442 and that
my HO2 Monitor and HO2 Sensor Heater have not yet successfully completed the test.
 
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Thread starter #10
Wow, and in Maine the test still doesn't exist other than Cumberland County. They tried, so now one of the inspection stations is a restaurant lmao. Can canister medium be changed? Use charcoal and alum in my house water filters to keep arsenic below 1PPM (at .5), EPA thing and those filters are replenishable. Not same thing at all but I'd be looking very hard at that canister.

Also the test seems way too much that if something can go wrong it's positively going to. I would think in Texas the cars would be driven on a test road, brought back to the shop, a quick test and pass or not. Just saying the stuff is supposed to be working while out driving not per some designed to fail test procedure.
Hi Rich,

As far as I know, I need to follow the Chilton's Manual procedure I have listed in my initial post. The question is: How carefully must
the procedure be followed in order to get the monitor to run. You would think GM allow a little 'slop' room instead of making
the procedure 'down to the letter'
 
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Thread starter #11
The H02 is for the cat converter, and sometimes a 02 heater from GM is the best way to go.

All the emissions monitors when working properly should show complete within 5 minutes after the engine reached full operating temperature.

Is your O2 heater just showing " not ready " ? Some 02 heater sensors are sensitive to how far away they are from the cat, and thus sometimes installing a extension does the trick... The extension is a couple inches long bung that goes in the 02 bung and the 02 heater screws into it.. so the distance to the cat is extended a little.
Hi Zero,

I replaced the original GM HO2 sensor (on Bank2 Sensor 1 position) with a Bosch unit from auto-zone. They did ask me whether I needed
the 'pre-cat' or 'post-cat' sensor (my case was pre-cat).

I read my engine status with an Android app called 'ODB Fusion' it displays my HO2 Monitor test as 'Not Complete'.

Thanks for the 'Extension' tip.
 
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Thread starter #12
Sounds like you have two codes set. One appears to be P0442. What is the other?

In H02, the H means "heated" 02 sensor.

Hi Don,

I have only one code set (P0442 - Small evap leak, which has to do with discharging gas tank fumes to a charcoal canister).
Yes, HO2 means heated oxygen sensor. I had P0050 before I changed out the HO2 sensor. That code is now gone.
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