HO2 not ready
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Joined: Feb 2004
Posts: 751
From: Leesburg, VA
HO2 not ready
Please help me out here - this is the only monitor in obd2 pcm which is always not ready, and I need it to be ready to keep my plates. Many cold starts, no codes. Can it be programmed out / threshold modified / simulated input? Anybody has a description of what pcm expects from sensors for this monitor to change state?
How is pcm running this test and what it is looking for? All 4 heaters seems to work OK, at least no codes reporting breakage in heater circuit...
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From: Hell was full so they sent me to NJ
Re: HO2 not ready
It appears there are a number of items that must be met before the system check can even be run. I found this on a "GM Techs" post on a bulletin board. I don't know if it applies directly to the LT1, but it gives you an idea of the types of things that may prevent the "system ready" test from being run = system not ready. By the way, this HO2S system ready does not apply to the "heaters".... it applies to the heated O2 sensors.
Source:
GM Techs.........Emission System Question - Yellow Bullet Forums
DESCRIPTION
The purpose of this test is to satisfy the enable criteria necessary to execute I/M readiness diagnostics for the oxygen sensor (O2S, HO2S) system. The test may be used to set the I/M System Status to YES. Ensure the vehicle meets the requirements listed in Conditions for Running before performing this test. Failure to meet the necessary requirements may produce inaccurate test results.
CONDITIONS FOR RUNNING
The engine coolant temperature (ECT) is more than 70°C (158°F) .
The engine is running in Closed Loop fuel control.
The engine has been running for more than 1 minute .
The battery voltage is between 11.6-16 volts .
The fuel ethanol content is less than 15 percent .
The fuel level is more than 10 percent .
The purpose of this test is to satisfy the enable criteria necessary to execute I/M readiness diagnostics for the oxygen sensor (O2S, HO2S) system. The test may be used to set the I/M System Status to YES. Ensure the vehicle meets the requirements listed in Conditions for Running before performing this test. Failure to meet the necessary requirements may produce inaccurate test results.
CONDITIONS FOR RUNNING
The engine coolant temperature (ECT) is more than 70°C (158°F) .
The engine is running in Closed Loop fuel control.
The engine has been running for more than 1 minute .
The battery voltage is between 11.6-16 volts .
The fuel ethanol content is less than 15 percent .
The fuel level is more than 10 percent .
GM Techs.........Emission System Question - Yellow Bullet Forums
Thread Starter
Registered User
Joined: Feb 2004
Posts: 751
From: Leesburg, VA
It appears there are a number of items that must be met before the system check can even be run. I found this on a "GM Techs" post on a bulletin board. I don't know if it applies directly to the LT1, but it gives you an idea of the types of things that may prevent the "system ready" test from being run = system not ready. By the way, this HO2S system ready does not apply to the "heaters".... it applies to the heated O2 sensors.
Source:
GM Techs.........Emission System Question - Yellow Bullet Forums
Source:
GM Techs.........Emission System Question - Yellow Bullet Forums
Thread Starter
Registered User
Joined: Feb 2004
Posts: 751
From: Leesburg, VA
Ok, its ready now. What made a trick - several completely cold starts (hard to achieve in almost 100 degrees weather). So pcm was looking at the readings changes when going from open to closed loop. And it should be done several times....
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