GM Rediness Monitors

[svl208]

I'm having trouble getting 2 monitors to go ready. 2007 Silverado Classic 1500 2wd - Swapped in a LQ4 6.0L, long tube headers, no cats, no rear O2 Sensors. The Evap and 02 monitor won't set and I got emissions to pass. Here's the tune I'm running in the truck. Any help would be appreciated. Thanks!

[5FDP]

The o2 sensor monitor is likely to never set because you are missing the cats and 2 o2 sensors that complete the oxygen sensor system.

The EVAP one could take a while on some vehicles.

[svl208]

I'm allowed one not set to pass emissions. If O2 is out the window? Any tips on the evap monitor. I've had a 1/4 to 3/4 tank, drove it, idles for 4 mins and nothing on evap.

[blindsquirrel]

Oxygen Sensor and Oxygen Sensor Heater are described as two separate readiness monitors, so you'll fail if you're only allowed one freebie. The service manual has some pretty detailed info on all this and also on the drive cycle requirements for each monitor, which are way WAY more involved than 'I drove it then let it idle'.

[svl208]

Do u by chance have the info from the GM service manual?

[CrazyCanadian]

You wont get Evap to set until you get O2 to pass.. Part of the evap monitor requires valid O2 sensor readings in order to set. So it requires that monitor to pass before it will run the evap test.

[svl208]

Well that ain't good news! Lol. Well than I'm probably gonna have to put a couple cats and Rear o2 sensors to pass. U think 2 cheap Flow through cats will work? Or expensive correct cats?

[TheMechanic]

I always just use the forced EVAP test but here you go
GM Service InformationHome Publications Number Search New Bulletins Bulletin Search Feedback TIS2Web SI Help
2007 Chevrolet Silverado Classic - 2WD | Sierra Classic, Silverado Classic VIN C/K Service Manual | Engine | Engine Controls and Fuel - 4.8L, 5.3L, and 6.0L | Document ID: 1614137
Inspection/Maintenance Complete System Set Procedure
Diagnostic Fault Information
Important: Always perform the Inspection/Maintenance System Check prior to using this diagnostic procedure.

Description
The purpose of the Inspection/Maintenance (I/M) complete system set procedure is to satisfy the enable criteria necessary to execute all of the I/M readiness diagnostics and complete the drive cycles for those particular diagnostics. When all I/M monitored diagnostic tests are completed, the I/M System Status indicators are set to YES. Perform the Inspection/Maintenance (I/M) Complete System Set Procedure if any I/M System Status indicators are set to NO.

Conditions for Meeting a Cold Start
The ignition voltage between 11?18 volts.
The barometric pressure (BARO) is more than 75 kPa.
The start-up engine coolant temperature (ECT) is between 4?30?C (39?86?F).
The start-up intake air temperature (IAT) is between 4?30?C (39?86?F).
The difference between the IAT and the ECT is less than or equal to 6?C (10.8?F)
The ambient air temperature is between 4?30?C (39?86?F).
Fuel level is between 15?85 percent
Without RPO L59?The fuel alcohol content is less than 15 percent.
With RPO L59?The fuel alcohol content is less than 87  percent.
Circuit/System Verification
Review the Inspection/Maintenance (I/M) System Status indicators with a scan tool. All I/M System Status indicators should report YES.

Inspection/Maintenance (I/M) System Set Procedure
Important: Whenever the ignition is turned ON, ignition positive voltage is supplied to the heated oxygen sensor (HO2S) heaters. After verifying the enable criteria, turn OFF the ignition for approximately 5 minutes to allow the sensors to cool before continuing with the test. Once the engine is started, do NOT turn the engine OFF for the remaining portion of the set procedure.

Ensure that the vehicle meets the conditions for a cold start listed above.
If the evaporative emission (EVAP) I/M System Status indicator displays NO, perform the EVAP Service bay test if available.
If the EVAP Service bay test is NOT available, it may take up to 6 drive cycles, with up to 17 hours between drive cycles, for the EVAP I/M System Status indicator to transition to YES.
If the O2S Heater System Status indicator displays NO, ensure that the ignition has been turned OFF for at least 10 hours.
Set the vehicle parking brake and ensure the vehicle is in park for automatic transmission or neutral for manual transmission.
Turn OFF all accessories; HVAC system, other electrical loads, including aftermarket/add-on equipment, etc.
Start and idle the engine for at least 2 minutes and until 65?C (149?F) is achieved.
Run the engine for 6.5 minutes within the following conditions:
MAF parameter between 4?30 g/s
Engine speed steady between 1000?3000 RPM
Return the engine to idle for 1 minute.
Apply and hold brake pedal, and shift to Drive for automatic, or apply clutch pedal for manual and operate the vehicle within the following conditions for 2 minutes:
Depress the accelerator pedal until TP Sensor angle is more than 2 percent.
MAF signal between 15?30 g/s
RPM steady between 1200?2000 RPM
Important: Do NOT touch the accelerator pedal during the idle period. A change in TP Sensor angle or an increase in engine speed may invalidate this portion of the test.

Release the accelerator pedal and shift the vehicle to Park for automatic, or Neutral and release clutch pedal for manual, and allow the engine to idle for 2 minutes.
Quickly depress the accelerator pedal until TP Sensor Angle is more than 8 percent and return to idle, repeat 3 times.
Allow engine to idle for at least 2 minutes.
Caution: Refer to Road Test Caution.

Release the parking brake and drive vehicle at 24 km/h (15 mph) or slower for 2 minutes.
Continue to drive the vehicle for at least 5.5 miles between 45?112 km/h (28?70 mph) with the vehicle reaching at least 80 km/h (50 mph).
Release the accelerator pedal for at least 2 seconds. This will allow the vehicle to enter decel fuel cut-off.
Depress the accelerator pedal until the TP Sensor angle is increased 3?20 percent and maintain a safe speed for 1 minute.
Safely stop the vehicle, with the engine in drive for automatic or in neutral with the clutch pedal depressed and parking brake applied for manual, idle for 2 minutes.
Shift to Park for automatic and apply the parking brake, or neutral and release clutch pedal for manual.
Important: Do NOT disturb the vehicle or turn ON the ignition until told to do so. Disturbing the vehicle may invalidate this portion of the test.

Turn OFF the ignition and exit the vehicle. Do NOT disturb the vehicle for 45 minutes.
Observe the Inspection/Maintenance (I/M) System Status with a scan tool. All of the I/M System Status indicators should display YES.
If the EVAP I/M System Status indicator displays NO turn OFF the ignition for 17 hours, ensure that the vehicle meets the conditions for a cold start, and repeat steps 12?18 six more times, or until the EVAP I/M System Status indicator transitions to YES. If the indicator continues to display NO, refer to the Inspection/Maintenance (I/M) System DTC Table to identify the DTCs that did not run. Follow the Conditions for Running the DTC in order to set the EVAP I/M System Status indicator.
If any of the I/M System Status indicators display NO, refer to the Inspection/Maintenance (I/M) System DTC Table for the indicator which did not display YES. The I/M System DTC Table identifies the DTCs associated with each I/M System Status Indicator. Follow the Conditions for Running the DTC in order to set the associated status indicator.
? 2022 General Motors. All rights reserved.

[TheMechanic]

Replace each ? with a dash -
Formatting issue

[CrazyCanadian]

2 cheap high flows with O2 extenders would probably do the trick

[mporte1983]

i just plug in rear 02 and ziptie to inside frame so ecm can see it