EVAP monitor is not ready

Question

2017 Chevy Traverse Premier FWD 85,000

In Mode 6 I’m getting a lot of EVAP monitor is not ready indicators, highlighted in yellow.
I have no check engine light, no codes and no drive ability issues. I’ve looked a Mode 6 in the past and have never had these monitor not ready indicators highlighted in yellow, everything’s always been green.

A couple of weeks ago I had a P0442 code and replaced the Vapor Canister Purge Valve and gas cap and erased the code. That fixed the problem. All was green in Mode 6. The car passed the state emissions inspection here in Texas.

What’s going on now?

Thanks!

jack62 · Accepted Answer

The answer to, "What's going on now?" is:

The prerequisite drive cycle(s) criteria hasn't been met for the ECU to complete the EVAP monitors yet.

If you don't have any codes or pending codes and you aren't closing in on having to bring your car to vehicle inspection then I/M Readiness (Inspection/Maintenance Readiness) doesn't mean anything.

The engine computer monitors the components 2 ways. Continuous Monitors and Non-Continuous monitors.

The continuous monitoring are stuff like RPMs, speed sensors, coil voltage feedback, misfires, injector voltage feedback, controls like anything in the ETC (electronic throttle control) circuit, IAC, TPS (throttle position sensor), APP (accelerator Position sensor) MAF, MAP, O2 sensor voltages (although O2 heater performance is tested in non continuous) , not to mention communication with various control modules .... all that kind of stuff.

Any problem here and the computer will throw a code and depending on the component it may even put the vehicle in "Limp Mode" or shut the throttle plate.

You're talking about non-continuous monitoring, which require specific drive cycle criteria.

I'd just give it more time (( however, I'm a somewhat "enlightened" old man and I understand that you aren't me and maybe you want to pursue this)).

So, this all starts with the vehicle meeting "Cold Start" criteria even before "drive cycle" criteria can be met to run the monitors. If the Cold Start criteria isn't met on a particular drive cycle the monitors won't be ran during the rest of that drive cycle.

Conditions for Meeting a Cold Start
• The ignition voltage is between 11-18 volts.
• The barometric pressure (BARO) is more than 75 kPa.
• The start-up engine coolant temperature (ECT) is above 40°F and below 122°F
• The start-up intake air temperature (IAT) is above 40°F and below 122°F
• The ambient air temperature is above 40°F and below 122°F

• The difference between the ECT, IAT, and Ambient Temp Sensors' temperatures are less than or equal to 10.8°F of each other.
• Fuel level is between 15-85 percent

So it would be pretty easy to determine if Cold Start criteria is being met by observing the battery voltage, and MAP sensor data.

Then just be sure that on a Cold Start (typically the 1st start of the day) That your ECT, IAT, and Ambient Air Temperature sensors are all reporting less than 122°F and less than 11°F difference of each other.

Be sure your fuel tank isn't above 3/4 or under 1/4.

Then you can try fulfilling GM's generic "driving cycle requirement"

General Motors Driving Cycle

A complete driving cycle should perform diagnostics on all systems. A complete driving cycle can be done in under fifteen minutes.

To perform an OBDII Driving cycle do the following:

Cold Start. In order to be classified as a cold start the engine coolant temperature must be below 50°C (122°F) and within 6°C (11°F) of the ambient air temperature at startup. Do not leave the key on prior to the cold start or the heated oxygen sensor diagnostic may not run.
Idle. The engine must be run for two and a half minutes with the air conditioner on and rear defroster on. The more electrical load you can apply the better. This will test the O2 heater, Passive Air, Purge "No Flow", Misfire and if closed loop is achieved, Fuel Trim.
Accelerate. Turn off the air conditioner and all the other loads and apply half throttle until 88km/hr (55mph) is reached. During this time the Misfire, Fuel Trim, and Purge Flow diagnostics will be performed.
Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for 3 minutes. During this time the O2 response, air Intrusive, EGR, Purge, Misfire, and Fuel Trim diagnostics will be performed.
Decelerate. Let off the accelerator pedal. Do not shift, touch the brake or clutch. It is important to let the vehicle coast along gradually slowing down to 32km/hr (20 mph). During this time the EGR, Purge and Fuel Trim diagnostics will be performed.
Accelerate. Accelerate at 3/4 throttle until 88-96 km/hr (55-60mph). This will perform the same diagnostics as in step 3.
Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for five minutes. During this time, in addition to the diagnostics performed in step 4, the catalyst monitor diagnostics will be performed. If the catalyst is marginal or the battery has been disconnected, it may take 5 complete driving cycles to determine the state of the catalyst.
Decelerate. This will perform the same diagnostics as in step 5. Again, don't press the clutch or brakes or shift gears.

Be aware that some of these monitors need as many as 5 driving cycles meeting the criteria to complete their tests.

So doing this once may not be enough

albatross · Answer

Thanks. I’ll give it a bit more time.