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JOHN aka Eauto
JOHN aka Eauto, The Car Guy
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How long does it take to get EVAP monitor to reset?

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How long does it take to get the EVAP control & Seconday AIr System monitors to reset? The AIR pump was replaced 4 days ago and the DTC fault was reset. I currently have no DTC codes. the SES light is off. I have driven over 300 highway miles since the repair. I need to get my emmisions test to pass. The test has been rejected once. I have an Autotap and have been reading the emmission status through the ODB port. It says the EVAP & Seconday AIr System monitors are not ready.
it should be quick if you follow the drive cycle

A complete driving cycle will perform diagnostics on all monitored systems and can usually be completed in less than fifteen minutes.

Performing a GM OBD-II Driving cycle:

  • Cold Start In order to be classified as a cold start the engine coolant temperature must be below 122?F (50?C) and within 11?F (6?C) 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 55mph (88km/hr) is reached. During this time the Misfire, Fuel Trim, and Purge Flow diagnostics will be performed.
  • Hold Steady Speed Hold a steady speed of 55mph (88km/hr) 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 20 mph (32km/hr). During this time the EGR, Purge and Fuel Trim diagnostics will be performed.
  • Accelerate Accelerate at 3/4 throttle until 55-60mph (88-96 km/hr). This will perform the same diagnostics as in step 3.
  • Hold Steady Speed Hold a steady speed of 55mph (88km/hr) 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.
Customer: replied 7 years ago.

I have two questions.

1. Would driving 300 highway miles not reset the EVAP & Seconday AIr System monitors.

2 Which step above resets the EVAP & Seconday AIr System monitors? I did not see those listed.

Those are the only two that are not ready. All others are OK.

Thank you

step 3 it can take a while if not performed in sequence...And if the engine light is on a drive cycle will not complete...Sometimes it takes a few drive cycles for everything to click

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. Accelerate. Accelerate at 3/4 throttle until 88-96 km/hr (55-60mph). This will perform the same diagnostics as in step 3.

  7. 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.

  8. Decelerate. This will perform the same diagnostics as in step 5. Again, don't press the clutch or brakes or shift gears
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