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michael, ASE Certified Technician
Category: Chevy
Satisfied Customers: 667
Experience:  17 ASE Cert.; over 20 yrs. exp./18 with GM
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2001 chevy s10: pass inspection..battery was already driven

Customer Question

my 2001 chevy s10 didn't pass inspection because the monitors were not ready. the battery died last month and was fixed, so the mechanic thought that the monitors hadn't gone through their cycle yet, but I felt sure it was already driven enough to go through the cycle. any thoughts on what else may be wrong?
Submitted: 6 years ago.
Category: Chevy
Expert:  michael replied 6 years ago.

hello. below is the complete procedure for completing a drive cycle and getting the emissions system ready for testing. if the system STILL isn't ready for testing after this procedure... there may be another issue that needs to be diagnosed... like a faulty O2 sensor.


The purpose of the 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 trips for those particular diagnostics. When all diagnostic tests are completed, the I/M System Status indicators are set to YES. Perform this test when more than one or all of the I/M System Status indicators are set to NO.


Cold Start

  • The barometric pressure (BARO) is more than 74 kpa .
  • The engine coolant temperature (ECT) is below 30°C (86°F) .
  • The intake air temperature (IAT) is below 30°C (86°F) .
  • The difference between the intake air temperature (IAT) and the engine coolant temperature (ECT) is 8°C (14°F) or less.
  • The battery voltage is between 9-18 volts .
  • The fuel level is between 1/4 and 3/4.

Rough road conditions may prevent some of the tests from running. Extreme high or low ambient temperatures may prevent tests such as heated oxygen sensor (HO2S) heater and evaporative emission (EVAP) system from initiating. If a step is interrupted before completion, perform the remaining portion of the set procedures. Any portion of the set procedure that requires the engine at operating temperature may be repeated. This allows most of the diagnostics to run and the remaining tests can be performed using the individual System Set Procedures.

If the vehicle has recently run, start this procedure at step 3. This will allow the tests that require the engine at operating temperature to run. Using this method allows shorter cool down periods if the tests requiring a cold start do not initiate.

The scan tool can be used to monitor each of the I/M System Status indicators during the I/M Complete System Set Procedure. When all of the indicators for a test step have updated to YES, testing can move on to the next step even if the remaining portion of the test is not complete. For example, step 3 is designed to run the EVAP, secondary air injection (AIR), and HO2S tests. The procedure instructs the technician to operate the vehicle in the enable conditions for 6 minutes . If all 3 tests have updated to YES within 4 minutes , it is not necessary to continue with the enable conditions and testing can advance to the next step.


Steps 1-4

Steps 5-7

The numbers below refer to the step numbers on the diagnostic table.

  1. Make sure you perform the I/M System Check before performing this test. Failure to do so may result in difficulty updating the status to YES. See: Computers and Control Systems\Testing and Inspection\Monitors, Trips, Drive Cycles and Readiness Codes\Inspection/Maintenance (I/M) System Check
  2. This step is to run the HO2S Heater Tests and initiate the EVAP System Test. Preprogramming the scan tool will reduce the amount of time the oxygen sensor heaters operate while verifying the enable criteria. The engine control module considers the engine to be cold if the following conditions are met:
    • ECT less than 30°C (86°F)
    • ECT and IAT are within 8°C (14°F) of each other at start up
  1. This step is to run the EVAP, AIR and the Oxygen Sensor Tests. The EVAP Test begins once the engine coolant reaches a calibrated temperature. The AIR Test, if equipped, begins shortly after Closed Loop and the indicated speed is achieved. The Oxygen Sensor Tests begin once the engine is at operating temperature, in Closed Loop fuel control, and a calibrated amount of time has elapsed.
  2. This step is to run the exhaust gas recirculation (EGR) Tests. The EGR Tests are run during a gradual deceleration with a closed throttle. The vehicle speed is required in order to maintain a high, steady MAP signal.
  3. This step is to run the Catalyst Tests. This test runs during the idle period immediately following a cruise period that meets a minimum calibrated RPM and time period.
  4. Perform the individual system test for any of the systems that do not update to YES.
  5. The I/M System Status only reports on whether or not a diagnostic has run, not what the outcome of the test was. If any emission related DTC sets after the tests are complete, the DTC will require diagnosis
michael, ASE Certified Technician
Category: Chevy
Satisfied Customers: 667
Experience: 17 ASE Cert.; over 20 yrs. exp./18 with GM
michael and 9 other Chevy Specialists are ready to help you
Customer: replied 6 years ago.
Michael, I will pay for your time, but I would like to say that i had already found how to run the drive cycle by looking it up online. my question was, what else may be wrong if that doesn't fix the problem.
Expert:  michael replied 6 years ago.

IF the drive cycle will not allow all of the I/M flags to become "ready"... the most common failure is having too much or too little fuel in the vehicle or a fault with an O2 sensor. but if you don't have an SES light on... then i doubt you have any issues with any emission related components.


i'd suggest going by a local auto parts store and have the vehicle checked for trouble codes... if ANY are found they will have to be checked to see if they inhibit I/M flags from becoming "ready".


as for the fuel level in the vehicle... if it's lower than 15% or higher than 85%... it will inhibit the EVAP system from becoming "ready".

Customer: replied 6 years ago.
Thank you. I don't quite "get" if this additonal answer of my question consitutes a new question? I was thinking it was the answer to my original question which I have already paid for. What do you think?
Expert:  michael replied 6 years ago.

no it isn't a new question... please don't hit accept again... it will debit your account again. sorry about that.

Customer: replied 6 years ago.
Thank you! I will see if I can get back to the Feedback section and leave you positive feedback. Appreciate your honesty!
Expert:  michael replied 6 years ago.
thank you. and thanks for using Just Answer.

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