Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP
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.
DESCRIPTION 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.CONDITIONS FOR RUNNING Cold Start
DIAGNOSTIC AIDS 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.TEST DESCRIPTION
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".
no it isn't a new question... please don't hit accept again... it will debit your account again. sorry about that.