2001 Chevrolet S-10 Repair Question
Secondary air/ evap monitor
Do you have the capability to see what dtc tests have run and passed, and/or run and not passed? It should be available on the scan tool. Once you have determined which have either not run, or not passed, you can look at the criteria for running the test, and see if there are specifics that are not being met.
Here is the typical drive cycle that I have shown, see if there is anything different than what you are doing.
Typical OBD II Drive Cycle
Diagnostic Time Schedule for I/M Readiness
Vehicle Drive Status
What is Monitored?
Cold Start, coolant temperature less than 50°C (122°F)
Idle 2.5 minutes in Drive (Auto) Neutral (Man), A/C and rear defogger ON
HO2S Heater, Misfire, Secondary Air, Fuel Trim, EVAP Purge
A/C OFF. accelerate to 90?km/h (55?mph), 1/2 throttle.
Misfire, Fuel Trim, Purge
3 minutes of Steady State - Cruise at 90?km/h (55?mph)
Misfire, Secondary Air, Fuel Trim, HO2S, EVAP Purge
Clutch engaged (Man), no braking, decelerate to 32?km/h (20?mph)
Fuel Trim, EVAP Purge
Accelerate to 90–97?km/h (55–60?mph), 3/4 throttle
Misfire, Fuel Trim, EVAP Purge
5 minutes of Steady State Cruise at 90–97?km/h (55–60?mph)
Catalyst Monitor, Misfire, Fuel Trim, HO2S, EVAP Purge
Decelerate, no breaking. End of Drive Cycle
Total time of OBD II Drive Cycle 12 minutes
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