Volvo: Drive cycle to reset check enging light, emission control system, self diagnostics

Question
My wife pulled our 2001 C70 out of a gas station w/out putting the gas cap on, triggering the check engine light (warning of a problem with the emission control system).  We had the car checked (it was fine), and the mechanic manually turned the CE light off.  That was maybe 100 miles ago. But apparently the self-diagnostics haven't been completed, and I'm having trouble getting the car smogged. No local mechanic has really been able to help (one says I'll need to drive it 700-1000 miles; another says drive it at 50mph for 10 minutes; it seems to be a mystery).  Is there somewhere that I can find the exact drive cycle we need to put the car through so that the self-diagnostics can be completed, and the car will be ready to be smog tested?  Do I really need to drive it for a month and just hope?  Thank you.

Answer
Brian,
Begin Drive Cycle
The vehicle should be driven approximately 7.5 miles within a period of approx. 23 minutes (1372 seconds) from a cold start. However, due to manufacture variations, it is necessary to perform only as much of the Drive Cycle as is necessary to reset the required monitors to a "Ready" status. Operate the throttle smoothly to obtain best results. Do not shut the engine off during the drive cycle.

CAUTION: Obey all traffic laws and drive in a safe manner!

NOTE: Extreme driving conditioning such as very high/low temperatures, rough roads and high altitudes may prevent some monitors from attaining a "Ready" status.
Step 1   (Engine Cold) Start engine, idle 20 seconds. Accelerate gradually and drive at 20-25 mph for 1 minute, varying speed.
Step 2   Accelerate gradually to 32 mph within 35 seconds. Decelerate to 0 mph in 10 seconds. Idle for 40 seconds.
Step 3   Accelerate at part throttle to 25 mph in 10 seconds. Cruise at 17-25 mph for 15 seconds. Accelerate gradually to 57 mph in 45 seconds. Cruise at 50-56 mph for 1 minute. Decelerate gradually to 0 mph in 40 seconds. Idle for 15 seconds.
Step 4   Accelerate at part throttle to 36 mph and maintain for 10 seconds. Decelerate to 0 mph in 15 seconds. Idle for 5 seconds.
Step 5   Accelerate to 30 mph and back to 0 mph within 30 seconds. Idle for 20 seconds.
Step 6   Accelerate to 36 mph in 20 seconds. Drive at 35 mph for 20 seconds. Decelerate to 0 mph in 15 seconds. Idle 5 seconds.
Step 7   Accelerate gradually to 26 mph and decelerate to 0 within 40 seconds. Idle 15 seconds.
Step 8   Accelerate to 27 mph in 40 seconds. Decelerate to 0 mph in 10 seconds. Idle 25 seconds.
Step 9   Accelerate to 26 mph in 15 seconds, maintain speed for 10 seconds, decelerate to 0 mph in 10 seconds. Idle 15 seconds.
Step 10   Accelerate to 23 mph in 20 seconds, decelerate to 0.5 mph in 10 seconds (no complete stop). Accelerate to 28 mph and back to 0 mph (momentary stop 1 second) within 35 seconds.
Step 11   Accelerate gradually to 34 mph in 45 seconds. Vary speed between 34 and 19 mph for 2 minutes. Decelerate from 25 to 0 mph in 25 seconds. Idle for 5 seconds.
Step 12   Accelerate to 29 mph in 15 seconds, decelerate gradually to 0 mph in 45 seconds. Idle for 30 seconds.
Step 13   Accelerate gradually to 28 mph and back to 0 mph (momentary stop 1 second) within 50 seconds. Accelerate gradually to 27 mph and back to 0 mph within 55 seconds. Idle for 15 seconds.
Step 14   Accelerate to 24 mph and back to 0 mph within 18 seconds. Idle for 10 seconds. Accelerate gradually to 22 mph and back to 0 mph within 50 seconds. Idle for 8 seconds.
Step 15   Accelerate gradually to 30 mph within 50 seconds. Decelerate to 0 mph in 10 seconds. Idle for 25 seconds.
Step 16   Accelerate to 23 mph and back to 0 mph within 30 seconds. Idle for 10 seconds.
Step 17   Repeat steps 1 - 16 once again. Recheck the status of the "Readiness Monitors".


NOTE: Remember, clearing DTC's or interrupting power to the ECM after the readiness monitors have been reset to "Ready" will require that the Drive Cycle be repeated.

Completing the Drive Cycle successfully one (1) time should reset most drive cycle monitors to a "Ready" status. However, there are "two trip" monitors, which require that the drive cycle be successfully completed two (2) times, to achieve a "Ready" status. Furthermore, systems which use averaging, may require the drive cycle to be completed more than 2 times. It is necessary to perform only as much of the Drive Cycle as is necessary to reset the required monitors to a "Ready" status.

End Drive Cycle