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1997 Volvo 850 Question: what is the correct drive cycle to reset readiness monitor

 

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sandblasting101, Turbo, Salinas, CA, June 06, 2009, 12:01
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Just replaced the head and need to get smogged. I can't seem to find anyone who will tell me drive cycle needed to reset readiness monitor. Even Volvo dealers just tell me to drive it or pay up to 360.00 for to drive it for me. Can you help me with an answer? thnaks

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  • Answer #1

    patrick mannion from Greg Solow's Engine Room, June 06, 2009, 17:14
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    When you plug in a scan tool it looks at which monitors have been passed and which have not been passed. Some systems are checked every time the key is turned /car driven, other system require a particular drive cycle to be completed (evaporative emission, catalytic converter efficiency ect...) Do you know which monitor has not been passed. I have had to get some monitors to pass with the car jacked up on jack stands where I was unable to get it to pass drive cycle criteria on the road.

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    sandblasting101, June 06, 2009, 20:07
     Rookie

    I am pretty well versed on how the monitors are supposed to work, (have read extensive posts about similar problems), but would like to know how to go about getting them to reset. I have tried several formulas found on the net, but none have worked. I got them to reset once using a particular drive cycle, along with some unmonitored driving that I could not document, when a hose blew off the turbo aftercooler triggering the check engine light. at that time the monitors registered as ready but t after attaching the hose correctly and erasing the check engine light with a scanner, it cleared the readiness to not ready. No luck since then getting them to reset.

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    patrick mannion, June 07, 2009, 13:05
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    I have looked to try to find the Volvo drive cycle but can't find it. If all else fails we use a service called Identafix when we can't find information we need to fix a car. They charge about $25 to $30 and will email or fax you information
    http://www.identifix.com/Corp/contact_us.htm

    I will email you off line with info for Hyundai drive cycle information it explains drive cycle procedure it looks pretty close to what Volvo probably want.

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  • Answer #2

    Bret Bodas from RepairPal Test Shop, June 10, 2009, 20:18
     Master

    Resetting readiness monitors on this vehicle is very difficult. I used to perform these reset's all the time, but I always did it with a scan tool connected, which helped, but some were still very difficult. There is a service bulletin that describes the sequence fairly well, try to get that. Like Pat asked, "Do you know which monitors are not passing?"

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  • Medium-star Best Answer
    Visitor, June 18, 2010, 13:16

    Generic OBD II "Drive Cycle"
    Most OBD II ("On-Board Diagnostics II") diagnostic monitors will run at some time during normal operation of the vehicle.
    However, to satisy all of the different Trip enable criteria and run all of the OBD II diagnostic monitors, the vehicle must be driven under a variety of conditions. The following drive cycle will (theoretically) allow all monitors to run on (??) vehicle. (Note: Drive cycle specifics vary by vehicle!)
    1.Ensure that the fuel tank is between 1/4 and 3/4 full.
    2.Start cold (below 86°F /30°C) and warm up until engine coolant temperature is at least 160° F (typically requires at least one minute; up to 3 minutes).
    3.Accelerate to 40-55 MPH at 25% throttle and maintain speed for five minutes.
    4.Decelerate without using the brake (coast down) to 20 MPH or less, then stop the vehicle. Allow the engine to idle for 10 seconds, turn the key off, and wait one minute.
    5.Restart and accelerate to 40-55 MPH at 25% throttle and maintain speed for two minutes.
    6.Decelerate with using the brake [or the clutch!] by coasting down to 20 MPH or less, then stop the vehicle. Allow the engine to idle for 10 seconds, turn the key off, and wait one minute.

    The diagnostic routine shown above will be discontinued whenever:
    • Engine speed exceeds 3000 RPM
    • Large fluctuations in throttle angle
    • Road speed exceeds 60 MPH
    The driving criteria shown can be completed within the FTP required ~11 miles in a controlled environment such as a dyno test or test track.
    A “customer driving cycle” may vary according to traffic patterns, route selection and distance traveled, which may not allow the “diagnostic trip” to be fully ompleted each time the vehicle is operated.

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