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Thread: Check engine light P0720

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    Check engine light P0720

    I got a car that was just started and the engine light came on. The only code I see is P0720-output speed sensor circuit. No abs or traction control lights are on. I tried to clear the light but no dice. Car only has 77000kms on it. I really don't want to take it dealer cause they're slower than the second coming of Christ but that's what warranty is for I guess. Figured I'd see if anyone else had this code. It's -20c/-4F here and cold weather seems to bring out all the problems.

    Edit:Light is now out but code is still stored. My scanner can only read the engine codes so I can't clear or read the tcm codes. It works fine with 2017 Nissans though.


    Last edited by Fummins; 11-21-2017 at 05:29 PM.

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    Senior Member Top_Fuel's Avatar
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    Hmmm...did you see this thread from over the weekend discussing this sensor's location?

    Does the car have any driveability or shifting issues (assuming it's a CVT)?

    I have an older (1999) Eclipse and have had the output speed sensor go bad a couple of times. This is a non-ABS car. When it happens, the speedometer doesn't work and the car will only limp along in 2nd gear. The sensor is nothing more than a magnetic pickup externally threaded into the transmission. It can be replaced by just popping the hood and screwing in a new one. It can be checked just by measuring its resistance. Not sure if this is the same thing in the Mirage. I didn't even bother taking the car in to have it done under warranty because the sensor wasn't expensive.

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        click to view fuel log View my fuel log 2015 Mirage ES 1.2 manual: 51.5 mpg (US) ... 21.9 km/L ... 4.6 L/100 km ... 61.8 mpg (Imp)


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    Daox (11-21-2017),Fummins (11-21-2017)

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    Yeah it's a cvt. The driver said it had no power when they drove it around the parking lot. I cleared the light and took it for a drive. All seems good now. Not sure exactly wth happened it's been good for half the day so far. Will post again if it comes back.

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    Not sure if this has been covered, but here's some info from the service manual.

    Quote Originally Posted by Mitsubishi Mirage Service Manual section 23A page 33
    DTC P0720: Malfunction of Output Speed Sensor

    DIAGNOSTIC FUNCTION
    The TCM determines whether the system is defective by monitoring the output speed sensor.

    DESCRIPTIONS OF MONITOR METHODS
    The status with the secondary pulley speed of 1,500 r/min or more and with the output shaft speed of 150 r/min or less continues for 10 seconds.
    When the output shaft speed has dropped abruptly from 730 r/min or more to 90 r/min or less, and then it keeps 90 r/min or less for 0.5 seconds continuously.

    MONITOR EXECUTION
    Transmission range: D, R or B

    MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR)
    Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
    P0705: Malfunction of transmission range switch
    P0791: Malfunction of secondary pulley speed sensor
    Sensor (The sensor below is determined to be normal)
    Transmission range switch
    Secondary pulley speed sensor

    DTC SET CONDITIONS
    Check Conditions
    Transmission range switch position: D, R or B.
    Voltage of battery: 10 volts or more.
    Voltage of battery: 16.5 volts or less.
    Judgment Criteria
    The status with the secondary pulley speed of 1,500 r/min or more and with the output shaft speed of less than 150 r/min continues for 10 seconds.
    The output speed has dropped abruptly from 730 r/min or more to 90 r/min or less. Then at least 0.5 seconds have passed with the reduced speed.

    OBD-II DRIVE CYCLE PATTERN
    The vehicle is driven for at least 20 seconds with the engine speed at 3,500 r/min or more.

    PROBABLE CAUSES
    Malfunction of output speed sensor
    Damaged wiring harness and connectors
    Malfunction of TCM



        __________________________________________

        click to view fuel log View my fuel log 2015 Mirage ES 1.2 manual: 50.0 mpg (US) ... 21.2 km/L ... 4.7 L/100 km ... 60.0 mpg (Imp)


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    Daox (11-22-2017),Fummins (11-22-2017),Top_Fuel (11-22-2017)

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