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  1. #1
    Join Date
    May 2018
    Location
    Woking, UK
    Posts
    159

    Default Gearbox actuator?

    Mysterious gear selection problem:

    Car sometimes wonít go into 1st, or reverse gear and stays resolutely in neutral. Initial thought is, of course itís the clutch actuator, but the car starts - no 3 lines on the dash. Iíve recently rebuilt the engine and so I checked and greased the clutch release lever where they wear through plus I replaced the actuator a year ago and it was all fully greased up, so I don't think it's that. I also replaced the engine loom so the wiring is perfect, no wiring issues. Iíve had the MB Star on there and done the clutch re-teach and biting point adjustment settings, all fine. There were one of two codes, P2022 (clutch system fault) and P202A (Gear cannot engage when clutch is closed), and also P205F (implausible signals from steering wheel gear shift) before I started.

    The first two look like perhaps the gear shift motor is knackered? The last one seems strange although sometime changing down with the paddles didnít work. The only other clue I've noticed is that Iíve had the engine almost stop when coming to a halt a couple of times, as if the clutch wasnít disengaging (bit like when you jump into a manual car after you have been driving an auto and you forget to press the clutch!

    Anybody suggest the next course of action? (thanks!)

  2. #2
    Join Date
    Jul 2005
    Location
    over here
    Posts
    13,849

    Default Re: Gearbox actuator?

    Have you checked 2 and 3 sensor ?

    http://www.fq101.co.uk/how-to-guides...x-sensors.html
    fq101.co.uk

  3. #3
    Join Date
    May 2018
    Location
    Woking, UK
    Posts
    159

    Default Gearbox actuator?

    Not checked those. Iíve read (on here I think, Tolson perhaps?) that the position sensor isnít required except for initial setup. And the gearbox speed sensor Iím not so sure about... I suppose it could prevent the clutch disengaging if the car thinks itís moving rather than coming to a stop? But would the speed sensor stop the gearbox going into 1st or reverse from standstill? Plus thereís nothing in the log against either. But would there be a fault code for either? How often do the gearbox position and speed sensor fail?


    Sent from my iPhone using Tapatalk

  4. #4
    Join Date
    Jul 2005
    Location
    over here
    Posts
    13,849

    Default Re: Gearbox actuator?

    Thereís no Ďerrorí signal from any sensor, only if the software is Ďcleverí (i.e. programmed to spot out of bounds replies or just Ďweirdí replies) enough to spot a Ďfunnyí answer from a sensor is anything reported.

    Moral of the story is donít rely on the error log to point you in the right direction.
    Go over your previous work and donít assume something is ok just cos you worked on it recently.
    fq101.co.uk

  5. #5

    Default Re: Gearbox actuator?

    Try re-calibrate the steering wheel.
    Also check the teeths of gearing inside the clutch actuator.
    Remove electric motor from the clutch actuator and see if the first 5 teeths are okay.

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