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Thread: TPS Error / P0121 Help?

  1. #1
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    TPS Error / P0121 Help?

    Hey all, I have a 2011 MK6 Golf 2.0 TDI and need help if anybody can?

    So I have the Emissions Control/Engine Management light on. I've taken it to the garage and they plugged it into a VCDS i'm assuming. They didn't give me the full details, however they did write down the following;

    P0121 - Throttle Position Sensor, implausible signal, short to plus.

    They told me that the light is on due to the TPS, and said that to fix it, I should replace the accelerator pedal. I've been looking around the web and most others are saying that the TPS itself should be replaced rather than just the accelerator pedal? Is there any way i could check this?

    I've also another issue with the start/stop. When I put the car in neutral and remove my foot from the clutch pedal, so that the engine turns off at traffic lights, a message pops up saying "Engine fault - take to workshop" and the Glow Plug light begins blinking. The car also won't start when i put the clutch back in. I have to manually restart the car. However this doesn't seem to affect performance, or go into limp mode.

    I have told the garage about this, but they did not come back with any information regarding the issue, and they said the only code stored is P0121

  2. #2
    Administrator Crasher's Avatar
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    Apr 2006
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    A common fault, the pedal is a complete unit that is virtually just clipped to the floor and it gets wet.
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  4. #3
    Administrator Keithuk's Avatar
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    First posts normally go in introductions else you could get a free fix and we never see you again!!!

    VAG Error Code: 16505/5286/000289
    EOBD II Error Code: P0121

    Fault Location:
    Throttle Position Sensor (G69) - Implausible Signal

    Possible Cause:
    Malfunction Indicator Lamp (MIL)(K83) active.
    Poor engine performance.

    Accelerator cable adjustment.
    Throttle position sensor (G69).
    Wiring/Connector(s)/Wiring Harness issue.
    Failed Throttle Body.
    Failed Engine Control Module (ECM).

    Possible Solutions:
    Check/Replace all faulty Wiring/Connector(s).
    Read Measuring Value Blocks (MVB).
    Throttle Position Sensor 1 - Throttle Position Sensor 2 > 6.30%.
    Actual Throttle Position Sensor 1 calculated value > Throttle Position Sensor 2 calculated value.
    Throttle Position Sensor 1 calculated value > 9.00%.
    Test wiring as per Factory Repair Manual

    Special Notes:
    For some vehicles, there may be a Technical Product Information (TPI) with instructions on replacing the terminals for the throttle body.
    Some Engine Control Module (ECM)s may have a firmware update to address this issue during cold weather.
    The component identifier Throttle Position Sensor (G69) may be Angle Sensor 1 for Throttle Actuator (G187) per the wiring diagrams for the vehicle in question.

    When is the code detected?:
    Malfunction is detected when an excessively low or high voltage from the sensor is sent to Engine Control Module (ECM).

    The throttle position sensor responds to the accelerator pedal movement. This sensor is a kind of potentiometer which transforms the throttle position into output voltage, and emits the voltage signal to the Engine Control Module (ECM). In addition, the sensor detects the opening and closing speed of the throttle valve and feeds the voltage signal to the Engine Control Module (ECM).

    Idle position of the throttle valve is determined by the Engine Control Module (ECM) receiving the signal from the throttle position sensor. This sensor controls engine operation such as fuel cut. On the other hand, the Wide open and closed throttle position switch, which is built into the throttle position sensor unit, is not used for engine control.

    As taken from my new EOBD II Fault Codes Software
    2010 Golf GTD (170) CBBB, 5 Door, Shadow Blue (P6/D5Q), Transmission Code: KXZ, Flat Tyre Indicator, Basic Protection Pack + VCDS.

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  6. #4
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    @Crasher Thanks for the reply. Yeah it doesn't seem too great, especially with the UK weather. I've ordered a new pedal, guess i'll see how it goes.
    2011 Golf 2.0 TDI-CR

  7. #5
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    May 2019
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    @Keithuk Apologies for that, I didn't realise Appreciate the detailed information, can see that it could be one of many problems, which isn't too good. I'll see how the new pedal goes else I guess it'll be going back into the garage to be looked at again.
    2011 Golf 2.0 TDI-CR

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