Limp Mode (again) Plus many other issues...

Discussion in 'VW Mk4 Jetta, Golf, New Beetle, Passat TDI forum' started by Coach Pat, May 1, 2012.

  1. Coach Pat

    Coach Pat New Member

    May 1, 2012
    Golf TDI/2002
    150k miles, 43 mpg.
    2002 Golf TDI.
    List of fault codes::panic:
    P0671-674 Cyl. 1 thru 4 glow plug circuit
    P0128 COOLANT THERMOSTAT BELOW REGULATING TEMP (is that really a bad thing??)
    P1556 No DTC definition found.
    I've reviewed the VTN post. I will start there to address the limp mode issue. Question is this: Are any or all of the other faults related? P0671 thru 674 I believe may be a harness issue (as I was told from the dealer).
    Old Blue has 150,000 + miles and still averaging 43 mpg ~ 2.32 gal/100 miles.

    Any information is greatly appreciated.
  2. Keithuk

    Keithuk Super Moderator

    Aug 29, 2010
    2010 Golf GTD (170) CBBB
    Stoke on Trent, England
    Welcome to the forum. welcometomyturbodies

    VAG Error Code: 17055
    EOBD II Error Code: P0671

    Fault Location:
    Glow Plug Cylinder 1 (Q10) Circuit - Circuit malfunction

    Possible Cause:
    No Pre-Glow Period.
    Poor Cold Starting.

    Glow Plug Wiring faulty.
    Poor connection.
    Glow plug control module.
    Glow Plug faulty.
    Engine control module (ECM).

    Possible Solutions:
    Check Glow Plug Wiring.
    Check Glow Plug.

    Special Notes:
    See TDIClub Glow Plug 101

    VAG Error Code: 16786
    EOBD II Error Code: P0402

    Fault Location:
    Exhaust gas recirculation (EGR) system - Excessive flow detected

    Possible Cause:
    Malfunction Indicator Light (MIL) ON.
    Reduced Exhaust Gas Recirculation (EGR).
    Reduced Power Output/Engine running rough.
    Increased Emissions.

    Hose leak/blockage.
    Basic setting not carried out.
    Exhaust Gas Recirculation (EGR) Flow restricted/clogged.
    Exhaust Gas Recirculation (EGR) Valve stuck closed/leaking/faulty.
    Wiring and/or Connector(s) from/to Exhaust Gas Recirculation (EGR) Valve faulty.
    Exhaust Gas Recirculation (EGR) System faulty.

    Possible Solutions:
    Check/Clean Exhaust Gas Recirculation (EGR) System.
    Check/Replace Exhaust Gas Recirculation (EGR) Valve.
    Check Wiring and/or Connector(s) from/to Exhaust Gas Recirculation (EGR) Valve.

    VAG Error Code: 16512
    EOBD II Error Code: P0128

    Fault Location:
    Coolant thermostat - Coolant temperature below thermostat regulating temperature

    Possible Cause:
    Mechanical fault.

    VAG Error Code: 17964
    EOBD II Error Code: P1556

    Fault Location:
    Charge Pressure Control - Negative deviation

    Possible Cause:
    Reduced power output.
    Limp mode.

    Boost Pressure too Low.
    Hoses/Pipes incorrect connected, disconnected or leaking.
    Charger Pressure Control defective.
    Variable Nozzle Turbo (VNT) nozzles stuck.
    Solenoid Valve for Boost Pressure Control (N75) defective.

    Possible Solutions:
    Check Hoses/Pipes to/between Components.
    Check Solenoid Valve for Boost Pressure Control (N75).
    Check / Clean / Replace Charge Pressure Control.
    Check / Clean mechanism for variable nozzles.

    As taken from my
  3. Coach Pat

    Coach Pat New Member

    May 1, 2012
    Golf TDI/2002
    150k miles, 43 mpg.
    Thank you for the response.

    I tried PB on the VTN lever last night per the VTN guide. Unfortunately that was not the quick fix I was hoping it to be. Looks like I'll be under the hood this weekend.
    Thank you again for the guidance. I'll report back.

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