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EGT Sensor again.

Discussion in 'A3/S3 Forum (8L Chassis)' started by sean_s3, Oct 26, 2011.

  1. sean_s3
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    sean_s3 Member

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    [Oct 26, 2011]
    It would appear that my long run of trouble free motoring in over. I had a full service carried out on the car last week and out of curiosity I did some code reading at the weekend to find that the EGT sensor fault is showing again.


    17868 Exhaust gas temp sensor 1 (G235) Implausible signal . P1455 - 35 - 10 Intermittent.



    I had this sensor replacing less that 2 years ago , can these things fail so quickly ?? Or could it be possible that something else is causing it to fail ?? This fault is the only one registered on the ecu so it doesnt look like its a knock on effect of another problem somewhere else.

    Any thought would be appreciated.

    Cheers.
    Sean.
    #1
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  3. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Oct 26, 2011]
    Wiring fault? I would be tempted to rewire back to the ECU tbh... I had an intermittent knock sensor issue that disappeared when I re wired it directly to the ECU... worth a punt else you could be replacing 180 quids worth of sensor for nowt...

    <tuffty/>
    #2
  4. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Oct 26, 2011]
    Given its "implausible signal" rather than a circuit fault, it could be caused by a failing MAF or dodgy lambda sensor.

    The engine ECU calculates a "virtual" EGT as well as taking a measurement from the probe, and if they differ too much the ECU will flag the above code.

    IE engine runs lean due to faulty sensor, lean-ness causes high EGT, ECU doesnt expect high EGT because load isnt high enough, pops fault code.
    #3
  5. sean_s3
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    sean_s3 Member

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    [Oct 26, 2011]
    Thanks for the replies.

    @ Tuffty I dont know if I would be comfortable wiring it up to the ECU but I will take a look at the connection to make sure its actually in right, It may be that it has been knocked while it was in for servicing last week.

    @ Aragorn I did consider the MAF but that is a relatively new unit as well , probably around 2 1/2 years old. i think the lambda is the original. Would unplugging the MAF help in checking out this theory ?

    For the moment in time I have cleared the fault and when driven steady it doesnt come back , although 2 of the readiness tests still show as failed.

    Many thanks.
    Sean.
    #4
  6. aragorn
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    aragorn "Stick a V8 in it!" Staff Member Moderator VCDS Map User

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    [Oct 26, 2011]
    which readiness tests have failed?

    Unplugging the MAF will just put the car into limp mode, so wont tell you much at all.

    Maybe check the fuel trims in block 32, if they're far out it could help narrow it down to the lambda?
    #5
  7. sean_s3
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    sean_s3 Member

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    [Oct 26, 2011]
    The test for emissions and the catalytic converter had failed but they have passed since they were orinially reset at the weekend.
    Steady driving is doing the trick as the fault has not come back but I know once on full boost it will reappear.

    I dont have the full version on vagcom unfortunatly so any further logging would have to be carried out by my local independant in order to get to the bottom of the problem.

    Many thanks.
    Sean.
    #6
  8. sean_s3
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    sean_s3 Member

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    [Oct 28, 2011]
    Right I now have a registered version of VCDS lite so I am able to tap in to more measuring blocks. What blocks would be worth checking and under what conditions ?? While idling block 118 for the egt was pretty healthy around the 330 c mark which seems reasonable.

    Im not convinced the sensor is bad, looking on other forums such as the TT forum and seat cupra forum there are several posts mentioning other problems causing the fault such as poor earth, MAF , strangled TIP etc. Hopefully we can narrow it down to a few possible factors before I spend £200 again getting the sensor replaced.

    Cheers.
    Sean.
    #7
  9. sean_s3
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    sean_s3 Member

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    [Oct 30, 2011]
    I have done some logs tonight logging blocks 001, 031 and 015 , and then another log on blocks 002 , 112 and 115 .
    Please take a look and see what you think .

    Here is blocks 001 and 031


    [TABLE="width: 843"]


    Group A:
    '001



    Group B:
    '031





    RPM
    Temperature
    Lambda
    Bin. Bits

    Lambda Factor
    Lambda Factor



    TIME




    TIME




    Marker
    STAMP
    /min
    °C
    %

    STAMP
















    [TD="align: right"]764.8[/TD]
    [TD="align: right"]2160[/TD]
    [TD="align: right"]69[/TD]
    [TD="align: right"]-2.3[/TD]
    [TD="align: right"]1101000[/TD]
    [TD="align: right"]765.32[/TD]
    [TD="align: right"]0.992[/TD]
    [TD="align: right"]0.992[/TD]



    [TD="align: right"]766.12[/TD]
    [TD="align: right"]2240[/TD]
    [TD="align: right"]69[/TD]
    [TD="align: right"]0.8[/TD]
    [TD="align: right"]1101000[/TD]
    [TD="align: right"]766.61[/TD]
    [TD="align: right"]1.008[/TD]
    [TD="align: right"]0.992[/TD]



    [TD="align: right"]767.43[/TD]
    [TD="align: right"]2120[/TD]
    [TD="align: right"]69[/TD]
    [TD="align: right"]2.3[/TD]
    [TD="align: right"]1110100[/TD]
    [TD="align: right"]767.91[/TD]
    [TD="align: right"]1.367[/TD]
    [TD="align: right"]0.984[/TD]



    [TD="align: right"]768.72[/TD]
    [TD="align: right"]3480[/TD]
    [TD="align: right"]69[/TD]
    [TD="align: right"]0[/TD]
    [TD="align: right"]1100000[/TD]
    [TD="align: right"]769.14[/TD]
    [TD="align: right"]1.016[/TD]
    [TD="align: right"]0.992[/TD]



    [TD="align: right"]770.03[/TD]
    [TD="align: right"]3800[/TD]
    [TD="align: right"]69[/TD]
    [TD="align: right"]-8.6[/TD]
    [TD="align: right"]1101000[/TD]
    [TD="align: right"]770.43[/TD]
    [TD="align: right"]0.984[/TD]
    [TD="align: right"]0.961[/TD]



    [TD="align: right"]771.25[/TD]
    [TD="align: right"]4240[/TD]
    [TD="align: right"]69[/TD]
    [TD="align: right"]-1.6[/TD]
    [TD="align: right"]1101000[/TD]
    [TD="align: right"]771.75[/TD]
    [TD="align: right"]0.945[/TD]
    [TD="align: right"]0.953[/TD]



    [TD="align: right"]772.66[/TD]
    [TD="align: right"]4680[/TD]
    [TD="align: right"]69[/TD]
    [TD="align: right"]-2.3[/TD]
    [TD="align: right"]1101000[/TD]
    [TD="align: right"]773.15[/TD]
    [TD="align: right"]0.961[/TD]
    [TD="align: right"]0.953[/TD]



    [TD="align: right"]773.95[/TD]
    [TD="align: right"]5040[/TD]
    [TD="align: right"]69[/TD]
    [TD="align: right"]0[/TD]
    [TD="align: right"]1101000[/TD]
    [TD="align: right"]774.35[/TD]
    [TD="align: right"]0.961[/TD]
    [TD="align: right"]0.953[/TD]



    [TD="align: right"]775.26[/TD]
    [TD="align: right"]5200[/TD]
    [TD="align: right"]69[/TD]
    [TD="align: right"]-0.8[/TD]
    [TD="align: right"]1110100[/TD]
    [TD="align: right"]775.66[/TD]
    [TD="align: right"]0.836[/TD]
    [TD="align: right"]0.961[/TD]



    [TD="align: right"]776.67[/TD]
    [TD="align: right"]3280[/TD]
    [TD="align: right"]69[/TD]
    [TD="align: right"]0[/TD]
    [TD="align: right"]1110000[/TD]
    [TD="align: right"]777.07[/TD]
    [TD="align: right"]1.991[/TD]
    [TD="align: right"]1.047[/TD]



    [TD="align: right"]777.98[/TD]
    [TD="align: right"]2840[/TD]
    [TD="align: right"]69[/TD]
    [TD="align: right"]0[/TD]
    [TD="align: right"]1110000[/TD]
    [TD="align: right"]778.38[/TD]
    [TD="align: right"]1.991[/TD]
    [TD="align: right"]1.047[/TD]



    [TD="align: right"]779.39[/TD]
    [TD="align: right"]2400[/TD]
    [TD="align: right"]69[/TD]
    [TD="align: right"]0[/TD]
    [TD="align: right"]1110100[/TD]
    [TD="align: right"]779.79[/TD]
    [TD="align: right"]1.991[/TD]
    [TD="align: right"]1.047[/TD]



    [TD="align: right"]780.69[/TD]
    [TD="align: right"]2040[/TD]
    [TD="align: right"]70[/TD]
    [TD="align: right"]0[/TD]
    [TD="align: right"]1110100[/TD]
    [TD="align: right"]781.09[/TD]
    [TD="align: right"]1.991[/TD]
    [TD="align: right"]1.047[/TD]



    [TD="align: right"]781.9[/TD]
    [TD="align: right"]1680[/TD]
    [TD="align: right"]70[/TD]
    [TD="align: right"]0[/TD]
    [TD="align: right"]1110110[/TD]
    [TD="align: right"]782.3[/TD]
    [TD="align: right"]1.991[/TD]
    [TD="align: right"]1.047[/TD]



    [TD="align: right"]783.31[/TD]
    [TD="align: right"]1080[/TD]
    [TD="align: right"]70[/TD]
    [TD="align: right"]0[/TD]
    [TD="align: right"]1110110[/TD]
    [TD="align: right"]783.71[/TD]
    [TD="align: right"]1.991[/TD]
    [TD="align: right"]0.945[/TD]



    [TD="align: right"]784.51[/TD]
    [TD="align: right"]1720[/TD]
    [TD="align: right"]70[/TD]
    [TD="align: right"]0[/TD]
    [TD="align: right"]1100110[/TD]
    [TD="align: right"]784.93[/TD]
    [TD="align: right"]0.984[/TD]
    [TD="align: right"]0.945[/TD]

    [/TABLE]





    Here is blocks 002 , 115 and 112


    [TABLE="width: 974"]

    Group A:
    '002



    Group B:
    '115



    Group C:
    '112



    RPM
    Load
    Inj. On Time
    Mass Flow

    RPM
    Load
    Absolute Pres.
    Absolute Pres.

    Temperature
    Load

    TIME




    TIME




    TIME



    STAMP
    /min
    %
    ms
    g/s
    STAMP
    /min
    %
    mbar
    mbar
    STAMP
    °C
    %















    [TD="align: right"]927.48[/TD]
    [TD="align: right"]2040[/TD]
    [TD="align: right"]14.3[/TD]
    [TD="align: right"]1.7[/TD]
    [TD="align: right"]5.58[/TD]
    [TD="align: right"]926.56[/TD]
    [TD="align: right"]1280[/TD]
    [TD="align: right"]15[/TD]
    [TD="align: right"]1000[/TD]
    [TD="align: right"]1000[/TD]
    [TD="align: right"]926.98[/TD]
    [TD="align: right"]625[/TD]
    [TD="align: right"]0[/TD]

    [TD="align: right"]928.79[/TD]
    [TD="align: right"]2080[/TD]
    [TD="align: right"]30.1[/TD]
    [TD="align: right"]3.4[/TD]
    [TD="align: right"]13.86[/TD]
    [TD="align: right"]927.99[/TD]
    [TD="align: right"]2080[/TD]
    [TD="align: right"]14.3[/TD]
    [TD="align: right"]1000[/TD]
    [TD="align: right"]1000[/TD]
    [TD="align: right"]928.39[/TD]
    [TD="align: right"]640[/TD]
    [TD="align: right"]0[/TD]

    [TD="align: right"]930.19[/TD]
    [TD="align: right"]2160[/TD]
    [TD="align: right"]54.1[/TD]
    [TD="align: right"]5.1[/TD]
    [TD="align: right"]23.14[/TD]
    [TD="align: right"]929.28[/TD]
    [TD="align: right"]2120[/TD]
    [TD="align: right"]51.1[/TD]
    [TD="align: right"]1000[/TD]
    [TD="align: right"]1010[/TD]
    [TD="align: right"]929.68[/TD]
    [TD="align: right"]665[/TD]
    [TD="align: right"]0[/TD]

    [TD="align: right"]931.49[/TD]
    [TD="align: right"]2320[/TD]
    [TD="align: right"]56.4[/TD]
    [TD="align: right"]5.44[/TD]
    [TD="align: right"]25.53[/TD]
    [TD="align: right"]930.69[/TD]
    [TD="align: right"]2200[/TD]
    [TD="align: right"]55.6[/TD]
    [TD="align: right"]1000[/TD]
    [TD="align: right"]1070[/TD]
    [TD="align: right"]931.09[/TD]
    [TD="align: right"]690[/TD]
    [TD="align: right"]0[/TD]

    [TD="align: right"]932.8[/TD]
    [TD="align: right"]2720[/TD]
    [TD="align: right"]134.6[/TD]
    [TD="align: right"]12.58[/TD]
    [TD="align: right"]76.64[/TD]
    [TD="align: right"]932[/TD]
    [TD="align: right"]2440[/TD]
    [TD="align: right"]93.2[/TD]
    [TD="align: right"]1770[/TD]
    [TD="align: right"]1150[/TD]
    [TD="align: right"]932.4[/TD]
    [TD="align: right"]715[/TD]
    [TD="align: right"]0[/TD]

    [TD="align: right"]934.21[/TD]
    [TD="align: right"]3600[/TD]
    [TD="align: right"]191.7[/TD]
    [TD="align: right"]19.04[/TD]
    [TD="align: right"]132.33[/TD]
    [TD="align: right"]933.22[/TD]
    [TD="align: right"]2920[/TD]
    [TD="align: right"]166.2[/TD]
    [TD="align: right"]2510[/TD]
    [TD="align: right"]1930[/TD]
    [TD="align: right"]933.71[/TD]
    [TD="align: right"]750[/TD]
    [TD="align: right"]0[/TD]

    [TD="align: right"]935.62[/TD]
    [TD="align: right"]4440[/TD]
    [TD="align: right"]191.7[/TD]
    [TD="align: right"]17.68[/TD]
    [TD="align: right"]163.86[/TD]
    [TD="align: right"]934.62[/TD]
    [TD="align: right"]3840[/TD]
    [TD="align: right"]191.7[/TD]
    [TD="align: right"]2520[/TD]
    [TD="align: right"]2390[/TD]
    [TD="align: right"]935.12[/TD]
    [TD="align: right"]825[/TD]
    [TD="align: right"]0[/TD]

    [TD="align: right"]936.93[/TD]
    [TD="align: right"]5120[/TD]
    [TD="align: right"]182.7[/TD]
    [TD="align: right"]17.68[/TD]
    [TD="align: right"]178.22[/TD]
    [TD="align: right"]936.03[/TD]
    [TD="align: right"]4640[/TD]
    [TD="align: right"]191.7[/TD]
    [TD="align: right"]2420[/TD]
    [TD="align: right"]2250[/TD]
    [TD="align: right"]936.43[/TD]
    [TD="align: right"]900[/TD]
    [TD="align: right"]0[/TD]

    [TD="align: right"]938.24[/TD]
    [TD="align: right"]5760[/TD]
    [TD="align: right"]172.2[/TD]
    [TD="align: right"]22.1[/TD]
    [TD="align: right"]188.67[/TD]
    [TD="align: right"]937.44[/TD]
    [TD="align: right"]5400[/TD]
    [TD="align: right"]178.2[/TD]
    [TD="align: right"]2290[/TD]
    [TD="align: right"]2090[/TD]
    [TD="align: right"]937.84[/TD]
    [TD="align: right"]955[/TD]
    [TD="align: right"]22.4[/TD]

    [TD="align: right"]939.55[/TD]
    [TD="align: right"]6280[/TD]
    [TD="align: right"]159.4[/TD]
    [TD="align: right"]21.42[/TD]
    [TD="align: right"]187.14[/TD]
    [TD="align: right"]938.74[/TD]
    [TD="align: right"]6000[/TD]
    [TD="align: right"]170.7[/TD]
    [TD="align: right"]2190[/TD]
    [TD="align: right"]1990[/TD]
    [TD="align: right"]939.13[/TD]
    [TD="align: right"]1110[/TD]
    [TD="align: right"]40[/TD]

    [TD="align: right"]940.85[/TD]
    [TD="align: right"]4920[/TD]
    [TD="align: right"]180.5[/TD]
    [TD="align: right"]25.16[/TD]
    [TD="align: right"]191[/TD]
    [TD="align: right"]940.05[/TD]
    [TD="align: right"]6160[/TD]
    [TD="align: right"]65.4[/TD]
    [TD="align: right"]1000[/TD]
    [TD="align: right"]1790[/TD]
    [TD="align: right"]940.45[/TD]
    [TD="align: right"]1110[/TD]
    [TD="align: right"]40[/TD]

    [TD="align: right"]942.06[/TD]
    [TD="align: right"]5040[/TD]
    [TD="align: right"]125.6[/TD]
    [TD="align: right"]17[/TD]
    [TD="align: right"]95.08[/TD]
    [TD="align: right"]941.25[/TD]
    [TD="align: right"]5040[/TD]
    [TD="align: right"]185.7[/TD]
    [TD="align: right"]2310[/TD]
    [TD="align: right"]2260[/TD]
    [TD="align: right"]941.66[/TD]
    [TD="align: right"]1110[/TD]
    [TD="align: right"]29.8[/TD]

    [TD="align: right"]943.37[/TD]
    [TD="align: right"]4120[/TD]
    [TD="align: right"]163.9[/TD]
    [TD="align: right"]23.46[/TD]
    [TD="align: right"]145.5[/TD]
    [TD="align: right"]942.56[/TD]
    [TD="align: right"]4320[/TD]
    [TD="align: right"]12[/TD]
    [TD="align: right"]1000[/TD]
    [TD="align: right"]1210[/TD]
    [TD="align: right"]942.96[/TD]
    [TD="align: right"]1110[/TD]
    [TD="align: right"]25.1[/TD]

    [TD="align: right"]944.78[/TD]
    [TD="align: right"]3360[/TD]
    [TD="align: right"]59.4[/TD]
    [TD="align: right"]8.16[/TD]
    [TD="align: right"]36.81[/TD]
    [TD="align: right"]943.87[/TD]
    [TD="align: right"]3720[/TD]
    [TD="align: right"]12[/TD]
    [TD="align: right"]1000[/TD]
    [TD="align: right"]1360[/TD]
    [TD="align: right"]944.37[/TD]
    [TD="align: right"]1110[/TD]
    [TD="align: right"]20.4[/TD]

    [TD="align: right"]946.19[/TD]
    [TD="align: right"]3240[/TD]
    [TD="align: right"]12.8[/TD]
    [TD="align: right"]0[/TD]
    [TD="align: right"]6.94[/TD]
    [TD="align: right"]945.18[/TD]
    [TD="align: right"]3360[/TD]
    [TD="align: right"]14.3[/TD]
    [TD="align: right"]1000[/TD]
    [TD="align: right"]1190[/TD]
    [TD="align: right"]945.68[/TD]
    [TD="align: right"]1110[/TD]
    [TD="align: right"]20.4[/TD]

    [TD="align: right"]947.6[/TD]
    [TD="align: right"]3160[/TD]
    [TD="align: right"]12.8[/TD]
    [TD="align: right"]0[/TD]
    [TD="align: right"]7.83[/TD]
    [TD="align: right"]946.67[/TD]
    [TD="align: right"]3200[/TD]
    [TD="align: right"]12.8[/TD]
    [TD="align: right"]1000[/TD]
    [TD="align: right"]1040[/TD]
    [TD="align: right"]947.08[/TD]
    [TD="align: right"]1110[/TD]
    [TD="align: right"]19.6[/TD]

    [TD="align: right"]949[/TD]
    [TD="align: right"]3040[/TD]
    [TD="align: right"]12.8[/TD]
    [TD="align: right"]0[/TD]
    [TD="align: right"]7.78[/TD]
    [TD="align: right"]948.09[/TD]
    [TD="align: right"]3120[/TD]
    [TD="align: right"]12.8[/TD]
    [TD="align: right"]1000[/TD]
    [TD="align: right"]1030[/TD]
    [TD="align: right"]948.49[/TD]
    [TD="align: right"]1110[/TD]
    [TD="align: right"]18.8[/TD]

    [TD="align: right"]950.3[/TD]
    [TD="align: right"]2960[/TD]
    [TD="align: right"]34.6[/TD]
    [TD="align: right"]4.42[/TD]
    [TD="align: right"]20.06[/TD]
    [TD="align: right"]949.5[/TD]
    [TD="align: right"]3000[/TD]
    [TD="align: right"]12.8[/TD]
    [TD="align: right"]1000[/TD]
    [TD="align: right"]1030[/TD]
    [TD="align: right"]949.9[/TD]
    [TD="align: right"]1110[/TD]
    [TD="align: right"]18[/TD]
    [/TABLE]




    EGT 's went through the roof and at 955 c the readings bombed out completly.
    MAF reading look pretty weak peaking at 187 g/s @ 6280 rpm. I'm certain i've had just above 200 g/s on occasion.
    How does block 031 look ?

    Any thought would be greatly appreciated.
    Thanks.
    #8

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