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Thread: astra 1.7cdti design. eml light on,( no codes stored)

  1. #1
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    Default astra 1.7cdti design. eml light on,( no codes stored)

    Right question if the EML comes on for a time should a fault code be stored as not getting any codes stored
    Brought myself a cheapish code reader ( autolink al 419) but its not storing fault codes?
    the reader has a facility to store live data i think but looking at it means very little to me.
    The light problem is intermittent but usually comes on first thing when cold and car reaches about 45 mph and stays on for about 10secs then goes out, but can also come on when going up hills and then goes into limp mode.
    Any advice please ( hometune)
    Last edited by jerry2294; 27-03-14 at 18:39.

  2. #2
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    Ah, you see, you have not been taking my advice on cheap scanners!!! If you used Vaux-com (or Vauxhall's Tech 2 or 3) it would show present (stored and active) and intermittent fault codes.

    Loss of power going up hills is most often a clogged up or faulty EGR valve but if you connect your scanner and go for a drive up a hill, then when the light comes on or you lose power, take a snapshot of the live data if this is possible. The problem is that if the EGR valve is faulty, then the DPF (if fitted) will not be cleaned and the problem goes round and round getting worse.

  3. #3
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    Smile

    Thanks for reply back hometune, problem you will find that for most DIY owners who want to avoid the big garages and who struggle with bills on a daily basis they cant afford the good scanners/ software so op for cheaper brands to get the best they can with what money they can afford.
    So you are 100% right but for one of those items unless like yourself doing daily jobs then its completely out of reach for me.
    Before i went to buy one i did take it to a small garage who didn't charge me and they couldn't find any codes, but again they didn't have the high end specs of equipment. So to close its finding a place who will not rip you off and also not charge stealer fee's......

    ps: This is not a rant from me as i do find all your feedback and input highly sort and correct so thanks for the feedback and keep it coming......

    Update with testing on the scanner, pending code of p0234 came up which gave me a few options ie: boost pressure sensor, faulty knock sensor, turbo problems....( hometune)
    Last edited by jerry2294; 30-03-14 at 12:48.

  4. #4
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    first place to start is to clean out the egr valve and associated pipework, cause of many a problem on a diesel engine.
    Worth taking a look at all other engine hoses too including turbo intercooler hoses for splits etc.

  5. #5
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    Agree with Pantera. There are 3 meanings for this code in this engine - could do with the engine code Z17DTL or Z17DTH or Z17DTJ or Z17DTR etc etc
    P0234 - boost pressure control malfunction
    P0234 - boost pressure control deviation positive (overboost)
    P0234 - boost pressure control deviation negative (underboost)

    These engines coke up very easily and can cause fault codes related to boost. Cleaning out the EGR valve and stainless pipe (at both ends), would be my first step. Any failure of the EGR system will cause boost problems as the air mass will be incorrect. It also causes failure of the DPF to regenerate so the exhaust gas soot builds up and up.
    Then check the EGR valve on a hot idling engine: when operating a reading between 40-70% (Z17DTH engine code) and when floored it will go off the scale.
    Check the boost sensor reading at idle and hot: 90-120 kPa (approx 1,000 mbar) and when floored will shoot up somewhere around 200 kPa (2,000 mbar).
    If the boost does go up when demanded and the EGR valve is reading within limits, then could be a sticking turbo due to carbon - either over or under boost. Some diesel specialists offer a cleaning service for this.
    If you have the Z17DTH you need to check the air intake actuator is working - this allows more air into the engine when under load.

  6. #6
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    Thanks pantera and hometune for you good comments.
    had this as follows on scanner: P0234 TURBO CHARGER OVERBOOST CONDITION.
    Also the engine is the Z17DTH. ( How would l know if my car has the DPF)
    Trouble is that l find it very awkward telling a mechanic what to do as l know alot of them use just codes and not to bothered about replacing items until they find the fault as the customer will pay?
    the big answer is finding a good garage as even the steelers have a good reputation to replace parts rather than a good clean of items/ parts like you have both said. to close all the above advice from yourselves is a tad above my understanding but l can understand but cant put what you say into practice myself, only a garage can do these checks for me.
    Last edited by jerry2294; 31-03-14 at 20:14.

  7. #7
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    P0234 - overboost means the vanes in the turbo are prone to sticking due to carbon build up. Maybe you could try something like this before going to a garage? I haven't used it myself so don't know if it works: http://www.ebay.co.uk/itm/Innotec-Di...-/220934225460

    This video is by one of the top diagnostic family (Massey) in the country so if they say something works, then it does: http://www.youtube.com/watch?v=Z7k5yE1FAJs

  8. #8
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    Thanks hometune will look into this and will update you with any news soon.....
    got snap shot of some date it stored not sure what it means. did not store codes but stored on pending codes.
    numbers of DTCs 0
    Calculated Load Value(%)72.2
    Engine Coolant Temperature(C)49
    Intake Manifold Absolute Pressure(kPa)108.0
    Engine RPM(rpm) 1724
    Vehicle Speed Sensor(km/h)75
    Intake Air Temperature(C)14
    Air Flow Rate from Mass Air Flow Sensor(g/s)30.22
    Absolute Throttle Position(%)12.2
    OBD requirements to which vehicle is designedEOBD
    Distance Travelled While MIL is Activated(Km)0
    Fuel Rail Pressure(kPa)79210
    Last edited by jerry2294; 01-04-14 at 23:16.

  9. #9
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    just a quick question is the boost control solenoid the same as the boost pressure sensor or are they both different and if so what part do they play......
    thanks again....

  10. #10
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    Im no expert on your particular engine but the boost sensor is probably the map sensor in the inlet manifold and the control solenoid would probably be the wastegate control solenoid so not the same item.
    As has already been said cleaning cures 90% of problems.

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