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  1. John Jefferson

    John Jefferson New Member

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    2002 VX Auto Supercharge L67

    Situation and symptoms

    After replacing the cas sensor (to solve DTC), the car won't crank (main issue).
    "serv error" is displayed on the dash.
    Instrument cluster lights up as (normal).
    MIL light is on but wont flash DTC when pins 5 and 6 are bridged.
    Anti theft light turn off when key is turned to reds (as normal).
    The fuel pumps and relays can be heard after turning to reds for the first time after the battery has been disconnected for awhile, afterwards no more sounds are made turning the key back and forth (until the battery is again disconnected).


    What has been done in attempt to fix and what happened:

    Battery has been fully charged, definitely works. Voltage is 14.2 and can be used to start a HQ and VE.

    Temporarily reconnected the original cas, no symptoms changed.

    Connected a gscan2 (not a tech2). Here where it gets tricky. If the battery is disconnected and reconnected after a little bit (presumably resetting the bcm) and the key isn't turned to red, the gscan recognises the BCM (and only the BCM). When the key is turned to reds, gscan loses connection and can not reestablish. (no connection to any module)

    But with the pcm disconnected, the bcm is initially recognised however when the key is turned to reds, while the BCM is still lost, the ABS, SRS and anti theft can now be read when the connection is reestablished.

    I have followed all (at least most) respective diagnostic charts (but with a gscan 2 instead of tech2).

    The following have been checked

    Fuses (visual and continuity) and audio-inspection operation of relays in both sets (the engine bay and beneath the instrument cluster).
    Circuit 1221 (serial data) between DTC, PCM and BCM.
    Earths for BCM, PCM and DTC connector.
    Ignition and battery feeds for PCM.

    I would like to add that I can only have the gscan2 for an afternoon at a time (has already been returned).

    Thats all I have to say, I would much appreciate any help or ideas.
     
  2. Brysha89

    Brysha89 Active Member

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    if everything worked before replacing the cas put old one back in fully and bridge pins 5&6 with the ignition on and see what codes thrown, if its only says the code for cas then you have brought an inferior sensor that wont crank engine and could be doing the other stuff to the dash i.e no flash when bridging pins, Gscan2 and all other scan tools don't relay work on the ecotec's tech2 or bridging pins 5&6 is best for them.
     
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  3. Not_An_Abba_Fan

    Not_An_Abba_Fan Exhaust Guru

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    The CAS will only read the signal from the harmonic balancer, it will work or it won't. It doesn't affect the car in any other way. If it is faulty, the car will still crank but won't fire because the ECU won't see the signal.

    It may be just coincidence but I would check that the key is making contact with the ring on the ignition. The security light goes out with the key on so that may not be the issue.

    You may have knocked a plug loose changing the CAS as well, pull the plug from the ABS module, give it a clean and plug it back in. See how that goes.
     
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  4. John Jefferson

    John Jefferson New Member

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    Forgot to mention, slip ring and key contact is fine, when i was able to connect to the bcm, it did recognise the key, just couldn't keep it connected long enough to see if passive mode turned off when the key was turned. (also checked continuity from the key slip ring contact to where the cable contact plugs inside the steering column).

    I also read somewhere trying to start it with the ABS disconnected. Tried it to no avail but ill give it a clean and see how that goes. (that was a week or two ago)
     
  5. John Jefferson

    John Jefferson New Member

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    Im trying to find a tech2 somewhere to borrow (Brisbane Ipswich area).
    Full swapping out the CAS is quiet the arduous task (balancer off) so its something I would prefer to be done after all other potential solutions have failed (even if it may the issue). I have however tried with original cas hanging off its harness (so plugged in just not mounted). Any additional ideas would be great to attempt before full swapping the original would be great :D.
     
  6. lout

    lout Well-Known Member

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  7. John Jefferson

    John Jefferson New Member

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    I can see F31 referenced as fuse(Engine Control / BCM Fuse) in position no. 24 but the engine bay fuse compare (according to the service info manual). Under the dash, the fuses positions are numbered up to 27.

    Is that the right fuse (despite being in the engine bay fuse compartment) or is definitely in the instrument cluster compartment? If so, what would it be referred to as?
     
  8. lout

    lout Well-Known Member

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    fuse 31 under bonnet and fuse 14 under dash
     

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