Ben Newell Posted June 13, 2014 Report Share Posted June 13, 2014 Hi, I'm after some assistance with a G4 Extreme ECU.  It's doing some strange things with outputs, ie injector tick when not running, aux outputs staying live when the key goes off, fuel pumps staying on when the key's switched off etc.  I've seen the wiring diagrams and have it wired in correctly with a main relay switching ecu power and power to trigger the fuel + spark relays, but still to no avail. I've taken measurements from the output pins on the ECU and have some rather strange results.  IE I'm getting +12v from aux channels! Could someone take a look at the below readings please, I'm assuming there's a blown power transistor somewhere. PORT A ====== Pin 1 +0.48v 2 +0.43v 3 +0.43v 4 +0.44v 5 +14v (input) 6 +8.03v 7 0v 8 0v 9 0v ==10 0v 11 0v 12 0v 13 0v 14 0v 15 +5v 16 +5v 17 0v ==18 +12.97v 19 +12.95v 20 +12.94v 21 +12.94v 22 0v 23 0v 24 0v 25 0v (grounded for test) ==26 0v 27 +12.59v 28 0v 29 +12.59v 30 0v 31 0v 32 +5v 33 0v 34 0v  PORTB ===== Pin 1 +0.74v 2 +0.68v 3 +0.68v 4 +0.68v 5 +14v (input) 6 +5.03v 7 +5.02v 8 0v 9 0v ==10 +7.3v 11 +7.3v 12 0v 13 0v 14 0v 15 0v 16 0v 17 0v ==18 +14.00v 19 0v 20 +10.66v 21 0v 22 0v 23 0v 24 0v 25 0v ==26 +14.00v 27 +12.59v 28 0v 29 0v 30 0v 31 0v 32 0v 33 0v 34 0v  I'll attach the PCL shortly. Thanks Ben Quote Link to comment Share on other sites More sharing options...
Ben Newell Posted June 13, 2014 Author Report Share Posted June 13, 2014 and after a factory reset: PORT A ====== Pin 1 +0.73v 2 +0.73v 3 +0.73v 4 +0.73v 5 +14v (input) 6 +8.03v 7 0v 8 0v 9 0v ==10 0v 11 0v 12 0v 13 0v 14 0v 15 +5v 16 +5v 17 0v ==18 +12.97v 19 +12.95v 20 +12.94v 21 +12.94v 22 0v 23 0v 24 0v 25 0v (grounded for test) ==26 0v 27 +12.59v 28 0v 29 +12.59v 30 0v 31 0v 32 +5v 33 0v 34 0v  PORTB ===== Pin 1 +0.74v 2 +0.68v 3 +0.68v 4 +0.68v 5 +14v (input) 6 +5.03v 7 +5.02v 8 0v 9 0v ==10 +7.3v 11 +7.3v 12 0v 13 0v 14 0v 15 0v 16 0v 17 0v ==18 +14.00v 19 0v 20 +10.66v 21 0v 22 0v 23 0v 24 0v 25 0v ==26 +14.00v 27 +12.59v 28 0v 29 0v 30 0v 31 0v 32 0v 33 0v 34 0v Quote Link to comment Share on other sites More sharing options...
Adamw Posted June 15, 2014 Report Share Posted June 15, 2014 It sounds very much like you have 12v back feeding through one of your aux outs. Have you tried disconnecting all aux out pins? Quote Link to comment Share on other sites More sharing options...
Ben Newell Posted June 15, 2014 Author Report Share Posted June 15, 2014 I thought this actually, so then removed the ecu from the car and powered it up on the bench, onto three wires connected, the two +14v and a ground. The readings I took were from the bench with nothing else connected. Goosed ECU? Thanks Ben Quote Link to comment Share on other sites More sharing options...
Simon Posted June 16, 2014 Report Share Posted June 16, 2014 This could well be the case as aux 5,6,7,8 can highside drive and if the drive is set to off will read 12V Sounds very much like you have some back feeding issues in the car. Also if you have a fuse on the ECU supply check this has not blown. Quote Link to comment Share on other sites More sharing options...
Ben Newell Posted June 17, 2014 Author Report Share Posted June 17, 2014 Hi Simon I don't see how there could possibly be any back feeding issues considering there were only three wires connected when I performed the test, the two +14v and one ground pin. All of the other readings were taken between the respective isolated pins and ground using a multimeter. Do you have a list of what the readings per pin should be on a fully working unit? The car still starts and runs but does really weird things with it's aux outputs. With my MS3 connected - it behaves perfectly. Thanks Ben Quote Link to comment Share on other sites More sharing options...
Simon Posted June 17, 2014 Report Share Posted June 17, 2014 The voltages you are seeing there I would consider totally normal. To test the Aux outputs you are much better to work through each one and use the test on function. And monitior what they do with a load attached. What you are seeing when the key is turned off is a powered ECU through a back feed. If wired correctly the drives will not be able to control any devices as they all should have lost they 12V supply so even if the ECU was to ground the drive they will not turn on. Quote Link to comment Share on other sites More sharing options...
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