Checking your Computer for Faults (VN - VP)

[Darren]

1. Remove the kick panel on the passenger side below the glove box.
2. Grab a paper clip and bridge out the 'white' and 'black wire on the ALDL (Assembly Line Diagnostic Link) which can be found generally on the right hand side of the ECM (Electronic Control Module)or hanging down below it.
3. Jump into the drivers seat and turn the key twice (so lights are up on the instrument cluster).
4. If you bridged out the correct wires you will hear the electronic fan cut in and the 'Check Engine Lamp' will be flashing.
5. The flashes are divided into 2 groups with roughly a second between each. You can read the flashes as follows:
   
   The first series of flashes is tens, so for example lets say the first flash simply flashes once, this means the code is 10. After the pause (~1 second) a second series of flashes will appear, if this number is 2, the code it is spitting out is 12 which means everything is fine.
   
   
6. Another example just so your sure
   
   The first series of flashes you count is 4 meaning 40, the second series of flashes is 3. Adding the 40 and the 3 will give you a code of 43 which means the Knock sensor circuit is experiencing problems.
   
   
7. Each code the computer picks up is repeated three times with ~3 second pause between, so its wise to sit there to make sure there isn't any problems it has picked up.
   
8. Once you are finished turn off your ignition, remove the paper and replace the kick panel. It is important to note not to drive the car around while have wires are bridged as this will prevent new codes from being logged.
   
   Any questions or queries please feel to contact me at anytime.
   
   Checking the computer for codes is used in conjunction with the computer Fault Codes located here
   

[Darren]

I've had a couple of requests recenly to grab some photo's of where you bridge out the two connections in Step 2 so here they are:

VN Holden Commodore Diagnostic Connector Picture 1
VN Holden Commodore Diagnostic Connector Picture 2

Hopefully this clears it up.


Cheers
Darren

[BigMike]

Will this work for a VT Series 1?

[clixanup]

Will this work for a VT Series 1?

No, their systems are entirely different.

You can, however, hold down the "mode" and "set" buttons on the trip computer while starting the engine to get heaps of useless info. On VY they changed this to mode & up.

To extract trouble codes from the PCM on VT onwards you need a Tech2 or similar device.

[vl rb30]

hi there thanks 4 your help i done the teast when i turned the reds on i got 1 flash than another flashh then 2 flashes to start with then it started all over again and 1 flash started 3 seconds later 2 flashes went and then it just repeated itself so all the codes are 12 thats fine but during the test my thermo fan stayed on and if there is no fault codes how come my engine light comes on every know and then thanks buddy

[krawczuk]

I've had a couple of requests recenly to grab some photo's of where you bridge out the two connections in Step 2 so here they are:

VN Holden Commodore Diagnostic Connector Picture 1
VN Holden Commodore Diagnostic Connector Picture 2

Hopefully this clears it up.


Cheers
Darren

hi, that picture is NOT one af the aldl connector .
the aldl connector is a square connector with a notch in it.
mark k

[bacon-n-eggs]

Ive linked up the white and black connectors, with the wires definately making contact with the metal within the connector however when i turn the key to II it still doesnt do anything? It says if it doesnt then i havent bridged it correctly but how is that so when it is a clear circuit?

Fanx for the help peeps

[Jaym]

Ive linked up the white and black connectors, with the wires definately making contact with the metal within the connector however when i turn the key to II it still doesnt do anything? It says if it doesnt then i havent bridged it correctly but how is that so when it is a clear circuit?

Fanx for the help peeps

Mate you are using the wrong plug the in the pic is WRONG its the smallier one next to it

[MarzVP]

new pics added hope that clears it up for people.

[beefcream]

very handy.. thanks a lot

[2greedy]

well i just done mine and woohoo the good old number 12

[Inquisitor]

Hey guys,

Thanks fort this - helped a lot when diagnosing

One thing to note though - my ECU was stuffed - and the engine lamp would stay on, and not flash any codes at all. Replaced it, and all was good

[SweetWagon]

great how-to, checked mine today and got a code 12 Just need to replae thermostat as it runs cold.

Cheers

[m3taL]

Yay! now i can go see why my biatch died twice on the way home tonight... Just Stalled then turned over for 30/40 sec then started Like a shitty old 202 (holding the pedal to the floor)... hoping its not a frikken fuel pump....

[Jo3_Blo]

Cool! Do all Vn's and VP's have comps?

[walesy]

is it the same for the 5ltr? coz i had the problem that someone else had where it keeps cutting out then takes a bit of crankin 4 it to start again

[padrickz88]

hey nice tutorial...... i was just thinking about doing this tomorrow but has any body thought about cutting the white and black wire's then adding a wire 2 each then running it to a switch? and sticking the button whereever you want? save you taking the kickpad off all the tym and all u'll have to do is flick the switch.... would it work? i dont see why it wouldnt.. neways keep up the good work and thanks alot

[nevj]

Sure, just make it one of those retunable/ springloaded switches that you have to keep your finger on. You don't want to accidently leave the switch in the closed position, not sure of possible effects but new codes won't register if switch is in closed position.

[14secvp]

Not the best idea putting a switch on it cos you need to bridge the connection with as little resistance as possible ie a paperclip the resistance in a length or wire might be to high.There are three different modes you can put the ecu into with this same connection but with a resistor for using diagnostic software.When in aldl mode the light flashes fast.If you think the paperclip is good get winaldl which is free and a laptop then youll be away

[Bairdy215]

thanks. i just checked my vn berlina and got 22. now i gotta work out hoe to fix it.

[14secvp]

Code 22 throttle position sensor I think if I remember rightly

[dirk]

great advice. Now I know my idle problem isnt ECM or sensor related (?) as I got a 12.
Wondered if anyone has used limp home mode/ Read it needs a 3.6 o resistor between ground and diagnostic ie paper clip link. Is there a wire of particular length to do this, does it need a wire with a resistor made up.cheers

[14secvp]

The computer can lie to you sometimes my mates vn never had any codes but was coughing and splutering aldl showed low coolant temp replaced coolant temp sensor still the same put new ecu in goes better than it has for years no problems.What sort of idle problems have you got mate.

[dirk]

The computer can lie to you sometimes my mates vn never had any codes but was coughing and splutering aldl showed low coolant temp replaced coolant temp sensor still the same put new ecu in goes better than it has for years no problems.What sort of idle problems have you got mate.

Idle is rough - like its missing but intermittently across several cylinders. The plugs are all clean/perfect grey, its very economical on gas, and has heaps of power etc. It does have a sagging RH engine mount which makes it seem worse, but you can feel it when reving up under bonnet by moving throttle.

[pr0n]

everytime i check mine it comes up with 1 flash then a short pause then 2 flashes, so number 12, why would the light come on if it was fine? how do i remove it now?