Software On ELM Street - OBD2 Software Development

[Tazzi]

I'll grab the snippit when I see it again.. see if we cant figure it out.

[Jayme]

ive got a double jumpered log of my VY ALDL + VPW at the same time with the same timestamps to see what is talking between the buses and when... I might have to do the same for my VZ, ALDL + CAN and see if I can find the anti theft packets and see whats actually sent.

[Tazzi]

The vehicle incorporates a theft deterrent system. After the ignition switch is turned to the ON position, and the
powertrain interface module (PIM) has authenticated the body control module (BCM), the PIM sends an encrypted
security code to the engine control module (ECM). The ECM compares the received security code with its own security
code, and if it is valid, the ECM enables the vehicle to be started.

Direct from the Holden docos.

wiringlayoutVZ.PNG

[Jayme]

so 2 things happen here.... the PIM authenticates the BCM... (what does that mean ?? checking VIN matches or does the PIM receive the actual code from the KEY via the BCM... or both ??)

then the PIM sends a code to the ECM to start.. so the ECM needs to be told what key the PIM will be sending and the BCM and PIM need to be told to like each other too....

[Tazzi]

Yeah I think "authenticate" means check they have the same vin. Since, the PIM stores the VIN in it like you said.

The docos say that you need to reprogram the VIN (which occurs over ALDL I think) which can be done using the tech2 under the PIM section (this is for both new and used PIMS) which needs to match the ECU VIN.

Then from there, you need to perform the "BCM Link to PCM/PIM" which links all three together once the PCM an PIM have the same VIN.

So the main thing there, is it says the PIM must have the correct VIN programmed in. So in the case or replacing an ECU.. the ECU VIN must be changed to the PIM's vin or vise versa. Once done, you do the bcm link procedure and all three will be happy chappys.

[Tazzi]

It also says:

When a PIM has been installed into a vehicle, it is security linked to the BCM and ECM. Once this linking has been performed, the PIM cannot be installed in any other vehicle, unless the security linking between the BCM and the ECM has been reset

And this is also done under the PIM heading in the tech2... Bugger.. I knew I should have picked up a PIM ages ago to reverse engineer that! haha

[Jayme]

ive got a VY ls1 pim you can have sitting on my shelf looking ugly

[Tazzi]

When performing the BCM link to ecm/pim.. the procedure on the tech2 is (if replacing PIM):

Prior to performing the linking procedure, obtain the security code and BCM security number. For further
information, refer to Vehicle Security Card.
2 Connect Tech 2 to the data link connector (DLC).
3 On Tech 2 select: Body / Powertrain Interface Module / Security / BCM Link to ECM / PIM.
4 When Tech 2 displays BCM Replaced, press the No soft key.
5 When Tech 2 displays PIM / ECM Replaced?, press the Yes soft key.
6 When Tech 2 displays Select Engine Type use the up and down arrow selection keys to select the appropriate
engine type and then press the Enter key.
7 When Tech 2 displays Please Select, use the up and down arrow selection keys to select PIM Replaced, and then
press the Enter key.
8 When Tech 2 displays BCM Security No., enter the BCM security number, press the Enter key.
9 When Tech 2 displays Turn Ignition Off!, turn the ignition switch off.
10 When Tech 2 displays Turn Ignition On, turn the ignition switch on.
11 When Tech 2 displays Enter Security Code, enter the security code and press the Enter key and then the Okay
soft key.
12 When Tech 2 displays Confirm Security Code, re-enter the security code, press the Enter key and then the Okay
soft key.
13 When Tech 2 displays Stop Engine – Turn Off Ignition, turn the ignition switch off.
14 When Tech 2 displays Turn Ignition On, turn the ignition switch on.
15 When Tech 2 displays Programming Successful, press the Confirm soft key to return to the Tech 2 Security
screen.

So.. you get a choice of what is being replaced..and go from there. If both PIM and ECU are to be replaced.. Id assume you would need to link the new ECU to the current PIM and BCM in car. Then "reset" the PIM security, install new PIM and link the PIM to ecu and bcm. (I think!)

[Tazzi]

ive got a VY ls1 pim you can have sitting on my shelf looking ugly

And Iv got a VY BCM and PCM here.. so might work out

But first..Just got to figure out how all three link up.. if they are all from different vehicles!!! lol. Looks like it needs to do them 1 at a time to link it to the original system.

[Jayme]

Its got your name on it! Lookout this pim has got a MAPLESS tune on it haha

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