VZ ecu doesnt communicate to tech2

[SoullessShadow]

I generally try to avoid working on these pos but it's a mates car so here I am...

It's a VZ has all the usually signs of a failing ecu/pim
- low fuel warning
- doesn't crank off the key but does when relay is jumped

The tech2 cant communicate to the ecu at all like the module isnt present at all.

"Check CAN-bus components:
Mandatory ECU is missing"

I had him get another ecu and that one does exactly the same thing. So I've either got 2 bad ecu which is quite possible or there is some sort of wiring problem with the car itself.

Has anyone had a similar problem with not been able to communicate at all with the ecu?
I'm aware even once I get that part to work unlinking and then linking another ecu isnt a straight forward process...

But any direction to look in before I get to far into it. Did basic checks. Does ecu have power ground etc

[The1]

Do the connectors look clean and not corroded, fuses all good?

[ejukated]

Probably worth asking - do you have the CANDI module connected?

[SoullessShadow]

Yeah pins look nice and clean and straight on both ecus.

Candi module is connected and can find every other module that's installed in the car except engine and PIM

[The1]

can you connect to PIM if ecu isn't connected?

[mattyjf01]

After jumping the relay and car is running can you connect?

[SoullessShadow]

I didnt try to connect to the PIM without the ecu plugged in. Or test for power and ground at it either. That gives me something else to check next time I'm with the car

I should add the car does not run. Has abs and airbag lights on and the speedo sometimes jumps up and down or stay over at 240kph with just the ign on..

[mattyjf01]

Strange one
Maybe try disconnecting the abs module?
my scanner cant communicate with pim unless bcm is connected