Does anyone have a reference waveform for ALDL Communication lines?

[ConfusedKiwi]

Hi everyone.

I have a VX that won't communicate with either of my scan tools.

When I look at the DLC com lines the waveform only peaks at about half a volt and is a bit triangular. I know almost nothing about ALDL but was expecting something like 5 or 8 volts of amplitude.

Can anyone fill me in on what I should be looking for, or even better post a waveform of a known good one?

Cheers in advance.

 

[Lex]

Hi everyone.

I have a VX that won't communicate with either of my scan tools.

When I look at the DLC com lines the waveform only peaks at about half a volt and is a bit triangular. I know almost nothing about ALDL but was expecting something like 5 or 8 volts of amplitude.

Can anyone fill me in on what I should be looking for, or even better post a waveform of a known good one?

Cheers in advance.

Why not just tell us what your symtoms are?

 

[NORTI]

Why not just tell us what your symtoms are?

I think this is it https://forums.justcommodores.com.au/threads/vx-crazy-airbag-and-pre-tensioner-issues.298442/

 

[Lex]

I think this is it https://forums.justcommodores.com.au/threads/vx-crazy-airbag-and-pre-tensioner-issues.298442/

There are other things that can set of airbag light, but usually it is the clockspring.

 

[ConfusedKiwi]

Why not just tell us what your symtoms are?

That's me in the thread below. For this one the symptom is not being able to get the scanner to connect. If I can get my scanner to connect I can figure out all my other issues easily.

 

[ConfusedKiwi]

I think this is it https://forums.justcommodores.com.au/threads/vx-crazy-airbag-and-pre-tensioner-issues.298442/

Yip that's me. Just keen to get the scanner to connect to solve this issue but also I suspect the SRS light may stay lit if it can't communicate with other modules too. Just keen to get it properly sorted rather than half done if I can.

 

[Lex]

Yip that's me. Just keen to get the scanner to connect to solve this issue but also I suspect the SRS light may stay lit if it can't communicate with other modules too. Just keen to get it properly sorted rather than half done if I can.

If you have abs light on? That can turn the airbag ight on too.

If the alternator is cactus that can turn the airbag on too.

Basically they cummunicate on a comms line.

This is a job for @lout. He is auto elec. So may be able to help you out?

He also has a vx.

 

[ConfusedKiwi]

If you have abs light on? That can turn the airbag ight on too.

If the alternator is cactus that can turn the airbag on too.

Basically they cummunicate on a comms line.

This is a job for @lout. He is auto elec. So may be able to help you out?

He also has a vx.

Lout is a legend, he has been helping me heaps in the other thread.
No ABS light so we are good there but good thinking. Great point about the alternator, I will test that, but I am more expecting a module or connection as the signal is there but weak on the comms line.
I have some great leads from you guys so really looking forward to going back (probably Friday) and running some tests. Even just having the chance to talk through the problems has given me much better perspective (I sound like an advertisement for a shrink now!).
I will report back on my findings!

 

[Immortality]

Your best bet is to talk to @TazzI from Envious Customs as he deals with this stuff every day.

 

[ConfusedKiwi]

Your best bet is to talk to @TazzI from Envious Customs as he deals with this stuff every day.

Thanks heaps! I have some leads to follow now but if I get stuck I will chase him down!