Auto electrical guys - OBD2 Q

[visor_down]

Anyone got much experience of OBD2 on Opel/vauxhall?
Trying to find out why diag kit won't power up on Vauxhall Astra H Mk5 2006 Z17DTH
Have battery voltage on pin 16 and ground /signal ground on 4 & 5 so don't know why several scanners won't power up on it. Only thing that will work is opcom, but would prefer to be able to use one of the standalone bits of kit rather than laptop 'n' all.
Any one come across this or have any idea why they wouldn't power up (all work fine on other motors)
Cheers

 

[hotponyshoes]

Mechanical damage on the cars connector?
Maybe the Opcom cable has slightly bigger pins and is making a connection?

Seen plenty of readers that wont work on one car or another but they all power on when plugged in to anything.

Another thing to check is the battery voltage if the car has been stood up for a while?

 

[Ruffian]

Is pin 16 battery voltage on permanent live or ignition live?

Have has similar to said above the pins not making good enough contact.

 

[hotponyshoes]

I think part of the obd2 spec is for pin 16 to be permanently live from the battery?
I think it might be pin 1 that the manufacturers can decide to use as a switched live for their own diagnostic interfaces (to check key working etc)

 

[visor_down]

Cars connector is ok, it's one of more protected ones tbh, just compared and both have the same thickness of pins.
It's been on a maintainer 12.7 during testing
Yeah it's odd I could understand no Comms, but theres just no sign of life

 

[visor_down]

Is pin 16 battery voltage on permanent live or ignition live?

Have has similar to said above the pins not making good enough contact.

Permanent live

 

[sako243]

Do the grounds on the connector buzz through to ground?

 

[visor_down]

Do the grounds on the connector buzz through to ground?

Yes they do, both ground ok

 

[Kayos]

Astras can be a pain, what diag are you using?

You are right on the CAN changeover years for that model so you might have full or half

 

[visor_down]

Astras can be a pain, what diag are you using?

You are right on the CAN changeover years for that model so you might have full or half

autel, foxwell and a generic one. As I say opcom works fine, it's just I'd rather use the standalone kit and it doesn't make sense that standalone stuff won't power up off it?!

 

[hotponyshoes]

The autel should definitely power on as soon as its connected to any car so i reckon the car end must be the issue.
Have you checked the voltage at the obd socket pins?
Or try a test light on the obd socket. A bad ground might be enough to show good voltage on a meter but not actually be able to provide enough power to trigger the reader.

 

[m_c]

As @hotponyshoes says, it could be a poor connection. Doesn't opcom take it's main power from the USB? Whereas the rest will take their power from the car.

 

[Kayos]

autel, foxwell and a generic one. As I say opcom works fine, it's just I'd rather use the standalone kit and it doesn't make sense that standalone stuff won't power up off it?!

Opcom was all I've been able to make work on a lot of Astras, even Tech2 struggled on a few after G's

 

[visor_down]

The autel should definitely power on as soon as its connected to any car so i reckon the car end must be the issue.
Have you checked the voltage at the obd socket pins?
Or try a test light on the obd socket. A bad ground might be enough to show good voltage on a meter but not actually be able to provide enough power to trigger the reader.

Yeah so should foxwell
Yeah voltage checked at the pins. I've tested ground with battery disconnected with DVOM no resistance to note.

As @hotponyshoes says, it could be a poor connection. Doesn't opcom take it's main power from the USB? Whereas the rest will take their power from the car.

Yes it does but doesn't explain why the others won't power up with power at the socket and grounds, that should be all they need, regardless of whether they then go on to have comms problems

Opcom was all I've been able to make work on a lot of Astras, even Tech2 struggled on a few after G's

Ah ok cheers 'good' to know, bit of pain but least I won't go chasing my tail, makes no sense to me as to why they wouldn't power up, they're not even checking can/protocol at that point.

 

[jsf55]

Does the car start and run ?

 

[visor_down]

Does the car start and run ?

Yep

 

[Kayos]

Vauxhall messed up the half canbus implementation on a lot of Astras, Opcom has a work around in the software

 

[m_c]

Yes it does but doesn't explain why the others won't power up with power at the socket and grounds, that should be all they need, regardless of whether they then go on to have comms problems

It does.
As the opcom only needs the earth for communication purposes, it's probably only passing maybe 20-30mA through the earth.
The other interfaces are trying to draw more power, so a poor earth would allow communication, but not a device to power up.
A simple test, is to try putting a decent load through the earth and power connections. I have a spare bulb holder I can put a 5/10/21W bulb in to test for these kinds of faults. A standard test lamp or multimeter can show things as fine, when they're not.

Vauxhall messed up the half canbus implementation on a lot of Astras, Opcom has a work around in the software

Vauxhall didn't mess up. They changed the electrical architecture around 2005, from a partial CANbus system to fuller CANbus system to unify things across models.
The easy way to tell what system was used is the radio. IIRC the old system had radios with 4 number models, whereas the new system had radios with 2 number models. They also stopped fitting grubscrews to the radios, as the radios got coded to the vehicle instead of having a pin code.

 

[Kayos]

It does.
As the opcom only needs the earth for communication purposes, it's probably only passing maybe 20-30mA through the earth.
The other interfaces are trying to draw more power, so a poor earth would allow communication, but not a device to power up.
A simple test, is to try putting a decent load through the earth and power connections. I have a spare bulb holder I can put a 5/10/21W bulb in to test for these kinds of faults. A standard test lamp or multimeter can show things as fine, when they're not.


Vauxhall didn't mess up. They changed the electrical architecture around 2005, from a partial CANbus system to fuller CANbus system to unify things across models.
The easy way to tell what system was used is the radio. IIRC the old system had radios with 4 number models, whereas the new system had radios with 2 number models. They also stopped fitting grubscrews to the radios, as the radios got coded to the vehicle instead of having a pin code.

The changeover cars, particularly astras have issues, they cocked something up as I had a genuine Tech2 and it needed a firmware update to work on them, always added new cars with a download before that

 

[m_c]

The changeover cars, particularly astras have issues, they cocked something up as I had a genuine Tech2 and it needed a firmware update to work on them, always added new cars with a download before that

You needed the CANdi module to use Tech2 on the full CANbus cars.