Technical ELM327 wont connect to the ECU?

[Pacora]

Hi all,
I've bought the ELM327 OBDII USB cable and the adapters that are recommend for use with MultiECUscan and FiatECUscan (both free versions) but im still having trouble connecting to the ECU of my Grande.
I've got the COM ports set up correctly and the software can see the cable and confirms that it 'should' work, but everytime i try to connect it comes up with 'ELM327>ECU connection failed, check cables and COM ports'
Any help would be appreciated

 

[Andy Monty]

Is it a modified elm or a standard one?

 

[Pacora]

Just a generic one from fleabay, wasn't expensive

 

[culdaraul]

Hello.
I have the same problem. I bought an ELM327 (original one) last year and it worked several times, but few weeks ago it wouldn't connect anymore, altough I double checked all settings.
I think that maybe a "hard" reset by disconnecting and connecting back the battery would solve the problem. I will try tomorrow.

 

[cmosfxx]

I don't know but maybe that's why?

http://hardware.slashdot.org/story/...from-windows-update-that-bricked-cloned-chips

 

[Pacora]

I read something about it being cheaper cables having a problem with the Grande, but I don't want to go and spend a fortune on one if its just going to continue to not connect!

 

[g8rpi]

Just a generic one from fleabay, wasn't expensive

There is a design issue with many of the Chinese ELM clones. They slavishly followed the "applaication circuit" in the datasheet for the CAN transceiver integrated circuit which shows a a 120 ohm terminating resistor across the CAN bus. Unfortunatly there should only be a resistor across each END of the whole bus (two in total), not one across each transcever IC. The extra IC loads the bus and changes the voltage levels. On some cars it works, some it doesn't. Sometimes it only affects some modules. The fix is to remove this resistor. You can tell if your interface is affected by using a multimeter to measure the resistance between pin 6 and Pin 14. If it is between 100 and 150 ohms the unit has a terminating resistor that should be removed.
Where are you located and what was the ebay number of the interface?

Robert G8RPI.

 

[Pacora]

There is a design issue with many of the Chinese ELM clones. They slavishly followed the "applaication circuit" in the datasheet for the CAN transceiver integrated circuit which shows a a 120 ohm terminating resistor across the CAN bus. Unfortunatly there should only be a resistor across each END of the whole bus (two in total), not one across each transcever IC. The extra IC loads the bus and changes the voltage levels. On some cars it works, some it doesn't. Sometimes it only affects some modules. The fix is to remove this resistor. You can tell if your interface is affected by using a multimeter to measure the resistance between pin 6 and Pin 14. If it is between 100 and 150 ohms the unit has a terminating resistor that should be removed.
Where are you located and what was the ebay number of the interface?

Robert G8RPI.

Is that pin 6 and 14 starting from the smaller side or the larger side of the plug?
I'm located Wisbech way and the link for the EBay item is: http://pages.ebay.com/link/?nav=item.view&id=181648381328&alt=web
Many thanks!

 

[g8rpi]

Hi, thats pins No 6 and 14 one on the top row one on bottom. See:



I'm near Cambridge (Bar Hill) so if you ever get over this way I'm happy to remove the resistor in your interface and / or try my interface on your car.

Robert.