Technical Car/Motor Issues > Ford Focus III - 20 2.5 No communitcation to ECU from OBD2 port Specialists
Thread Author: colinod Replies: 3
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New Wed 5 Nov 14 12:44 
 Ford Focus III - 20 2.5 No communitcation to ECU from OBD2 port - colinod
I had a problem with my OBD2 port and think someone has swapped around the CAN High and CAN low cables in the port.

The car runs fine with no errors but communication with ECU through OBD port is very erratic, most of the time i have no connection with my code reader so took it to auto electricians and they managed to connect computer after trying for ages

Would these cables being swapped round cause this?

Thanks
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New Wed 5 Nov 14 17:36 
 Ford Focus III - 20 2.5 No communitcation to ECU from OBD2 port - carmalade
Ford use high speed and medium speed can at the obd socket .What colour wires and pin numbers do you have at the obd socket?
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New Thu 6 Nov 14 09:02 
 Ford Focus III - 20 2.5 No communitcation to ECU from OBD2 port - colinod
I may have had the pins for high and low put back in the wrong place and have read somewhere that ford have been known to reveres the colour of these cables on some cars

Is this possible

Currently have pin 6 grey with red stripe and pin 14 is blue

I had someone make up a OBD lead that swaps the pins around so then you have to swap the pins around in OBD port to match so port is useless unless you use the lead as i have key-less starts and lots of my type of car are being taken using port to clone keys.

We never checked the layout of pins before moving and am now thinking that the two CAN pins may have been reversed as i have read but i cannot find where i found that information now.

Just thinking that if i swap the pins around in the OBD port would that cause a problem to test?

Is there a difference in voltage on the two wires that i could check with multi meter?

thanks

Last edited by: colinod on Thu 6 Nov 14 at 09:03
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New Thu 6 Nov 14 18:40 
 Ford Focus III - 20 2.5 No communitcation to ECU from OBD2 port - carmalade
I cant think why Ford would want to reverse to pins on the obd socket,they are all produced the same way.The connector wires to the obd socket and can are as follows;
Hi speed can are pins 6 (gray/red)and 14 (blue/red)
Medium speed can are pins 3 (gray) and pin 11 (blue)
Best way to check the can system is with an oscilloscope or can analyser.This will do the job/www.warwickcontrol.com/
Last edited by: carmalade on Thu 6 Nov 14 at 18:41
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