1v voltage drop on relay switched ground

Hi , I have a vw crafter 2011 tdi intermittent no start. I found a 1v voltage drop at the engine ecu controll relay switched earth. It was measured at both the relay and the ecu plug.
An ecu repairer told me its not enough to cause an issue however i can see its not switchin the relay all the time.
is this drop enough to cause the issue and warrant ecu repair? 
many thanks. 
 

Can you post a diagram to help visualize where and how you are testing?

hi yes here are the pics.
I measured the same voltage at both the relay its self and the ecu pin a69.
I measured voltage drop across the ground to battery negative directly.
the ecu powers and grounds checked out ok.

many thanks.

 

Hi Chad,
thanks for your reply, i have posted the diagram many thanks.

Butch wrote:

i can see its not switchin the relay all the time.
is this drop enough to cause the issue

 

1 volt on a control ground is not good, in my opinion. I would try to activate the relay, from the ECU connector, with an external ground connected directly to the negative battery post to see if the relay functions more consistently.

Hopefully, some others will chime in.

Hi, Chad
yes i did switch it externally and it did switch on.
i also run the relay in a tester and it switched every time (over 30 times).
Thanks so much for your reply its great to have some one agree with me after being told by the ecu expert that its ok.