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Basic multimeter is good. Wire/ connector disconnected at both ends , meter on lowest ohms scale and measure resistance between both ends of the wire. Then meter on 20vdc, first probes from wire to battery positive then wire to battery negative.
All of these tests need a completely isolated wire that connects the egr position sensor output to the vcm input. Then you perform the three measurements.
OK so with harness disconnected at both ends from vcm and egr, I'm testing from brown terminal on egr connector to battery?
BTW, which is C2? Mine just says White and Black above the connectors. Unless what I think is the VCM is not the VCM 😂
Edit: I think I found C2 is the lower inside connector. Now I'm fighting with getting the blue safety clip off. Seriously is it easier to just unbolt the vcm to reach that thing?
Last edited by ferret13sj; Mar 3, 2022 at 02:07 PM.
Reason: More info
Your EGR valve has 5 wires - Red, Black, Brown, Gray and White. The wire that we are testing is brown which is the EGR position sensor output to the VCM. Your VCM has 4 connectors. C2 can be confirmed by looking at the wire color pattern and pin 10/brown is conformed by counting 10 slots from each connector row end and then confirming the surrounding wires. IDK how that particular connector comes off.
Wire/ connector disconnected at both ends , meter on lowest ohms scale and measure resistance between both ends of the brown wire to the EGR. Then meter on 20vdc, first probes from brown wire to battery positive then brown wire to battery negative.
OK I'll fight with the connector however I need to. So testing the isolated wire, connected to absolutely nothing, will tell me if it's shorted to ground or hot. I think I understand....
First we are trying to figure out if there is a clean low resistance connection from one end of the wire to the other. Then while your there you want to make sure that the wire is not shorted to battery positive or battery ground. There is one more rare possibility that you are shorted to another signal wire but this is beyond the scope of most home mechanics z
Since its a PITA to get to the VCM connectors, lets check continuity and short to power and ground on the last two wires between the EGR and VCM - Red and White. Both land on the VCM connector C4 which is the only 24 pin. Red on pin 16 and white on pin 20:
