Hi George
So today I disconnected the emc plug and tested each wire with a new meter that shows 00.0 when probs shorted and here's the values i have.


Wire A Pink wire 21.1 ohms

Wire B White wire 00.0 ohms

Wire C Black White Stripe found values on 3 spots on the ecm connector.Ends of ecm connector 00.0 ohms then there's one pin towards the middle of the ecm connector 0.46 ohms and at the other end of the connector ohms 00.0

Wire D White black stripe ...can't find it on the ecm connectors anywhere. I tried to find it using resistant test and absolutely nothing.



Wire C Black White Stripe The pin that reads 04.6 is in the middle of the green connector and im also getting a reading on the ends on the right and left end ...the very last pin on each side. Far right where the prob is and far left where the prob isn't.

 

When you get a reading of 21.1 ohms on the pink wire, where are your meter leads connected? Is either end of the wire connected to anything?

George

 

One lead at the icm connector with the connector unplugged from the icm and the coil and the other at the ecm with the connector unplugged from the ecm.It shows it going to the ignition switch via fuse box in this schematic.

 

That pink wire at the ICM goes to fused power such as ECM1, depending on the year. Your reading through the ICM and one of the ECM power wires through at least one common fuse.

George

 

My truck is 2005.It should show the same voltage as the battery on the pink which I'm sure it does. I can double check that tomorrow. I'm sure it does or the truck wouldn't start right ? I'll also check both sides of the fuse.

 

With everything hooked back up and with key on check the ICM net voltage by back probing pink and blk/wht at the ICM connector and read DC volts. Should within a few tenths of battery voltage at the battery terminals.

George

 

So I tested them and here's what I found.

Battery + / - 12.08v

Pink / Black White @ icm 11.94v

I also tested Black White @ the icm and Pink on the coil 11.98v

So everything looks good there. Then I thought while I'm at it I'll test white /black wire from the coil to the icm so I back probe it and I have 38.4 ohms which I believe is a problem. This wire was spliced into for my car starter and the place that installed it for me butchered it and I had repaired it with a small piece of wire that I had at the time that's a little thicker gauge soldered it and heat shrunk it a couple years ago. I think this little piece of wire might be acting like a resistor ? So I have enough wire in the harness that I found when I unwrapped it that I can take this thicker piece of wire out now and see if it solves my problem. What's your thoughts on this ? It's the little piece in the picture.

 

If you unplug that wht/blk wire at both ends and get 38 ohms then yes that's a problem, its should be a few tenths of an ohm. A thicker wire is in its self not a problem, it actually has lower resistance. Corrosion, bad soldering joints, etc can cause this, not a thicker wire itself.

George

 

Ok ill unplug it and retest it. I'm a professional at soldering. I've done tons of electronic projects in the past so I know that's not an issue. 😄

 

I thought id look at trouble codes and did think I'd see this many of them. All 3 of my O2 sensors have been replaced with new AC Delco sensors.