Cm2250 nox sensor power wire failing load test

[Rawze]

(10-18-2021 )Gcc Wrote:  Well i guess ill have to try an get a different multimeter as i get 60 ohms at plug and sensor but after key is turned off in getting 0.00 ohms at the whether pack not my first time using an ohm meter either

The terminating resistors (they are 120-ohms each) are 'NOT' hard-wired into the wiring harness themselves.

There are TWO different networks...
- For can#2 (The engine has its own separate J1939 nertwork), One of these terminating resistors is located directly inside the VGT turbo controller. The other is usually down at the DFP/SCR (emissions) system harnesses, far down at the other end.

Can#1 (the truck J1939 network) is separate form this, and communicates with the truck side of things. It is a separate network, and is the one that has the deutsch (big round plug) connector under the dash. It also has terminating resistors.. depends on the truck where they are at. Maybe one of them is in the truck OEM harness, up by the ecm, and the other one is usually down by any Automatic tranny harness, or bunk heating/a/c controller that the truck may have.

On the engine side harness, for can#2 ... The green and yellow twisted pair located at the 3-pin 'weather pack' connector, should read 60-ohms with the truck turned off.

Same thing with the can#1 harness green/yellow twisted pair at the deutsch connector under the dash.

There are 2 different, seperate networks for the engine/truck, and they BOTH have to be checked. They should BOTH read read 60-ohms with everything shut off after a few minutes.

For can#2, This should be true even if the ECM itself was completely unplugged from the engine harness!.