These NOx sensors are very expensive so before buying one I want to make sure I have done due diligence and test as much as possible. The harness and connectors look good on visual inspection. Power Pin 4 to battery ground is good
Tested the powers and grounds at the connector which were fine, Power between pins 3 and 4 good (same as pin 4 to battery) Voltage on J1939 pin 1 (+) to ground 2.5v. Voltage on J1939 pin 2 (-) to ground 2.4v
The comm capture I have from J1939 pins 1 and 2 with the ignition on which looks clean. At this point I’m leaning toward a bad NOx sensor and module but I’m going to do a few more tests before placing the order with Dodge.Then used an automotive scope to check the CAN bus signal with the module disconnected and the CAN bus signal was fine. Rechecked with the module connected and the CAN signal was distorted. I bench tested the NOx sensor and found no normal can signal coming from the module. Recommend replace the sensor and module.
A new Module was installed and communication was restored between the PCM and NOx module.
Clean signal when checked at the harness side connector (front probed)
Clean signal when disconnected from NOx module (back probed)
Distorted signal when connected to NOx module (back probed)
NOx module on bench
New module installed and the graphs look good on the test drive.
