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cumminsdr
cumminsdr, Mechanic
Category: Medium and Heavy Trucks
Satisfied Customers: 3544
Experience:  All types of Cummins applications
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Im looking wiring diagram nox sensor on a freightliner

Customer Question

Im looking for a wiring diagram for the nox sensor on a freightliner medium duty with a cummins engine. i have code 3226 9
JA: Thanks. Can you give me any more details about your issue?
Customer: have cel, also kicks into reduced power. i am having difficulty getting wiring diagrams with pin locations at ecm and nox sensor, and voltage values
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Submitted: 10 months ago.
Category: Medium and Heavy Trucks
Expert:  cumminsdr replied 10 months ago.

What is your engine serial number?

Customer: replied 10 months ago.
73207146
Customer: replied 10 months ago.
Whats the eta of some diagrams? just getting finished for the day and off to job #2 tonight. hoping for answers before then
Expert:  cumminsdr replied 10 months ago.

Sorry just got your response. Thanks for letting Just Answer assist

Fault Code: 2771
PID:
SPN: 3226
FMI: 9

Aftertreatment Outlet NOx Sensor - Abnormal Update Rate. No communications or an invalid data transfer rate detected on the J1939 data link between the engine control module and the aftertreatment outlet NOx sensor.

Aftertreatment outlet NOx sensor operation will be disabled.

The Aftertreatment Outlet NOx Sensor location is usually located in the exhaust system at the outlet of the aftertreatment SCR catalyst.

Possible causes of this fault code include:

  • The Aftertreatment Outlet NOx Sensor is not receiving power from the battery supply circuit in the OEM harness. This can be caused by an open circuit in the power supply wire, blown NOx sensor fuse, or low voltage supplied by the battery. Fuses is located in the distribution(black box ) on drivers side under the hood
  • Open return circuit on the aftertreatment outlet NOx sensor battery return.
  • Open or short circuit on the J1939 data link circuit between the engine control module and aftertreatment outlet NOx sensor.
  • Intermittent communications between the aftertreatment outlet NOx sensor and the primary engine control module on the J1939 data link.
  • A damaged engine control module.
  • For intermittent power supply and datalink communication issues with Aftertreatment Components, it is highly recommended that the OEM Power Distribution Center fuses and relays be thoroughly checked for loose, missing or intermittent connections.

Please don't forget to rate my service.

Customer: replied 10 months ago.
I was asking for the wiring diagrams, because I need to know which pin at ecm is my signal from nox ecu. And values at the nox plug in as well
Expert:  cumminsdr replied 10 months ago.

Its on the diagram I sent. Pin 08 or 18. and transmits data to the ecm via the j1939 data link. It ia a smart service and only needs power to work The computer chip communicates with the ecm

Measure the voltage between the aftertreatment outlet NOx sensor battery voltage supply circuit and the aftertreatment outlet NOx sensor return circuit at the NOx sensor wiring harness connector. should read battery voltage.

Thats the only valve you are going to get for troubleshooting the nox sensor.

I can send you the proper troubleshooting tree if needed.

Expert:  cumminsdr replied 10 months ago.

You can also check the j1939 circuit

  • Turn keyswitch OFF.
  • Disconnect the aftertreatment outlet NOx sensor from the OEM harness.
  • Disconnect the engine harness from the ECM connector.
  • Measure the resistance between the SAE J1939 data link (+) wire at the aftertreatment outlet NOx sensor OEM harness connector and the SAE J1939 data link (+) wire at the ECM engine harness connector.
  • Measure the resistance between the SAE J1939 data link (−) wire at the aftertreatment outlet NOx sensor OEM harness connector and the SAE J1939 data link (−) wire at the ECM engine harness connector.

should be Less than 10 ohms, if not An open circuit has been detected in the J1939 data link. Troubleshoot the engine harness, OEM harness, and all interconnects.

  • Turn keyswitch OFF.
  • Disconnect the aftertreatment outlet NOx sensor from the OEM harness

Measure the terminating resistance of the SAE J1939 data link.

  • Measure the resistance between the SAE J1939 data link (+) wire and the J1939 data link (-) wire at the aftertreatment outlet NOx sensor OEM harness connector.

It should read 50 to 70 ohms

There are some other checks I have not added untill you see what is going on?

Expert:  cumminsdr replied 10 months ago.

Hi just following up. please don't forget to rate my service

Expert:  cumminsdr replied 10 months ago.

Please don't for get to rate my service

Expert:  cumminsdr replied 9 months ago.

Hi just following up. Please don't forget to rate my service..

Expert:  cumminsdr replied 9 months ago.

Please don't forget to rate my service.

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