FITMENT:
Compatible with Ram heavy-duty trucks equipped with 6.7L Cummins diesel engines and SCR (AdBlue/DEF) emission systems, including:

• Ram 2500 (2011–2012)
• Ram 3500 (2011–2012)
• Ram 4500 (2011–2012)
• Ram 5500 (2011–2012)

OEM reference number: 68067521AA (also superseded by 68067521AB).

Used in diesel exhaust aftertreatment system for NOx monitoring (SCR system).
Installed in upstream (pre-catalyst / inlet) position before SCR catalyst to measure engine-out NOx for AdBlue dosing control.

FUNCTION:

• Measures nitrogen oxide (NOx) levels before SCR catalyst
• Sends data to ECU for DEF/AdBlue dosing control
• Helps maintain emissions compliance (EPA / Euro equivalent systems)
• Prevents SCR faults and engine derate conditions

INSTALLATION POSITION:

• Upstream (inlet) NOx sensor
• Located between turbo/DPF outlet and SCR catalyst section

FAQ:

Q1: Is this inlet or outlet sensor?
A1: This is the upstream (inlet) NOx sensor for Ram 6.7L Cummins SCR systems.

Q2: What vehicles does it fit?
A2: 2011–2012 Ram 2500, 3500, 4500, and 5500 with 6.7L diesel engines.

Q3: What happens if it fails?
A3: Check engine light, SCR/DEF faults, incorrect NOx readings, reduced engine power, or limp mode.

Q4: Is 68067521AA interchangeable with 68067521AB?
A4: Yes, AB is the updated supersession version of AA.

Q5: Does replacement require programming?
A5: Some trucks require SCR reset or ECM adaptation after installation.