FITMENT
Compatible with GM diesel vehicles equipped with SCR (Selective Catalytic Reduction) AdBlue emission systems requiring NOx monitoring.
Common applications include:

• Chevrolet Express 2500 / 3500
• Chevrolet Silverado HD (diesel SCR variants)
• GMC Savana 2500 / 3500
• GMC Sierra HD diesel models (SCR equipped versions)
  Using reference numbers:
• 12671388
• 12669595
• 5WK9 6645H (Continental/VDO sensor family cross-reference)

Designed for exhaust aftertreatment systems to ensure emissions compliance and proper AdBlue dosing control.

FAQ
Q1: What is the function of this NOx sensor?
A1: It measures nitrogen oxide (NOx) levels in the exhaust system and sends data to the ECU to control AdBlue/DEF injection and reduce emissions.

Q2: Where is it installed?
A2: It is installed in the SCR exhaust system, typically upstream or downstream of the catalytic converter depending on configuration.

Q3: What are symptoms of failure?
A3: Check engine light, SCR/DEF warning messages, NOx sensor fault codes, reduced engine power, or limp mode activation.

Q4: Are 12671388 and 12669595 interchangeable?
A4: Yes, both are GM OEM reference numbers used for the same SCR NOx sensor depending on production or system revision.