SPN 3216 — Aftertreatment 1 Intake NOx
System: Aftertreatment / SCR
NOx sensor reading in the exhaust before the SCR catalyst (engine-out NOx).
Can I keep running it?
MEDIUM — fix soon
Can lead to SCR efficiency codes and inducement derates if not repaired.
Likely causes
- Failed NOx sensor (common)
- Sensor not reaching operating temperature
- Exhaust leak near the sensor
- Network or power fault to the sensor module
Checks & fixes (easiest first)
- Check for exhaust leaks upstream of the sensor
- Check sensor power/ground and CAN wiring
- Compare inlet and outlet NOx readings
- Replace sensor per OEM test results
Common FMIs with SPN 3216
- SPN 3216 FMI 2Data erratic, intermittent, or incorrect
- SPN 3216 FMI 4Voltage below normal or shorted low
- SPN 3216 FMI 10Abnormal rate of change
- SPN 3216 FMI 12Bad intelligent device or component
- SPN 3216 FMI 13Out of calibration
- SPN 3216 FMI 20Data drifted high
Related codes
FAQ
What does SPN 3216 mean?
SPN 3216 is Aftertreatment 1 Intake NOx. NOx sensor reading in the exhaust before the SCR catalyst (engine-out NOx).
Can I keep running with SPN 3216?
Can lead to SCR efficiency codes and inducement derates if not repaired.
What causes SPN 3216?
Failed NOx sensor (common); Sensor not reaching operating temperature; Exhaust leak near the sensor; Network or power fault to the sensor module.