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SPN 3216 FMI 13

Aftertreatment 1 Intake NOx — Out of calibration.
The component or the controller's calibration for it is not within the expected range.

What the SPN covers: NOx sensor reading in the exhaust before the SCR catalyst (engine-out NOx). More on SPN 3216.

What FMI 13 usually points to: A replaced part that needs a calibration or learn procedure, wrong software, or a worn component. More on FMI 13.

Severity

MEDIUM — fix soon

Can lead to SCR efficiency codes and inducement derates if not repaired.

Likely causes

  1. Failed NOx sensor (common)
  2. Sensor not reaching operating temperature
  3. Exhaust leak near the sensor
  4. Network or power fault to the sensor module

Checks & fixes (easiest first)

  1. Check for exhaust leaks upstream of the sensor
  2. Check sensor power/ground and CAN wiring
  3. Compare inlet and outlet NOx readings
  4. Replace sensor per OEM test results

FAQ

What does SPN 3216 FMI 13 mean?

Aftertreatment 1 Intake NOx — out of calibration. The component or the controller's calibration for it is not within the expected range.

Is SPN 3216 FMI 13 serious?

Can lead to SCR efficiency codes and inducement derates if not repaired.

What should I check first for SPN 3216 FMI 13?

Check for exhaust leaks upstream of the sensor; Check sensor power/ground and CAN wiring; Compare inlet and outlet NOx readings.