The P2221: NOx Sensor Heater Sense Circuit Bank 2 refers to a malfunction in the NOx sensor heater sense circuit on bank 2. This can be caused by a faulty sensor, wiring issues, or connector problems, resulting in the sensor heater not working correctly.
P2221 – Quick Overview
Code | Information |
---|---|
Meaning | P2221: NOx Sensor Heater Sense Circuit Bank 2 |
Is it serious? | Yes, this can lead to inaccurate NOx readings, which can affect emissions control and engine performance. |
Possible causes | – Faulty NOx sensor heater sense circuit in bank 2 – Wiring issues or connector problems – NOx sensor malfunction |
How to diagnose? | – Inspect the NOx sensor heater sense circuit in bank 2 – Test the NOx sensor heater sense for proper operation – Check wiring and connectors for faults |
P2221 Meaning
The P2221: NOx Sensor Heater Sense Circuit Bank 2 code indicates that the engine control module (ECM) has detected a fault in the heater sense circuit for the NOx sensor in bank 2 (the side of the engine that does not contain cylinder 1). The sense circuit monitors the heater’s operation, ensuring it heats the NOx sensor to the correct temperature. A failure in this circuit can lead to incorrect NOx readings, impacting emissions control and engine efficiency.
Step-by-step diagnostic guide
Action | Description | Tools Needed |
---|---|---|
Check for Other Codes | Use an OBD-II scanner to check for any additional related codes that might provide further information about the NOx sensor heater issue. | OBD-II Scanner |
Inspect the NOx Sensor Heater Sense Circuit | Visually inspect the NOx sensor heater sense circuit for signs of damage, corrosion, or loose connections in the wiring and connectors in bank 2. | Flashlight, Safety Gloves |
Test the NOx Sensor Heater Sense | Use a multimeter or diagnostic tool to test the NOx sensor heater sense for proper operation. Compare readings to manufacturer specifications to ensure correct functionality. | Multimeter, Diagnostic Tool |
Inspect Wiring and Connectors | Inspect the wiring and connectors related to the NOx sensor heater sense circuit in bank 2 for damage or faults that could be causing the malfunction. | Flashlight, Multimeter |
Test Circuit Continuity | Use a multimeter to check for continuity in the heater sense circuit to ensure proper current flow between the sensor and ECM. Faults can occur due to high resistance or breaks in the wiring. | Multimeter, Wiring Diagram |
Repair or Replace Faulty Components | If any wiring, connectors, or sensor issues are found, repair or replace them as necessary to restore proper function. | Replacement Parts, Tools |
Clear the Code and Test Drive | After repairs, clear the P2221 code using an OBD-II scanner and take the vehicle for a test drive to ensure the issue is resolved. | OBD-II Scanner |
Recheck for Codes | After the test drive, re-scan the vehicle to confirm that the P2221 code does not return. | OBD-II Scanner |

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