P2221 Fault Code

NOx Sensor Heater Sense Circuit Bank 2

• What does that mean?
• Symptoms
• Causes
• Solutions

The P2221 fault code refers to an issue with the NOx (Nitrogen Oxide) Sensor Heater Sense Circuit Bank 2. This code is triggered when the Engine Control Module (ECM) detects an abnormal reading from the NOx sensor heater circuit, which is responsible for ensuring that the NOx sensor operates effectively at various temperatures. Proper functioning of the NOx sensor is crucial for compliance with emission standards and optimal engine performance.

What are the symptoms of the P2221 code?

Symptoms associated with the P2221 fault code may include:

• Illuminated Check Engine Light
• Increased emissions due to improper NOx sensor readings
• Decreased fuel efficiency
• Rough engine idle or hesitation during acceleration
• Potential failures during emissions testing

What causes the P2221 code?

Common causes of the P2221 code include:

• Faulty NOx sensor heater
• Damaged wiring or connectors in the sensor circuit
• Short circuit or open circuit in the heater circuit
• Malfunctioning Engine Control Module (ECM)
• Corroded terminals or poor connections

How to fix P2221?

To resolve the P2221 fault code, consider the following steps:

• Inspect the NOx sensor heater and wiring for any visible damage or corrosion.
• Test the voltage and resistance of the NOx sensor heater circuit to ensure it is functioning as intended.
• Replace the NOx sensor if it is found to be defective.
• Repair any damaged wiring or connectors noticed during inspection.
• Clear the fault codes and perform a test drive to see if the code reappears.