NOx Sensor Heater Circuit Low (Bank 1)
What does P2206 mean?
The P2206 code means the vehicle's onboard diagnostic system has detected: NOx Sensor Heater Circuit Low (Bank 1). This is a moderate severity code.
Common Symptoms
- Check Engine Light on
- Prolonged sensor warm-up time
- Cold start emissions issues
- Possible reduced power mode
- Failed emissions test
Probable Causes (Ranked by Likelihood)
- Open circuit in the NOx sensor heater wiring Very High
- Failed heater element inside the NOx sensor High
- Corroded heater circuit connector Moderate
- Poor ground connection for the heater Moderate
- ECM heater control driver failure Low
Step-by-Step Diagnostic Procedure
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Measure voltage at the NOx sensor heater connector with key on -- should have battery voltage
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Check heater ground circuit for continuity back to the ECM
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Measure heater element resistance -- an open reading indicates a failed heater
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Inspect connectors for corrosion or backed-out pins
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Replace the NOx sensor if the internal heater has failed
Frequently Asked Questions
What does heater circuit low mean?
It means the current flow through the NOx sensor heater circuit is below the expected minimum, typically caused by an open circuit, bad connection, or failed heater element.
Can I test the NOx sensor heater with a multimeter?
Yes, you can measure the heater element resistance at the sensor connector. A typical reading is 2 to 10 ohms depending on the manufacturer. An open (infinite) reading means the heater has failed.
Is the heater element replaceable separately?
No, the heater is built into the NOx sensor assembly. If the heater fails, the entire sensor must be replaced.