NOx Sensor Heater Circuit Intermittent (Bank 2)
The P2218 code means the vehicle's onboard diagnostic system has detected: NOx Sensor Heater Circuit Intermittent (Bank 2). This is a low severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- hard
- Estimated cost
- $50 - $800 (parts and labor)
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Common Symptoms
- Intermittent Check Engine Light
- Occasional slow Bank 2 sensor warm-up
- Sporadic emissions warnings
- Inconsistent cold-start performance
- Occasional SCR system fault
Probable Causes (Ranked by Likelihood)
- Loose connection at the Bank 2 NOx sensor heater connector Very High
- Partially broken wire in the Bank 2 heater circuit High
- Corroded connector pins causing intermittent contact Moderate
- Bank 2 heater element with intermittent internal failure Moderate
- Vibration-related wiring issues on Bank 2 Low
Step-by-Step Diagnostic Procedure
-
Wiggle test the Bank 2 connector while monitoring heater current
-
Inspect the Bank 2 heater circuit wiring for chafing or partial breaks
-
Clean and apply dielectric grease to connector pins
-
Monitor heater performance over multiple cold starts
-
Replace the sensor if wiring checks pass but fault persists
Frequently Asked Questions
Why does the Bank 2 heater code come and go?
Intermittent heater codes are typically caused by a loose connector, partially broken wire, or corroded pin that only fails under certain conditions like vibration or temperature changes.
Should I fix an intermittent heater code?
Yes, even though it is intermittent, the issue will likely worsen. Addressing it early usually means a cheaper repair -- often just cleaning connectors or repairing wiring.
Can I prevent NOx sensor heater issues?
Regular inspection of the wiring harness and connectors, especially after winter when road salt and moisture exposure is high, can help prevent intermittent connection issues.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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