NOx Sensor Circuit Bank 2 Range/Performance (Generic)
The P4029 code means the vehicle's onboard diagnostic system has detected: NOx Sensor Circuit Bank 2 Range/Performance (Generic). This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- hard
- Estimated cost
- $300 - $800 (parts and labor)
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Common Symptoms
- Check Engine Light on
- Bank 2 NOx readings out of expected range
- Uneven SCR performance between banks
- DEF consumption mismatch
Probable Causes (Ranked by Likelihood)
- Bank 2 NOx sensor contamination Very High
- Exhaust leak near bank 2 sensor High
- Bank 2 SCR catalyst degradation Moderate
- DEF distribution imbalance Low
Step-by-Step Diagnostic Procedure
-
Compare bank 1 and bank 2 NOx readings at various loads
-
Check for exhaust leaks near bank 2 NOx sensor
-
Inspect bank 2 DEF injection system
-
Test bank 2 NOx sensor with manufacturer tool
Frequently Asked Questions
Why would one bank perform differently?
On V-configuration engines, each bank has separate exhaust and SCR systems. One bank may have a clogged DEF injector or degraded catalyst while the other is fine.
Can I drive with P4029?
You can drive short distances but a derate countdown may be active. Address the issue promptly to avoid speed limitation.
How do I tell if it is the sensor or the SCR?
Compare the NOx reduction percentage across both banks. If bank 2 shows lower reduction, the SCR catalyst or DEF injector on that side is likely the issue.
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