NOx Sensor Circuit Bank 1 Open (Generic)
The P4024 code means the vehicle's onboard diagnostic system has detected: NOx Sensor Circuit Bank 1 Open (Generic). This is a critical severity code.
- Keep driving?
- No -- stop driving
- DIY difficulty
- hard
- Estimated cost
- $300 - $800 (parts and labor)
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Common Symptoms
- Check Engine Light on
- SCR system disabled
- DEF warning light on
- Reduced engine power
- Increased NOx emissions
Probable Causes (Ranked by Likelihood)
- Open circuit in NOx sensor wiring Very High
- Failed NOx sensor High
- Damaged connector at sensor Moderate
- PCM NOx input failure Low
Step-by-Step Diagnostic Procedure
-
Check NOx sensor connector and wiring for open circuit
-
Test sensor power supply and communication
-
Verify CAN bus communication with NOx sensor module
-
Replace NOx sensor if internal failure confirmed
Frequently Asked Questions
What is a NOx sensor?
A NOx sensor measures nitrogen oxide levels in the exhaust. It is critical for the selective catalytic reduction system that uses diesel exhaust fluid to reduce emissions.
Can I drive with P4024?
No, the vehicle will likely enter a countdown to reduced power mode. The SCR system requires NOx data to function properly.
How much does a NOx sensor cost?
NOx sensors are expensive, typically $250-600 for the part alone. With labor, expect $400-800 total.
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