Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the car's computer found a problem with a part that helps reduce pollution. It's like a heater that isn't working right.
The P23BB code indicates that the resistance in the heater circuit of the NOx sensor on Bank 1, Sensor 3, is outside the expected range.
The NOx sensor is equipped with a heater to ensure it reaches the optimal operating temperature quickly. The engine control module (ECM) monitors the resistance of this heater circuit. If the resistance is not within the specified parameters, the ECM triggers the P23BB code.
• Check Engine Light is on
• Reduced fuel efficiency
• Increased emissions
• Possible limp mode activation
• Faulty NOx sensor heater
• Poor electrical connection in the NOx sensor circuit
• Blown fuse related to the NOx sensor heater
• Damaged wiring or connectors
NOx: Nitrogen Oxides, pollutants produced during combustion.
ECM: Engine Control Module, the computer that manages engine functions.
• Use an OBD-II scanner to confirm the code.
• Inspect the NOx sensor and its wiring for damage.
• Check the resistance of the NOx sensor heater circuit.
• Test the power supply and ground to the NOx sensor.
• Replace the faulty NOx sensor.
• Repair or replace damaged wiring or connectors.
• Replace any blown fuses.
• Ensure proper connection and secure mounting of the sensor.
• OBD-II scanner
• Multimeter
• Basic hand tools
$200 - $600
Moderate
• Chevrolet Silverado
• Ford F-250
• Dodge Ram 2500
• Regular maintenance checks
• Inspect wiring and connectors periodically
• Use high-quality fuel to reduce sensor contamination
Sensor Issue
• Do not ignore the Check Engine Light.
• Have your vehicle inspected by a professional if unsure.
• Keep up with regular vehicle maintenance.
Check with your vehicle manufacturer for emissions-related warranty coverage.
This code has become more common with newer vehicles equipped with advanced emissions control systems.
Moderate – Addressing this issue is important to maintain vehicle performance and emissions compliance.
Driving with a faulty emissions control component may result in failing emissions tests and is illegal in some areas.
• Engine at operating temperature
• Vehicle in closed-loop operation
The NOx sensor is typically located in the exhaust system, downstream of the catalytic converter.
Q: What does a NOx sensor do?
A: A NOx sensor measures the levels of nitrogen oxides in the exhaust to help control emissions.
Q: Can I drive with a P23BB code?
A: While you may be able to drive, it's not recommended as it can lead to increased emissions and reduced performance.
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Fitment Required · Vehicle-fitment part
Relevant when catalyst-efficiency or emissions faults persist after proper diagnosis.
Catalyst-efficiency faults sometimes point toward converter problems after proper testing.
Catalytic converters are highly vehicle-specific and should not be purchased by code alone.
View options on AmazonThese parts may be related to this fault category, but a code by itself does not confirm exact fitment or guarantee that replacing a part will solve the problem.