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 thinks there's a problem with how air is flowing into the engine. It's like when you try to breathe through a straw and it's not working right.
The P2391 code indicates an issue with the control performance of the diesel engine's intake air flow system, specifically related to the 'B' circuit or component.
The P2391 code is triggered when the Engine Control Module (ECM) detects a performance issue with the intake air flow control system for diesel engines. This could involve sensors, actuators, or the intake manifold itself. The 'B' designation refers to a specific part of the system, which may vary by manufacturer.
• Check Engine Light is on
• Reduced engine performance
• Poor fuel economy
• Faulty intake air flow sensor
• Blocked or restricted air intake
• Malfunctioning intake air control valve
ECM: Engine Control Module, the computer that controls engine functions.
Intake Manifold: Part of the engine that distributes air to the cylinders.
• Use an OBD-II scanner to confirm the code.
• Inspect the air intake system for blockages.
• Test the intake air flow sensor and control valve.
• Clean or replace the air intake filter.
• Repair or replace the intake air flow sensor.
• Repair or replace the intake air control valve.
• OBD-II scanner
• Multimeter
• Screwdriver set
$150 - $500
Moderate
• Ford F-250
• Chevrolet Silverado 2500
• Ram 2500
• Regularly replace air filters.
• Perform routine maintenance checks.
• Ensure no blockages in the air intake system.
Engine Performance
• Avoid driving at high speeds until the issue is resolved.
• Consult with a professional mechanic for a thorough diagnosis.
Check with the vehicle manufacturer for warranty coverage on engine components.
This code has been associated with diesel engines and typically arises from maintenance neglect or component wear.
Moderate – Addressing this code promptly can prevent further engine performance issues.
Driving with an unresolved engine issue can lead to safety hazards. Ensure repairs are performed by a qualified technician.
• Engine at operating temperature
• Vehicle in idle or low-speed conditions
The intake air flow sensor and control valve are typically located near the air intake manifold or air filter housing.
Q: Can I drive with a P2391 code?
A: It's not recommended to drive for extended periods with this code, as it can lead to reduced engine performance and efficiency.
Q: What happens if I ignore the P2391 code?
A: Ignoring this code can lead to poor engine performance and potentially more severe engine damage over time.
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Fitment Required · Vehicle-fitment part
Relevant for airflow, fuel-trim, and intake-metering faults after confirming the sensor is actually at fault.
Airflow and fuel-trim codes can involve the mass air flow sensor after proper diagnosis.
Verify the sensor design and fitment for your exact vehicle.
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.