Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
Your car has a system that helps reduce pollution by cooling down some gases before they go back into the engine. This code means that the part that controls this cooling system on one side of your engine is not working right.
The EGR (Exhaust Gas Recirculation) system is designed to reduce emissions by recirculating a portion of the exhaust gases back into the engine cylinders. The EGR cooler bypass control circuit is responsible for controlling the flow of exhaust gases through the EGR cooler. A 'high' circuit condition indicates that there is a higher than expected voltage in the circuit, which could be due to a malfunctioning component or wiring issue.
The P2491 code is triggered when the Engine Control Module (ECM) detects a high voltage condition in the EGR cooler bypass control circuit for bank 2. This could be due to a fault in the bypass valve, wiring issues, or a problem with the ECM itself. Bank 2 refers to the side of the engine that does not contain cylinder 1, typically applicable in V-type engines.
• Check Engine Light is on
• Reduced engine performance
• Increased emissions
• Faulty EGR cooler bypass valve
• Damaged or corroded wiring or connectors
• Faulty ECM
EGR: Exhaust Gas Recirculation
ECM: Engine Control Module
• Use an OBD-II scanner to confirm the code
• Inspect the EGR cooler bypass valve and its wiring for damage
• Test the voltage and continuity of the EGR cooler bypass control circuit
• Replace the EGR cooler bypass valve if faulty
• Repair or replace damaged wiring or connectors
• Reprogram or replace the ECM if necessary
• OBD-II scanner
• Multimeter
• Basic hand tools
$150 - $500
Moderate
• Ford F-150
• Chevrolet Silverado
• Dodge Ram
• Regular maintenance of the EGR system
• Inspect and clean EGR components periodically
• Use quality fuel to reduce emissions
Sensor Issue
• Do not ignore the Check Engine Light
• Seek professional diagnostic help if unsure
• Avoid hard driving until the issue is resolved
Check with your vehicle manufacturer as EGR components may be covered under emissions warranty.
EGR-related issues have been common in vehicles as emissions standards have become stricter, leading to more complex systems.
Moderate – While the vehicle may still be drivable, it is important to address the issue to prevent increased emissions and potential engine damage.
Driving with a malfunctioning EGR system may lead to increased emissions, which could be against environmental regulations.
• Engine at operating temperature
• Vehicle stationary or at idle
The EGR cooler bypass valve is typically located near the EGR cooler on the engine's exhaust side, on bank 2.
Q: Can I drive with a P2491 code?
A: While you can drive short distances, it's best to fix the issue soon to avoid increased emissions and potential engine damage.
Q: What does 'Bank 2' mean?
A: Bank 2 refers to the side of the engine opposite to where cylinder 1 is located, usually in V-type engines.
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