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 has detected that the mixture of air and fuel in cylinder 11 of the engine is not right, and it can't adjust it properly.
The engine control module (ECM) monitors the air-fuel ratio in each cylinder. If it detects that cylinder 11's air-fuel mixture is outside the normal range and cannot be corrected, it triggers this code.
The P231E code indicates that the ECM has detected an air-fuel ratio imbalance in cylinder 11. The ECM attempts to adjust the fuel trim to correct the imbalance, but if the adjustment reaches its limit without achieving the desired balance, the code is set.
• Check Engine Light is on
• Poor fuel economy
• Rough idle
• Engine misfire
• Reduced engine performance
• Faulty fuel injector in cylinder 11
• Vacuum leak affecting cylinder 11
• Faulty oxygen sensor
• Ignition system issues
• Exhaust leak near cylinder 11
ECM: Engine Control Module
Fuel Trim: Adjustments made by the ECM to the air-fuel mixture
• Use an OBD-II scanner to confirm the code.
• Inspect the fuel injector for cylinder 11.
• Check for vacuum leaks around cylinder 11.
• Test the oxygen sensor for proper operation.
• Inspect the ignition system components.
• Replace or clean the fuel injector for cylinder 11.
• Repair any vacuum leaks found.
• Replace the faulty oxygen sensor.
• Repair or replace ignition system components.
• Fix any exhaust leaks.
• OBD-II scanner
• Fuel pressure gauge
• Multimeter
• Vacuum gauge
• Basic hand tools
$150 - $600
Moderate
• Vehicle 1
• Vehicle 2
• Vehicle 3
• Regular maintenance of the fuel system
• Use high-quality fuel
• Regularly inspect and replace air filters
Engine Performance
• Do not ignore the Check Engine Light.
• Seek professional diagnosis if unsure.
• Regular vehicle maintenance can prevent this issue.
Check with your vehicle manufacturer for warranty coverage on emissions-related components.
This code has been associated with fuel system issues and is more common in vehicles with high mileage.
Moderate – It should be addressed soon to prevent further engine damage.
Driving with an imbalanced air-fuel ratio can lead to increased emissions and may not comply with local emissions regulations.
• Engine at operating temperature
• Vehicle running at idle
Cylinder 11 is part of the engine block, typically located on the driver's side in a V-engine layout.
Q: Can I drive with a P231E code?
A: It's not recommended to drive for extended periods with this code as it can lead to more serious engine problems.
Q: Will a P231E code affect my fuel economy?
A: Yes, an air-fuel ratio imbalance can lead to poor fuel economy.
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Fitment Required · Vehicle-fitment part
Relevant when the code or supporting diagnostics point toward upstream or downstream oxygen-sensor faults.
This code family often involves upstream or downstream oxygen-sensor diagnosis.
Verify exact sensor position and vehicle fitment before buying.
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Fitment Required · Vehicle-fitment part
Commonly relevant for misfire, ignition-efficiency, and some drivability-related repairs.
Misfire and ignition-related faults commonly involve spark plugs as part of the repair path.
Check the correct plug type, gap, and engine application for your vehicle.
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Fitment Required · Vehicle-fitment part
Relevant when the fault points toward ignition-coil performance or cylinder-specific ignition issues.
Some ignition faults involve coil performance or cylinder-specific coil problems.
Match the coil to your engine and confirm the failed component before ordering.
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.