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 is having trouble adjusting the fuel mixture for one side of the engine. It's like trying to make a perfect smoothie but not having enough fruit to balance the taste.
The P1158 code is triggered when the engine control module (ECM) detects that the fuel trim adaptation for Bank 1 is lower than expected. This means the ECM is unable to add enough fuel to maintain the correct air-fuel mixture.
The ECM monitors the air-fuel ratio and adjusts the fuel trim to maintain optimal engine performance. If the additive fuel trim on Bank 1 is too low, it indicates that the ECM is unable to inject enough fuel to compensate for a lean condition. This can be caused by issues such as vacuum leaks, faulty sensors, or fuel delivery problems.
• Check Engine Light is on
• Poor fuel economy
• Rough engine idle
• Vacuum leak in the intake manifold
• Faulty mass air flow (MAF) sensor
• Fuel injector issues
ECM: Engine Control Module
MAF Sensor: Mass Air Flow Sensor
• Use an OBD-II scanner to confirm the code.
• Check for vacuum leaks in the intake system.
• Test the mass air flow sensor for proper operation.
• Repair any vacuum leaks found.
• Clean or replace the mass air flow sensor.
• Inspect and clean fuel injectors.
• OBD-II scanner
• Vacuum leak detector
• Multimeter
$100 - $300
Moderate
• Toyota Camry
• Honda Accord
• Ford Focus
• Regularly check and replace air filters.
• Perform routine maintenance on the fuel system.
• Inspect vacuum hoses for leaks.
Engine Performance
• Do not ignore the Check Engine Light.
• Have your vehicle inspected by a professional if you notice symptoms.
• Maintain regular vehicle service intervals.
Check with your vehicle's manufacturer for warranty coverage on emission-related components.
This code has been commonly associated with vehicles experiencing lean conditions due to unmetered air entering the engine.
Moderate – This issue should be addressed soon to prevent potential engine damage.
Driving with a lean condition can increase emissions and may not comply with local emissions regulations.
• Engine at operating temperature
• Vehicle in closed-loop operation
The components related to this code, such as the MAF sensor and intake manifold, are typically located in the engine bay.
Q: Can I drive with a P1158 code?
A: It's possible to drive short distances, but it's best to address the issue soon to avoid engine damage.
Q: Will a P1158 code affect my car's performance?
A: Yes, it can lead to poor fuel economy and rough idling.
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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.