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 when you take your foot off the gas pedal, the car's computer thinks there's too much air pressure in the engine. It's like when you blow too much air into a balloon and it gets too tight.
The P1109 code indicates that the manifold air pressure (MAP) sensor is reading a higher than expected pressure during deceleration.
The MAP sensor measures the pressure inside the intake manifold. During deceleration, the pressure should decrease. If the sensor reads a pressure that's too high, it triggers the P1109 code. This could be due to a faulty sensor, a vacuum leak, or an issue with the engine control module (ECM).
• Check Engine Light is on
• Poor fuel economy
• Rough idling
• Faulty MAP sensor
• Vacuum leak in the intake manifold
• Faulty engine control module (ECM)
MAP Sensor: A sensor that measures the pressure inside the intake manifold.
ECM: Engine Control Module, the computer that controls engine functions.
• Use an OBD-II scanner to confirm the code.
• Inspect the MAP sensor and its wiring for damage.
• Check for vacuum leaks in the intake manifold.
• Replace the faulty MAP sensor.
• Repair any vacuum leaks.
• Reprogram or replace the ECM if necessary.
• OBD-II scanner
• Multimeter
• Vacuum gauge
$100 - $300
Moderate
• Honda Accord
• Toyota Camry
• Ford F-150
• Regular maintenance and inspection of the intake system.
• Ensure all sensors are clean and functioning.
• Perform routine checks for vacuum leaks.
Sensor Issue
• Have the vehicle inspected by a professional if the Check Engine Light is on.
• Avoid driving aggressively to prevent further issues.
Check with your vehicle manufacturer for warranty coverage on engine sensors.
This code is relatively common in older vehicles with high mileage or those that have not been regularly maintained.
Moderate – Addressing this issue can prevent further engine performance problems.
Driving with a faulty MAP sensor can lead to increased emissions and may not comply with local environmental regulations.
• Engine at operating temperature
• Vehicle decelerating from a higher speed
The MAP sensor is typically located on or near the intake manifold.
Q: Can I drive with a P1109 code?
A: It's possible to drive for a short period, but it's best to fix the issue soon to avoid further engine problems.
Q: How do I know if my MAP sensor is bad?
A: Symptoms of a bad MAP sensor include rough idling, poor fuel economy, and a Check Engine Light.
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