What Does P1118 Mean?
P1118 indicates the Mass or Volume Air Flow sensor circuit on Bank 2 is reporting a higher-than-expected signal. In vehicles with dual intake systems or twin-turbo configurations, this sensor measures airflow to Bank 2. A high input reading causes the ECM to calculate excessive air entering the engine, resulting in over-fueling on Bank 2, black smoke, poor fuel economy, and potential catalytic converter damage from running rich.
Common Causes
30%
Bank 2 MAF sensor contaminated or faulty reading high
25%
Short to voltage in the Bank 2 MAF sensor signal wire
18%
Intake system restriction after the Bank 2 MAF sensor (collapsed hose, debris)
15%
Incorrect Bank 2 MAF sensor installed (wrong part number or calibration)
12%
ECM calibration issue or software fault on Bank 2 MAF input
Diagnostic Steps
1
Step 1: Monitor Bank 2 MAF sensor reading (g/s) at idle and compare to Bank 1. Both banks should read similarly at idle. A significantly higher Bank 2 reading indicates a sensor or circuit fault.
2
Step 2: Inspect the Bank 2 air intake duct for collapsed hoses, debris, or restrictions that could create turbulent airflow past the sensor, causing false high readings.
3
Step 3: Disconnect the Bank 2 MAF sensor and check for voltage on the signal wire. With the sensor unplugged, there should be no signal voltage — any voltage present indicates a short to power.
4
Step 4: Clean the Bank 2 MAF sensor element with MAF-specific cleaner. Contamination from oil or dirt can cause the hot wire/film to read high.
5
Step 5: Verify the correct part number MAF sensor is installed for Bank 2. Cross-application of sensors with different calibrations is a common cause of high readings.
6
Step 6: Replace the Bank 2 MAF sensor if cleaning does not resolve the high reading. Clear codes and verify both banks track similarly during a road test.
Estimated Repair Cost
$100 - $400
Parts + labor, varies by vehicle and location
P1118 indicates the Mass or Volume Air Flow sensor circuit on Bank 2 is reporting a higher-than-expected signal. In vehicles with dual intake systems or twin-turbo configurations, this sensor measures airflow to Bank 2. A high input reading causes the ECM to calculate excessive air entering the engi...
The most common cause of P1118 (Mass Or Volume Air Flow Circuit High Input (Bank 2)) is: Bank 2 MAF sensor contaminated or faulty reading high
Typical repair costs for P1118 range from $100 to $400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Excessive fueling on one bank can cause catalytic converter overheating, which in extreme cases presents a fire risk. Rich running also increases carbon monoxide emissions and reduces engine performance.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1118 to identify the root cause.
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Quick Info
Category
Powertrain
System
Engine Management / Air Metering (Bank 2)
Difficulty
Type
Manufacturer
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