Car Diagnostic Tools replace the MAF sensor.

How you can Troubleshoot a P0171 Engine Code 1Attach the scan tool and commence the engine. Let the engine to run to operating temperature. Together with the engine operating, visually inspect the engine for apparent vacuum leaks. Listen for hissing, which indicates a vacuum leak specially on bank 1. Bank 1 will be the side with the engine which has the No. 1 spark plug. Refer to your service manual for this facts.

2Attach your scan tool and enter the information stream diagnostic mode. Observe O2 sensor data, and MAF sensor data. Take away a vacuum line from the engine while observing the O2 sensor for a adjust. It should really momentarily study lean—more than 1/2 volt—and then settle into its normal switching mode. If the sensor stays lean, replace the sensor. This is called a lazy O2 sensor and is a common cause for code P0171.3Observe the MAF sensor data Professional diagnositic tools. Take away the MAF sensor from the sensor housing in the intake duct or air filter housing, using a T-15 Torx driver.

Clean the MAF sensor, using MAF sensor cleaner spray Car Diagnostic Tools. Reinstall the MAF sensor and start off the engine. Observe the MAF sensor information for any alter in sensor reading. A dirty MAF sensor is also a common cause of a code P0171 and is usually fixed by cleaning it. If vacuum leaks and O2 sensors have been eliminated as the actual cause and cleaning the MAF doesn't fix the problem, replace the MAF sensor.