Can A Dirty Air Filter Cause A Check Engine Light

What Does Lawmaking P0171 Hateful?

P0171 definition : Bank 1 has too much air or non enough fuel
Issue Severity: MODERATE– Extended driving with this code can cause internal engine harm.
Repair Urgency: Get this code fixed as shortly as possible to avoid damage to spark plugs, pistons, and catalytic converters.
Diagnosis: It is important to consummate the entire diagnostic process when diagnosing P0171. Many people volition replace the air-fuel sensor or oxygen sensor as soon equally they get a bad reading, merely the root cause tin can also exist a dingy or faulty mass airflow sensor or vacuum leak, thus causing the O2 or MAF sensor to read differently to recoup.

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Combustion engines run most efficiently when they maintain an air-fuel mixture ratio of xiv.7 parts air to ane function fuel. Besides much fuel and/or too petty air results in the engine running rich setting a P0172 trouble code, while likewise little fuel and/or besides much air results in the engine running lean resulting in a check engine light for the P0171 code. The lean condition can exist caused past a vacuum leak, which introduces more air into the air-fuel mixture, or past a weak fuel organization, which does not input enough fuel into the air-fuel mixture. To proceed the engine running properly, the powertrain command module (PCM) tries to recoup for the lean condition by injecting more than fuel to the mixture in an effort to maintain the proper 14.7:1 ratio. When these adjustments get too big, the P0171 code is triggered.

P0171 Causes

Faulty or dirty mass airflow sensor
Vacuum leaks – PCV hoses, vacuum hoses, intake manifold gasket.
Weak fuel pump
Clogged or dirty fuel injectors
Clogged fuel filter
Exhaust leak
Faulty oxygen sensor
Faulty air-fuel ratio sensor

P0171 Symptoms

Check Engine Lite is on or flashing
Lack of ability from the engine
Crude idle
Engine "cough" or misfiring
Tip of spark plugs are white
Commonly associated with error codes: P0174

How Do I Ready Lawmaking P0171?

With a P0171 code, the offset step is to become information technology properly diagnosed to figure out what is causing the engine to run lean. Using the alive data office of the FIXD sensor and app allows you to read and analyze fuel trims to properly diagnose a P0171 lawmaking.

If your engine is running lean and you lot're not comfortable diagnosing this result at home, nosotros recommend finding a RepairPal-certified store to pinpoint the problem and give an accurate estimate for repairs.

These shops can not only help yous figure out what'due south going wrong before you waste fourth dimension and money on the wrong parts, merely they also offer a minimum 12-month, 12,000-mile warranty and stand up backside all their estimates with guaranteed fair pricing.

> Notice a RepairPal Certified Shop Near You

How Much Does It Cost to Fix Code P0171?

If you take your motorcar to a store for diagnosis, near shops will start with an hr of "diag time" (the fourth dimension spent in labor diagnosing your specific issue). Depending on the shop's labor rate, this typically costs somewhere between $75-$150. Many, if not most, shops volition utilize this diagnosis fee to any required repairs if you have them perform the repairs for yous. From there, a shop will be able to give you an authentic estimate for repairs to set your P0171 code.

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Possible Repair Costs for P0171

For fault code P0171, one or more of the beneath repairs may be needed to solve the underlying consequence. For each possible repair, the estimated cost of repair includes the toll of the relevant parts and the cost of labor required to make the repair.

Vacuum leak $100-$200
Clean MAF $100
Replace MAF $300
Fuel Pump $1300-$1700
Fuel pressure level regulator $200-$400
Exhaust repair $100-$200 (if welded to repair)
Air fuel sensor or oxygen sensor $200-$300

DIY Steps to Diagnose Code P0171

If you'd like to try to fix code P0171 at home without throwing money at parts, you'll want to follow the steps below for proper diagnosis. Continue in mind this is an intermediate-level diagnosis and repair and non recommended for beginners. Diagnosis requires more specialized equipment beyond what the FIXD Sensor can provide and it can exist a time and labor-intensive procedure for inexperienced DIYers.

DIY difficulty level: Intermediate

This repair requires mechanical knowledge and is not recommended for beginners.

Tools/parts needed (our top picks from Amazon):

FIXD
Mass Air Flow Cleaner
Fuel Pressure Testing Approximate
Screwdriver
Pliers

Footstep i: Utilise FIXD TO ENSURE NO OTHER ENGINE CODES ARE Nowadays.

Use FIXD to scan your vehicle to verify P0171 is the only code present. If other codes are present, they must be addressed commencement.

Pace 2: INSPECT VACUUM LINES.

Audit all vacuum lines and hoses for leaks, and brand certain they are properly connected. If a leak is nowadays, yous will hear a hissing sound, though it may exist difficult to hear with the engine running. If yous suspect a vacuum leak just are having problem finding it, cheque out this detailed guide to finding vacuum leaks.

STEP iii: Audit MASS AIR Flow (MAF) SENSOR.

Remove the mass airflow sensor and make clean the sensor using mass air flow cleaner or contact cleaner.

> How to clean your MAF sensor

Footstep 4: Inspect Exhaust Arrangement.

Check the exhaust system components for leaks earlier the Air Fuel Ratio Sensors or Oxygen sensors; if you discover any leaks have them repaired. Exhaust leaks can usually be spotted visually by a buildup of soot in the general vicinity of the leak.

Step v: Check FUEL PRESSURE.

Low fuel pressure can throw off the air-fuel mixture ratio, and this could be caused by annihilation from the fuel injectors and fuel pressure level regulator to the fuel pump.

> How to check fuel pressure level

Check fuel injectors: Brand sure the fuel injectors are operation properly and activating. Random misfires tin be a sign of faulty or clogged fuel injectors that need to exist replaced. Too, cheque that the fuel injector wiring is not damaged and is continued properly.

> How to check fuel injectors by ear

> How to check fuel injectors with a digital multimeter

Step 6: Supercede AIR-FUEL AND/OR O2 SENSORS

At this point if the code still persists you lot may want to consider replacing your A/F sensor or O2 sensors.

Footstep 7: Inspect AND Supersede SPARK PLUGS

Later on you repair the cause of your P0171 code, inspect the spark plugs. If in that location is a white haze or chaff on the tip of the spark plugs (near the diode that screws into the engine), then you should supervene upon all of the spark plugs .

Common P0171 diagnosis mistakes

Information technology is important to complete the entire diagnostic process when diagnosing P0171. Many people volition replace the air-fuel sensor or O2 sensor as soon every bit they get a bad reading, merely the root cause is often a dirty or faulty mass airflow sensor or vacuum leak, thus causing the O2 or A/F sensor to read differently to compensate. Reading and analyzing fuel trims and the freeze frame information is the key to properly diagnosing P0171.

Still Need Aid Fixing Code P0171?

If you've followed the steps in a higher place and are nonetheless experiencing a lean engine condition and code P0171, please contact the FIXD Mechanic Hotline if you're a FIXD Premium subscriber or find a RepairPal certified shop near you to get the right repairs at a fair price.