P0173 Possible Causes
- Intake air leaks
- Faulty front heated oxygen sensor
- Ignition misfiring
- Faulty fuel injectors
- Exhaust gas leaks
- Incorrect fuel pressure
- Lack of fuel
- Faulty Mass Air Flow (MAF) sensor
- Incorrect Positive Crankcase Ventilation (PCV) hose connection
First diagnose P0173 code
Check the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.
P0173 Tech NotesDirty air filter of faulty air flow sensor are common causes for the P0173 code of the problem.
Cost of diagnosing the P0173 code
Labor: 1.0The cost of diagnosing the P0173 code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle's make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
When is the P0173 code detected?- Fuel injection system does not operate properly.
- The amount of mixture ratio compensation is not correct
P0173 Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Excessive Fuel Consumption
P0173 DescriptionWith the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the theoretical mixture ratio based on the mixture ratio feedback signal from the heated oxygen sensors 1. The Engine Control Module (ECM) calculates the necessary compensation to correct the offset between the actual and the theoretical ratios.
In case the amount of the compensation value is extremely large (The actual mixture ratio is too lean.), the ECM judges the condition as the fuel injection system malfunction and light up the MIL (2 trip detection logic).
P0173 More InformationNeed more information on how to fix the P0173 code?
Get Access to Factory Service Manuals
P0173 Information for specific makes
- P0173 BMW Fuel Trim Malfunction Bank 2
- P0173 CHRYSLER Fuel System 2/1 Rich Control Over Limit
- P0173 DODGE Fuel System 2/1 Rich Control Over Limit
- P0173 HYUNDAI Fuel Trim Bank 2
- P0173 JEEP Fuel System 2/1 Rich Control Over Limit
- P0173 KIA Fuel Trim Bank 2
- P0173 MAZDA Bank 2 Adaptive Fuel Table At Calibrated Limit
- P0173 MERCEDES-BENZ Fuel Trim Malfunction Bank 2
- P0173 MITSUBISHI Fuel Trim Malfunction Bank 2
Need more help?Get the P0173 code diagnosed by a professional: Find a repair shop in your area
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