AutoCodes – Acura – P0172 Acura

P0172 Acura Code - Fuel System Too Rich Bank 1

Quick Answer

The Powertrain Control Module (PCM) detects the oxygen content in the exhaust gas from the Air/Fuel Ratio (A/F) Sensor (Sensor 1) signal voltage, and it uses fuel feedback control to maintain the optimal air/fuel ratio. Common causes include Faulty Fuel Pump, Faulty Fuel Injector, Fuel Pressure Regulator. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P0172 Acura indicates Fuel System Too Rich Bank 1.
Common causes: Common causes include Faulty Fuel Pump, Faulty Fuel Injector, Fuel Pressure Regulator.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 38,160

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Aug 14, 2023

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P0172 Acura Description

The Powertrain Control Module (PCM) detects the oxygen content in the exhaust gas from the Air/Fuel Ratio (A/F) Sensor (Sensor 1) signal voltage, and it uses fuel feedback control to maintain the optimal air/fuel ratio. The air/fuel ratio coefficient for correcting the amount of injected fuel is the short-term fuel trim. The PCM varies short-term fuel trim continuously to keep the air/fuel ratio close to the stoichiometric ratio for all driving conditions. Long-term fuel trim is computed from short-term fuel trim and is used to regulate long-term deviation from the stoichiometric air/fuel ratio, which occurs when fuel metering components deteriorate with age or system failures occur. In addition, long-term fuel trim is stored in the PCM memory and is used to determine when fuel metering components malfunction. When long-term fuel trim is higher than normal, which is about 1 (0 %), the amount of injected fuel must be increased, and when lower than normal, it must be decreased. If long-term fuel trim is normal (too rich) or less, the PCM detects a malfunction in the fuel metering components and stores a Diagnostic Trouble Code (DTC).

OBDII Code P0172 Acura - Fuel System Too Rich Bank 1 - AutoCodes.com — P0172 Acura Code - Fuel System Too Rich Bank 1

What does this mean?

What are the Possible Causes of the DTC P0172 Acura?

Faulty Fuel Pump
Faulty Fuel Injector
Fuel Pressure Regulator
Fuel line failure
Fuel supply system failure
Faulty Mass Air Flow (MAF) Sensor
Faulty Manifold Absolute Pressure (MAP) Sensor
Faulty A/F Sensor (Sensor 1)
Faulty Secondary HO2S (Sensor 2)
Vacuum hose mis installed
Throttle body air leak
Intake manifold air leak
Faulty EVAP Canister Purge Valve

How to Fix the DTC P0172 Acura?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0172 Acura code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P0172 Acura code?

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.