AutoCodes – Honda – P1172 2008 Honda Accord

P1172 2008 Honda Accord Code - Rear A/F Sensor Bank 1 Sensor 1 Circuit Out Of Range High

Quick Answer

The Air/Fuel Ratio (A/F) sensor 1 is installed in the exhaust system and detects oxygen content in the exhaust gas. Common causes include Faulty Air/Fuel Ratio Bank 1 Sensor 1, Air/Fuel Ratio Bank 1 Sensor 1 harness is open or shorted, Air/Fuel Ratio Bank 1 Sensor 1 circuit poor electrical connection. 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: P1172 2008 Honda Accord indicates Rear A/F Sensor Bank 1 Sensor 1 Circuit Out Of Range High.
Common causes: Common causes include Faulty Air/Fuel Ratio Bank 1 Sensor 1, Air/Fuel Ratio Bank 1 Sensor 1 harness is open or shorted, Air/Fuel Ratio Bank 1 Sensor 1 circuit poor electrical connection.
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 5,731

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on May 16, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1172 2008 Honda Accord Description

The Air/Fuel Ratio (A/F) sensor 1 is installed in the exhaust system and detects oxygen content in the exhaust gas. The A/F sensor transmits output voltage to the Engine Control Module (ECM). A heater for the sensor element is embedded in the A/F sensor (sensor 1). It is activated and heats the sensor to stabilize and speed the detection of oxygen content by controlling current flowing through the heater. An increase in the current levels off as the applied voltage to the element electrode reaches a certain range because the amount of oxygen which is led through the diffusion layer is limited. The current amperage is proportional to oxygen content in the exhaust gas, so the air/fuel ratio is detected by the measurement of the current amperage. The ECM compares a set target air/fuel ratio with the detected air/fuel ratio and controls the fuel injection timing.
If the A/F sensor (sensor 1) voltage is low, the air/fuel ratio is lean, and the ECM uses A/F feedback control to issue a Rich command. If the A/F sensor (sensor 1) voltage is high, the air/fuel ratio is rich, and the ECM uses A/F feedback control to issue a Lean command.

OBDII Code P1172 2008 Honda Accord - Rear A/F Sensor Bank 1 Sensor 1 Circuit Out Of Range High - AutoCodes.com — P1172 2008 Honda Accord Code - Rear A/F Sensor Bank 1 Sensor 1 Circuit Out Of Range High

What does this mean?

What are the Possible Causes of the DTC P1172 2008 Honda Accord?

Faulty Air/Fuel Ratio Bank 1 Sensor 1
Air/Fuel Ratio Bank 1 Sensor 1 harness is open or shorted
Air/Fuel Ratio Bank 1 Sensor 1 circuit poor electrical connection

How to Fix the DTC P1172 2008 Honda Accord?

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 P1172 2008 Honda Accord 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 P1172 2008 Honda Accord 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.

Frequently Asked Questions about P1172 2008 Honda Accord Code

1. What does the OBDII code P1172 mean on a 2008 Honda Accord?

P1172 indicates that the rear air-fuel (A/F) ratio sensor for Bank 1 Sensor 1 is reporting a circuit out-of-range high, meaning the sensor is detecting an unusually lean air-fuel mixture.

2. What are the common symptoms of a P1172 code on a 2008 Honda Accord?

Symptoms may include poor fuel economy, rough idling, hesitation during acceleration, engine misfires, and the check engine light being illuminated.

3. What causes the P1172 code to trigger in a Honda Accord?

Possible causes include a faulty air-fuel ratio sensor, wiring or connector issues, vacuum leaks, a dirty or malfunctioning mass airflow sensor, or problems with the fuel delivery system.

4. Can a faulty air-fuel ratio sensor cause the P1172 code?

Yes, a failing or damaged air-fuel ratio sensor is one of the most common causes of the P1172 code.

5. How do I diagnose the P1172 code on my 2008 Honda Accord?

Start by checking the air-fuel ratio sensor and its wiring for damage or loose connections, inspect for vacuum leaks, and verify the proper functioning of the mass airflow sensor and fuel injectors.

6. Can a vacuum leak cause the P1172 code?

Yes, a vacuum leak can cause an excessively lean air-fuel mixture, which may trigger the P1172 code.

7. Is it safe to drive with a P1172 code on my 2008 Honda Accord?

While the car may still be drivable, ignoring the issue can lead to reduced engine performance, poor fuel economy, and potential long-term damage to the engine or catalytic converter.

8. How do I fix the P1172 code on a Honda Accord?

Repairs may involve replacing the faulty air-fuel ratio sensor, repairing damaged wiring, cleaning or replacing the mass airflow sensor, fixing vacuum leaks, or addressing fuel system issues.

9. How much does it cost to fix the P1172 code on a 2008 Honda Accord?

Costs vary depending on the exact issue. Replacing an air-fuel ratio sensor typically costs between $200 and $400, while addressing wiring or vacuum leaks may cost less.

10. Can a dirty mass airflow sensor cause the P1172 code?

Yes, a dirty or malfunctioning mass airflow sensor can provide inaccurate readings, leading to an incorrect air-fuel mixture and triggering the P1172 code.