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P1166 2003 Infiniti G35 Code - Heated Oxygen Sensor 2 Minimum Voltage Monitoring Bank 2

Quick Answer

The Heated Oxygen Sensor 2 (HO2S) (Rear O2 Sensor), after three way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. Common causes include Faulty heated oxygen (O2) sensor 2 (rear), Intake air leaks, Heated oxygen (O2) sensor 2 (rear) harness is open or shorted. 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: P1166 2003 Infiniti G35 indicates Heated Oxygen Sensor 2 Minimum Voltage Monitoring Bank 2.
Common causes: Common causes include Faulty heated oxygen (O2) sensor 2 (rear), Intake air leaks, Heated oxygen (O2) sensor 2 (rear) harness is open or shorted.
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 2,075

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 Apr 01, 2024

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P1166 2003 Infiniti G35 Description

The Heated Oxygen Sensor 2 (HO2S) (Rear O2 Sensor), after three way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. For optimum catalyst operation, the air fuel mixture (air-fuel ratio) must be maintained near the ideal stoichiometric ratio. The HO2S output voltage changes suddenly in the vicinity of the stoichiometric ratio. The Engine Control Module (ECM) adjusts the fuel injection time so that the air-fuel ratio is nearly stoichiometric. The HO2S generates a voltage between 0.1 and 0.9 V in response to oxygen in the exhaust gas. If the oxygen in the exhaust gas increases, the air-fuel ratio becomes Lean. The ECM interprets Lean when the HO2S voltage is below 0.45 V. If the oxygen in the exhaust gas decreases, the air-fuel ratio becomes Rich. The ECM interprets Rich when the HO2S voltage is above 0.45 V.

OBDII Code P1166 2003 Infiniti G35 - Heated Oxygen Sensor 2 Minimum Voltage Monitoring Bank 2 - AutoCodes.com — P1166 2003 Infiniti G35 Code - Heated Oxygen Sensor 2 Minimum Voltage Monitoring Bank 2

What does this mean?

What are the Possible Causes of the DTC P1166 2003 Infiniti G35?

Faulty heated oxygen (O2) sensor 2 (rear)
Intake air leaks
Heated oxygen (O2) sensor 2 (rear) harness is open or shorted
Heated oxygen (O2) sensor 2 (rear) circuit poor electrical connection
Inappropriate fuel pressure
Faulty fuel injectors

How to Fix the DTC P1166 2003 Infiniti G35?

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 does this mean?

Code Tech Notes

Replacing the O2 Sensor 2 usually takes care of the problem

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P1166 2003 Infiniti G35 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.

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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 P1166 2003 Infiniti G35 Code

1. What does the OBDII code P1166 indicate on a 2003 Infiniti G35?

The code P1166 on a 2003 Infiniti G35 indicates an issue with the Heated Oxygen Sensor 2 Minimum Voltage Monitoring on Bank 2, suggesting that the sensor is not providing the expected voltage output to the engine control unit.

2. What are common symptoms of code P1166 in a 2003 Infiniti G35?

Common symptoms include a check engine light, poor fuel economy, rough engine idle, and possibly a noticeable drop in engine performance.

3. What causes the P1166 code to appear on a 2003 Infiniti G35?

Causes of the P1166 code can include a faulty oxygen sensor, wiring issues related to the sensor (such as shorts or disconnections), or problems with the engine control unit itself.

4. How can I fix the OBDII code P1166 in my 2003 Infiniti G35?

To fix code P1166, inspect and replace the Heated Oxygen Sensor 2 on Bank 2 if it is faulty. Additionally, check the wiring and connectors for damage or corrosion and repair as necessary.

5. Is it safe to drive my 2003 Infiniti G35 with the P1166 code?

While you can technically still drive your vehicle, it is advisable to address the issue promptly as it can lead to increased emissions, reduced fuel efficiency, and potential long-term damage to the engine.

6. How do I locate the Heated Oxygen Sensor 2 on Bank 2 in a 2003 Infiniti G35?

On a 2003 Infiniti G35, Bank 2 typically refers to the side of the engine with cylinders 2, 4, 6, etc. The Heated Oxygen Sensor 2 is usually positioned downstream or behind the catalytic converter on that bank.

7. What tools are needed to replace the oxygen sensor for solving the P1166 code in a 2003 Infiniti G35?

Replacing the oxygen sensor generally requires an O2 sensor socket or a suitable wrench, along with basic hand tools to access and remove the sensor. A digital multimeter may also be helpful for diagnosing wiring issues.

8. How does a faulty oxygen sensor lead to the P1166 code in a 2003 Infiniti G35?

A faulty oxygen sensor can fail to correctly measure the oxygen levels in the exhaust gases, leading to incorrect data being sent to the engine's computer, which in turn can trigger the P1166 code if the voltage falls below a certain threshold.

9. Can a DIY enthusiast fix the P1166 code in a 2003 Infiniti G35, or should it be taken to a professional?

A DIY enthusiast with some automotive repair knowledge can tackle replacing an oxygen sensor. However, if the issue involves complex electrical diagnostics or if the problem persists after replacing the sensor, it is advisable to consult a professional mechanic.