AutoCodes – Generic – P1157

P1157 Code - Air/Fuel Ratio Sensor 1 Range/Performance Problem

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 Sensor 1, Air/Fuel Ratio Sensor 1 harness is open or shorted, Air/Fuel Ratio 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: P1157 indicates Air/Fuel Ratio Sensor 1 Range/Performance Problem.
Common causes: Common causes include Faulty Air/Fuel Ratio Sensor 1, Air/Fuel Ratio Sensor 1 harness is open or shorted, Air/Fuel Ratio 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 40,546

How popular is this code, among other codes? Medium

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 03, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P1157 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 P1157 - Air/Fuel Ratio Sensor 1 Range/Performance Problem - AutoCodes.com — P1157 Code - Air/Fuel Ratio Sensor 1 Range/Performance Problem

What does this mean?

What are the Possible Causes of the DTC P1157?

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

How to Fix the DTC P1157?

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 P1157 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 P1157 code?

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Information for Specific Makes

P1157 Acura — Air/Fuel Ratio Sensor 1 Range/Performance Problem
P1157 Audi — Manifold Absolute Pressure Sensor Supply Voltage
P1157 BMW — O2 Sensor Heater Circuit High Voltage Bank 2 Sensor 2
P1157 Buick — HO2S Bank 2 Sensor 2 Lean System Or Low Voltage
P1157 Cadillac — HO2S Bank 2 Sensor 2 Lean System Or Low Voltage
P1157 Chevrolet — HO2S Bank 2 Sensor 2 Lean System Or Low Voltage
P1157 Ford — Lack Of Heated Oxygen Sensor Switches Bank 2 Sensor 2 Indicates Lean
P1157 GMC — HO2S Bank 2 Sensor 2 Lean System Or Low Voltage
P1157 Honda — Air/Fuel Ratio Sensor 1 Range/Performance Problem
P1157 Lincoln — Lack Of Heated Oxygen Sensor Switches Bank 2 Sensor 2 Indicates Lean
P1157 Mazda — HO2S-12 Circuit Condition
P1157 Mercury — Lack Of Heated Oxygen Sensor Switches Bank 2 Sensor 2 Indicates Lean
P1157 MINI — O2 Sensor Heater Circuit High Voltage Bank 2 Sensor 2
P1157 Volkswagen — Manifold Absolute Pressure Sensor Supply Voltage

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.