AutoCodes – BMW – P0157 BMW

P0157 BMW Code - O2 Sensor Circuit Low Voltage Bank 2 Sensor 2

Quick Answer

The heated oxygen sensor 2 (HO2S), after three way catalyst (manifold), monitors the oxygen level in the exhaust gas on each bank. Common causes include Faulty Rear Heated Oxygen Sensor Bank 2, Rear Heated Oxygen Sensor Bank 2 harness is open or shorted, Rear Heated Oxygen Sensor Bank 2 circuit poor electrical connection. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means: P0157 BMW indicates O2 Sensor Circuit Low Voltage Bank 2 Sensor 2.
Common causes: Common causes include Faulty Rear Heated Oxygen Sensor Bank 2, Rear Heated Oxygen Sensor Bank 2 harness is open or shorted, Rear Heated Oxygen Sensor Bank 2 circuit poor electrical connection.
Severity: Moderate - service should be scheduled soon.
Can I drive?: The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

Save to My Repairs My Repairs

AI answers can be wrong. Verify repairs with testing. Open full chat

Code Popularity 7,972

How popular is this code, among other codes? Low

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Intermediate (2 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jun 14, 2020

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
Add Comment

💬 Need more help? Ask Coddy for instant answers — it's free!

Code P0157 BMW Description

The heated oxygen sensor 2 (HO2S), 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 P0157 BMW - O2 Sensor Circuit Low Voltage Bank 2 Sensor 2 - AutoCodes.com — P0157 BMW Code - O2 Sensor Circuit Low Voltage Bank 2 Sensor 2

What does this mean?

What are the Possible Causes of the DTC P0157 BMW?

Faulty Rear Heated Oxygen Sensor Bank 2
Rear Heated Oxygen Sensor Bank 2 harness is open or shorted
Rear Heated Oxygen Sensor Bank 2 circuit poor electrical connection
Inappropriate fuel pressure
Faulty fuel injectors
Intake air leaks may be faulty
Exhaust gas leaks

How to Fix the DTC P0157 BMW?

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 Rear Heated Oxygen Sensor Bank 2 usually takes care of the problem.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0157 BMW 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 P0157 BMW code?

Need more information on how to fix the P0157 BMW code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0157 BMW code diagnosed by a professional: Find a repair shop in your area

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 P0157 BMW Code

1. What are the common symptoms of OBDII code P0157 on a BMW?

- Common symptoms include poor fuel economy, rough idling, engine misfires, and an illuminated check engine light.

2. What does the O2 Sensor Circuit Low Voltage Bank 2 Sensor 2 error code mean for a BMW?

- This code indicates that the oxygen sensor located in the second bank of cylinders, after the catalytic converter, is detecting a lower than normal voltage.

3. What are the possible causes of P0157 code on a BMW?

- Possible causes include a faulty oxygen sensor, damaged wiring or connectors, exhaust leaks, a malfunctioning catalytic converter, or issues with the engine's computer system.

4. How can I diagnose the O2 Sensor Circuit Low Voltage Bank 2 Sensor 2 error code on my BMW?

- Diagnosis typically involves using a scan tool to read the code, inspecting the oxygen sensor and its wiring, checking for exhaust leaks, and testing the sensor's voltage output.

5. Can I drive my BMW with the P0157 code present?

- It is not recommended to drive your BMW with this code present, as it can lead to decreased fuel efficiency and potential damage to the catalytic converter over time.

6. How can I repair the O2 Sensor Circuit Low Voltage Bank 2 Sensor 2 issue on my BMW?

- Repair options may include replacing the oxygen sensor, repairing damaged wiring or connectors, fixing exhaust leaks, or addressing any other underlying issues causing the low voltage reading.

7. Will resetting the check engine light fix the P0157 code on my BMW?

- Resetting the check engine light may temporarily clear the code, but it will likely return if the underlying issue causing the low voltage reading is not addressed.

8. How much does it cost to repair the OBDII code P0157 on a BMW?

- The cost of repairing this code can vary depending on the exact cause of the issue, but it may involve parts and labor costs for replacing the oxygen sensor or addressing other related components.

9. Can a DIY enthusiast fix the P0157 code on a BMW?

- Depending on your skill level and access to tools, it may be possible to address this code yourself by replacing the oxygen sensor or repairing wiring issues. However, professional diagnosis and repair are recommended for accurate and lasting solutions.

10. How often should the oxygen sensors be inspected and replaced on a BMW to prevent O2 sensor-related issues like P0157?

- It is generally recommended to inspect and replace oxygen sensors every 60,000 to 90,000 miles to prevent issues like the P0157 code from occurring. Regular maintenance can help ensure proper engine performance and emissions control.