AutoCodes – Saturn – P0157 Saturn

P0157 Saturn Code - HO2S Circuit Low Voltage Bank 2 Sensor 2

Quick Answer

The Heated Oxygen Sensors (HO2S) are used for fuel control and catalyst monitoring. 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 Saturn indicates HO2S 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.

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Code Popularity 7,252

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 May 27, 2022

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0157 Saturn Description

The Heated Oxygen Sensors (HO2S) are used for fuel control and catalyst monitoring. Each HO2S compares the oxygen content of the surrounding air with the oxygen content of the exhaust stream. When the engine is started, the Engine Control Module (ECM) operates in an Open Loop mode, ignoring the HO2S signal voltage while calculating the air-to-fuel ratio. While the engine runs, the HO2S heats up and begins to generate a voltage within a range of 0 - 1, 000 mV. Once sufficient HO2S voltage fluctuation is observed by the ECM, Closed Loop is entered. The ECM uses the HO2S voltage to determine the air-to-fuel ratio. An HO2S voltage that increases toward 1, 000 mV indicates a rich fuel mixture. An HO2S voltage that decreases toward 0 mV indicates a lean fuel mixture.
The heating elements inside each HO2S heat the sensor to bring the sensor up to operating conditions faster. This allows the system to enter Closed Loop earlier and the ECM to calculate the air-to-fuel ratio sooner.
The Diagnostic Trouble Code (DTC) will be set when the ECM detects that the heated oxygen sensor is shorted to ground if the HO2S voltage is less than 50 mV.

OBDII Code P0157 Saturn - HO2S Circuit Low Voltage Bank 2 Sensor 2 - AutoCodes.com — P0157 Saturn Code - HO2S Circuit Low Voltage Bank 2 Sensor 2

What does this mean?

What are the Possible Causes of the DTC P0157 Saturn?

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
Low or high fuel system pressure
Fuel contamination
Faulty fuel injectors
Exhaust gas leaks
Engine vacuum leaks

How to Fix the DTC P0157 Saturn?

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 (HO2S) Bank 2 usually takes care of the problem.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0157 Saturn 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 Saturn 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 P0157 Saturn Code

1. What are common symptoms of OBDII code P0157 in a Saturn vehicle?

- Common symptoms include poor fuel economy, rough idling, engine misfires, and the illumination of the Check Engine Light.

2. What does the OBDII code P0157 on a Saturn indicate about the HO2S circuit?

- The code indicates low voltage in the Bank 2 Sensor 2 oxygen sensor circuit, which can affect the engine's air-fuel mixture.

3. What are some possible causes of the P0157 code in a Saturn's HO2S circuit?

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

4. How can I diagnose the OBDII code P0157 in my Saturn?

- Diagnosis typically involves using an OBDII scanner to retrieve the code, inspecting the oxygen sensor and related components, and testing the circuit for voltage irregularities.

5. Can I continue driving my Saturn with the P0157 code present?

- It is not recommended to drive your vehicle with the P0157 code, as it can lead to decreased fuel efficiency and potential damage to the engine over time.

6. How can I repair the OBDII code P0157 in my Saturn?

- Repair options include replacing the Bank 2 Sensor 2 oxygen sensor, repairing damaged wiring or connectors, fixing exhaust leaks, or addressing any issues with the engine's computer system.

7. Is it possible to reset the Check Engine Light after repairing the P0157 code in a Saturn?

- Yes, after repairing the underlying issue causing the code, you can reset the Check Engine Light using an OBDII scanner or by disconnecting the car's battery for a few minutes.

8. How much does it typically cost to fix the P0157 code in a Saturn at a repair shop?

- The cost of fixing the P0157 code can vary depending on the specific issue, but it may range from $100 to $300 for parts and labor at a repair shop.

9. Are there any preventive measures to avoid the P0157 code in a Saturn?

- Regular maintenance, such as inspecting and replacing oxygen sensors as recommended, checking for exhaust leaks, and keeping the engine well-tuned, can help prevent the occurrence of the P0157 code.

10. Can a DIY enthusiast with basic automotive knowledge fix the P0157 code in a Saturn?

- Depending on the exact cause of the code, a DIY enthusiast with some knowledge of automotive repairs may be able to address the issue themselves by following repair guides or tutorials.