P0058 H02S Heater Control Circuit High (Bank 2 Sensor 2)

Introduction:

The diagnostic trouble code (DTC) P0058 indicates a fault within the heater control circuit of the Bank 2, Sensor 2 oxygen sensor (O2 sensor) in your vehicle's exhaust system. This code signals that the engine control unit (ECU) has detected a voltage reading in the heater control circuit that is higher than expected. Addressing this issue promptly is crucial for maintaining optimal fuel efficiency, reducing emissions, and preventing potential damage to the catalytic converter.

Comprehensive Table: P0058 Details

Detailed Explanations

Code Definition: H02S Heater Control Circuit High (Bank 2 Sensor 2)

This diagnostic trouble code (DTC) indicates that the Engine Control Unit (ECU), also sometimes called the Powertrain Control Module (PCM), has detected an abnormally high voltage in the heater control circuit of the downstream oxygen sensor (Sensor 2) on Bank 2 of the engine. The "high" designation means the voltage is exceeding the expected range, suggesting a potential short to voltage or a problem within the sensor's heater circuit itself. This issue prevents the sensor from reaching its optimal operating temperature quickly.

Location: Bank 2, Sensor 2 (Downstream Oxygen Sensor)

Locating the correct sensor is critical for accurate diagnosis and repair. "Bank 2" refers to the side of the engine opposite cylinder number one. The configuration of the engine (inline, V-type, etc.) determines which side is Bank 2. "Sensor 2" is the downstream sensor, situated after the catalytic converter on Bank 2. This sensor monitors the exhaust gases exiting the catalytic converter to determine its effectiveness.

Function of Sensor: Monitors Catalytic Converter Efficiency

The Bank 2, Sensor 2 oxygen sensor plays a crucial role in monitoring the performance of the catalytic converter on Bank 2. By measuring the oxygen content in the exhaust stream after it has passed through the converter, the ECU can assess whether the converter is effectively reducing harmful emissions. The heater element in the sensor helps it reach operating temperature quickly, especially during cold starts, allowing for accurate readings.

Heater Function: Rapidly Reaching Operating Temperature

Oxygen sensors require a specific operating temperature (around 600°F or 315°C) to function accurately. The heater element within the sensor is designed to quickly bring the sensor to this temperature, especially during cold starts when the exhaust gas temperature is low. This ensures that the ECU receives accurate data, enabling it to properly adjust the air/fuel mixture and optimize engine performance. Without a properly functioning heater, the sensor will take longer to reach operating temperature, leading to inaccurate readings and potential performance issues.

Typical Symptoms: Check Engine Light, Reduced Fuel Economy, Failed Emissions Test

The most common symptom of a P0058 code is the illumination of the Check Engine Light on the dashboard. Other symptoms may include a noticeable decrease in fuel economy, potentially leading to more frequent trips to the gas station. Furthermore, the vehicle may fail an emissions test due to the malfunctioning oxygen sensor affecting the catalytic converter's efficiency and increasing harmful emissions. In some cases, the engine may exhibit rough idling or hesitation, although this is less common.

Diagnostic Steps: Visual Inspection, Resistance and Voltage Testing, Scan Tool Monitoring

Diagnosing a P0058 code requires a systematic approach. Start with a thorough visual inspection of the wiring and connectors associated with the Bank 2, Sensor 2 oxygen sensor, looking for any signs of damage, corrosion, or loose connections. Next, use a multimeter to test the resistance of the heater circuit within the sensor itself, comparing the reading to the manufacturer's specifications. Also, test the voltage at the heater circuit connector to ensure that power is being supplied. Use a scan tool to monitor the O2 sensor data and confirm the heater circuit is not functioning correctly. Finally, check for shorts to voltage in the heater circuit using a multimeter.

Potential Impact of Ignoring: Reduced Fuel Economy, Increased Emissions, Catalytic Converter Damage

Ignoring a P0058 code can lead to several negative consequences. The reduced fuel economy will result in higher fuel costs. Increased emissions contribute to air pollution and could result in failing future emissions tests. More seriously, the improper air/fuel mixture caused by the malfunctioning oxygen sensor can potentially damage the catalytic converter over time, leading to a costly repair.

Related Codes: P0052, P0050, P0056

Several other diagnostic trouble codes are related to the P0058 code. P0052 indicates a "Heater Control Circuit Low" condition for Bank 2, Sensor 2, suggesting a different type of electrical fault. P0050 refers to the heater control circuit for Bank 2, Sensor 1 (the upstream oxygen sensor). P0056 is another code specifically related to the heater circuit on Bank 2, Sensor 2, but it may indicate a different type of malfunction. These codes can provide additional clues to the underlying cause of the problem.

Bank 2 Definition: Side of Engine Opposite Cylinder #1

The term "Bank 2" refers to one side of the engine on vehicles with multiple cylinder banks (such as V-type engines). Crucially, Bank 2 is defined as the side of the engine that does not contain cylinder number one. Determining the exact location of Bank 2 requires consulting your vehicle's repair manual or engine diagram, as it varies depending on the engine configuration.

Sensor 2 Definition: Downstream Sensor After Catalytic Converter

"Sensor 2" specifically refers to the downstream oxygen sensor located after the catalytic converter on a particular bank of the engine (in this case, Bank 2). Its primary function is to monitor the efficiency of the catalytic converter by measuring the oxygen content of the exhaust gases after they have passed through the converter. This information is used by the ECU to assess whether the converter is effectively reducing harmful emissions.

Frequently Asked Questions

• What does the P0058 code mean? The P0058 code signifies a "Heater Control Circuit High" condition on the Bank 2, Sensor 2 oxygen sensor, meaning the ECU has detected a higher-than-expected voltage in the heater circuit. This typically indicates a problem with the sensor's heater element or the wiring associated with it.

• Can I drive with a P0058 code? While you can technically drive with a P0058 code, it's not recommended for extended periods. The malfunctioning O2 sensor can negatively impact fuel economy and emissions, and potentially damage the catalytic converter over time.

• How do I fix a P0058 code? Fixing a P0058 code involves diagnosing the underlying cause, which could be a faulty O2 sensor, wiring issues, or a problem with the ECU. Replacement of the sensor or repair of the wiring is often necessary.

• Is the O2 sensor the same as an air/fuel ratio sensor? While both oxygen sensors and air/fuel ratio sensors measure the oxygen content in the exhaust, they operate on different principles and have different output signals. Air/fuel ratio sensors are typically used upstream of the catalytic converter to provide more precise air/fuel mixture control.

• How much does it cost to fix a P0058 code? The cost to fix a P0058 code can vary depending on the cause of the problem and the labor rates in your area. Replacing the O2 sensor is generally the most common repair, and the cost can range from $100 to $300, including parts and labor.

Conclusion

The P0058 diagnostic trouble code indicates a problem with the heater control circuit of the Bank 2, Sensor 2 oxygen sensor. Prompt diagnosis and repair are essential to maintain optimal fuel efficiency, reduce emissions, and prevent potential damage to the catalytic converter.