Subaru Code P0147 is a common cause of front oxygen sensor 2 (LH) heater circuit malfunction. This code is triggered when the engine is started, running at idle speed, and the PCM detects the HO2S-21 heater current indicated less than 0.2 amps or that it indicated more than 2 amps during the CCM test. Various causes can trigger this malfunction and require a thorough inspection of the system to identify and resolve the issue. To help diagnose the cause of Subaru Code P0147, it is essential to review the output signal from the ECM, the power supply to the front oxygen sensor 2 (LH), and the sensor itself. The following table outlines the possible causes and solutions for Subaru Code P0147.
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Causes and Solutions for Subaru Code P0147
| Cause | Solution |
|---|---|
| Using a scan tool, check the current data | Analyze the data from the scan tool to diagnose the issue. |
| Check the output signal from the ECM | Scan the output signal from the ECM to troubleshoot the issue. |
| Check the power supply to the front oxygen sensor 2 (LH) | Confirm that the power supply is adequate and that the connections are secure. |
| Check the sensor | Replace the sensor if necessary. |
Subaru Code P0147 can be tricky to diagnose, but with the right tools and knowledge, it can be resolved quickly and efficiently. The key is to understand the possible causes, review the output signal from the ECM, verify the power supply to the front oxygen sensor 2 (LH), and inspect the sensor itself. With the proper knowledge and tools, Subaru Code P0147 can be fixed in no time.
Using a Scan Tool to Check Current Data
When a Subaru Code P0147 is triggered, the first thing to do is to use a scan tool to check the current data. This data can provide a lot of insight into what is causing the code to be triggered. It can tell if the PCM is detecting the HO2S-21 heater current at less than 0.2 amps or more than 2 amps during the CCM test. By analyzing this data, the technician can identify the root cause of the code and take the necessary steps to fix the issue.
Checking the Output Signal from the ECM
The output signal from the ECM is another essential factor to consider when diagnosing Subaru Code P0147. The technician can use a scan tool to scan the output signal from the ECM and determine if there is a problem. If the output signal is not within the normal range, the technician can troubleshoot the issue and take the necessary steps to fix it.
Confirming the Power Supply to the Front Oxygen Sensor 2 (LH)
The power supply to the front oxygen sensor 2 (LH) is also vital to diagnosing Subaru Code P0147. The technician should confirm that the power supply is adequate and that the connections are secure. The code will not be resolved if the power supply is insufficient or the connections are loose.
Checking the Sensor
Finally, the technician should inspect the sensor itself. If the sensor is damaged or worn down, it will need to be replaced. A new sensor will ensure the code is resolved and the vehicle is running correctly.
Conclusion
Subaru Code P0147 can be tricky to diagnose, but with the proper knowledge and tools, any technician can diagnose and fix it quickly and efficiently. By understanding the possible causes, scanning the output signal from the ECM, verifying the power supply to the front oxygen sensor 2 (LH), and inspecting the sensor itself, any issue related to the Subaru Code P0147 can be resolved.
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