When it comes to Subaru cars, one of the most common issues is the code P0140. This code is triggered when the output voltage of the rear O2 sensor meets one of the following conditions for longer than 0.2 seconds: minimum output voltage is greater than 0.15 V, or maximum output voltage is less than 0.55 V. This code can be caused by a variety of issues, including water in the rear oxygen sensor connector, wiring harness between ECM and rear oxygen sensor connector needs repair, loose or damaged exhaust system parts, and defective rear oxygen sensor. To help you better understand the causes and solutions of the Subaru code P0140, we have put together a table of the most common causes and solutions.
Causes and Solutions of Subaru Code P0140
| Causes | Solutions |
|---|---|
| Water in the rear oxygen sensor connector or coupling connector | Replace the connector or coupling connector, depending on the source of the water. |
| Wiring harness between ECM and rear oxygen sensor connector needs repair | Repair the wiring harness between the ECM and the connector. |
| Loose or damaged exhaust system parts | Inspect the exhaust system and replace any loose or damaged parts. |
| Defective rear oxygen sensor | Replace the defective rear oxygen sensor. |
Water in the Rear Oxygen Sensor Connector or Coupling Connector
The most common cause of Subaru code P0140 is water in the rear oxygen sensor connector or coupling connector. To resolve this issue, you will need to replace the connector or coupling connector, depending on the source of the water. It’s important to repair the issue quickly, as water can cause corrosion and damage other parts of the vehicle.
Wiring Harness between ECM and Rear Oxygen Sensor Connector Needs Repair
Another potential cause of Subaru code P0140 is a faulty wiring harness between the ECM and the connector. If this is the case, you will need to repair the wiring harness to resolve the issue. This can be a difficult and time-consuming process, so it’s best to leave this repair to an experienced mechanic or technician.
Loose or Damaged Exhaust System Parts
If the wiring harness is in good condition, the issue may be due to a loose or damaged part of the exhaust system. To determine the source of the problem, it’s necessary to inspect the exhaust system and replace any loose or damaged parts.
Defective Rear Oxygen Sensor
If all other causes have been ruled out, the issue may be due to a defective rear oxygen sensor. In this case, the best solution is to replace the defective sensor. This is a relatively easy and inexpensive repair, but it should still be performed by a qualified mechanic or technician.
Conclusion
In conclusion, the Subaru code P0140 can be caused by a variety of issues, including water in the rear oxygen sensor connector, wiring harness between ECM and rear oxygen sensor connector needs repair, loose or damaged exhaust system parts, and defective rear oxygen sensor. To ensure that the issue is resolved quickly and correctly, it is best to have it inspected and repaired by an experienced mechanic or technician. By taking the steps necessary to fix Subaru code P0140, drivers can ensure that their vehicle is running safely and efficiently.
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