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P0130 is a diagnostic trouble code (DTC) for "02 Sensor Circuit Malfunction (Bank I Sensor 1)". This can happen for multiple reasons and a mechanic needs to diagnose the specific cause for this code to be triggered in your situation. Our certified mobile mechanics can come to your home or office to perform the Check Engine Light diagnostic. Once we are able to diagnose the problem, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. All our repairs are backed by our 12-month / 12,000-mile warranty.
The P0120 code is associated with the bank 1, sensor 1, oxygen sensor. Your vehicle may have anywhere up to five oxygen sensors.
It also may be related to other codes, such as: P0121, P0122, P0122, P0124. P0125, P0171, or P0175.
P0120 is the OBD-II generic code describing an issue with the bank 1, oxygen sensor 1 (HO2S B1 S1).
It indicates that the engine computer (ECM) is not detecting proper activity from the sensor. This will cause your ECM to turn a light on and change engine management strategies which will affect fuel economy.
The HO2S sensor code may have several causes:
The P0120 code will produce a Check Engine Light on the instrument panel/dash and will likely affect:
P0120 is properly diagnosed with a scan tool capable of sensor readings (not just one from an auto parts store).
A qualified technician can read the data from the scan tool to determine when the problem occurred, or if it is still occurring. They may clear the code / light and test drive the vehicle while monitoring data to see if it returns.
Based upon the conditions of the testing, further diagnosis will be required. Diagnosis could require multiple electrical tools such as:
Just replacing the part never guarantees a success in resolving your problem. It may be caused by several issues as listed above and possibly more.
A visual inspection and tests with a scan tool and special equipment also listed above will verify your problem before potentially spending money and time replacing the sensor.
Waveforms (electrical signals) will have to be evaluated by a scan tool or oscilloscope to ensure the part or repair that is required to be performed. Additional testing may be required.
The P0120 code will not likely cause your vehicle from running, however, it will:
A technician can diagnose the problem with proper tools to verify these potential issues.
The most common potential repairs to address the P0120 code are as follows:
Any sensor issue may occur constantly or intermittently. Some fault codes may require more time to diagnose.
With this particular code, the solution could be simple or require extended time to resolve. Depending on your vehicle, it may take several hours to determine the root cause.
I have experienced this code in the past. After using a scan tool and monitoring the voltage, I could determine if the oxygen sensor was at fault. With the scan tool connected, I typically spray the engine and vacuum lines with brake cleaner while watching the RPM and oxygen sensor values to look for leaks. The RPM or sensor values will change when sprayed if there is a leak in the area sprayed.
I have found vacuum hoses from the engine disconnected, loose air intake hoses from the air filter, and faulty oxygen sensors. In one case I found the wiring was routed incorrectly and caused the wiring to touch the exhaust manifold. The wires burned and shorted to ground causing the fault.
Another case, I found a rodent chewed threw the wiring. The P0120 code may have many root causes which requires a skilled technician to find the cause.
The vacuum hose system requires inspection. A scan tool inspection is required. Then we can determine where the fault lies. We could clear the fault code / light first, and verify if the Check Engine Light returns initially, and go forward from there. It might have been a weird occurrence from bad gas, weather, or a permanent problem.
Vehicles with high mileage (over 100k) may just need a sensor. I typically replace mine at 80,000 miles to prevent problems.
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