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P0142 is a diagnostic trouble code (DTC) for "O2 Sensor Circuit Malfunction (Bank 1, Sensor 3)". 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.
O2 Sensor Circuit Malfunction (Bank 1, Sensor 3)
P0142 is the OBD-II generic code indicating the Engine Control Module (ECM) input from the O2 sensor circuit for bank 1 sensor 3 is not within specifications.
The O2 sensor bank 1 sensor 3 is downstream of the last catalyst in the exhaust system; an exhaust leak before the sensor can cause the code from excessive oxygen getting into the exhaust stream.
The ECM detects a short or open circuit in the O2 bank 1 sensor 3 circuit.
The ECM does not use the input from this O2 sensor for controlling the engine fuel control, so this code should not account for any abnormal drive complaints.
The Check Engine Light will be illuminated, indicating a problem with the downstream catalyst O2 sensor 3 for bank 1.
Checks electrical connections to the O2 bank 1 sensor 3
Checks the exhaust system before the O2 sensor for any exhaust leaks
Scans to see if codes P0143 and P0144 are present, or if the problem is intermittent, and can be ignored unless the problem returns
Follows the manufacturer's specific pinpoint tests for further diagnosis
Follow these simple guidelines to prevent misdiagnosis of code:
Scan for codes P0143 and P0144, and repair these codes first to complete the diagnosis.
Check for any exhaust leaks or damages to the exhaust before the O2 sensor that could cause the sensor to not work properly.
The code is for the sensor behind the last catalyst on bank 1 of the exhaust and may contribute to an excessive exhaust emission if the problem is the catalyst.
The code will not cause the engine to run any different in most circumstances.
The vehicle will fail emission testing, since the Check Engine Light is on.
The exhaust may have a leak and cause fumes to get into the passenger compartment.
Checking and repairing exhaust leaks before the catalyst
Repairing or replacing the wiring or connection to the O2 sensor for bank 1 sensor 3
The code P0142 will not cause a driveability problem since the code is in relation to the last catalyst in the exhaust performance; it is for cleaning the exhaust stream only, not for engine fuel control.
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