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P0548 is a diagnostic trouble code (DTC) for "Exhaust Gas Temperature Sensor Circuit Low Bank 2 Sensor 1 Diagnostic Trouble Code (DTC) P0548". 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 P0548 code occurs when the powertrain control module has sensed some sort of fault in the exhaust gas temperature sensor circuit.
A P0548 is an OBD-II generic code that means there is an issue with the exhaust system gas temperature sensor. The PCM detects voltage changes in the sensor, and interprets the data as exhaust gas temperature. The PCM can then alter the ignition timing or air to fuel ratios in order to decrease the exhaust gas temperature as a way of preserving the catalytic converter. If it detects that variations in the voltage fall outside of the vehicle manufacturer’s suggested levels, the code is created.
The typical reasons for the P0548 code are:
The P0548 code is accompanied by only minimal symptoms that include the service engine warning lighting on the dashboard and the code being stored.
When diagnosing the P0548 code, the technician is going to use the OBD-II scanner, but begins by clearing codes and retesting. They note the freeze frame data and when the issue appears, dealing with any other codes that may be underlying causes. They then do a visual inspection of wires and connections, making sure to repair or replace all loose, corroded, damaged or disconnected components before retesting to see if the code is still appearing.
If so, they look at the exhaust circuitry near the hottest points of the exhaust system and do a check of the sensor’s resistance and voltage. A heat gun is used to heat the sensor and then it may be replaced. The technician may also test the PCM and replace that if needed.
It is not unusual for a technician to mistake oxygen sensors for the exhaust gas temperature sensor, or to believe that both sensors are contained in a single unit. The P0545 code, though is due to the exhaust sensor and simply swapping out the oxygen sensors will not repair the issue.
The P0548 code cannot prevent the car from running, but it can be the result of high temperatures within the exhaust system, and this can lead to the destruction of the catalytic converter or the system circuitry.
The repairs needed to address the P0548 code can include:
The need to replace any control modules is very rare, and yet it could be possible. If all of the diagnostic do not reveal any issues with the exhaust gas temperature sensor, and the electrical circuitry is in working order, a scan of the PCM may be needed to determine if the unit or some part of the CAN Bus is a problem.
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