P0546 code definition
The P0546 code means Exhaust Gas Temperature Sensor (EGT) Circuit High Bank 1 Sensor 1. Alternately, code P0545 may be present, indicating sensor circuit low.
What the P0546 code means
P0546 indicates that there is a malfunction related to the exhaust gas temperature sensor circuit. The purpose of the sensor is to protect the catalytic converter from heat damage. This sensor converts temperature to voltage, and inputs this data to the PCM (powertrain control module). If the voltage sent to the PCM exceeds the predetermined limits set by the vehicle manufacturer, the vehicle will store this code.
What causes the P0546 code?
There are several problems that can cause the sensor to send an excessive voltage signal to the PCM, including:
- Damaged or loose terminals or connectors
- Broken or corroded wires resulting in a short to ground
- A faulty EGT sensor
- An internal or ground short in the EGT sensor
- An aftermarket exhaust system with no EGT provisions
- A major exhaust leak upstream of the EGT sensor
What are the symptoms of the P0546 code?
The symptoms of this code typically only include the stored code itself, as well as a lit Check Engine Light.
How does a mechanic diagnose the P0546 code?
The steps involved in diagnosing this issue include:
Clearing the code(s), then road testing the vehicle and checking for it to come back.
Visually inspecting the exhaust gas temperature sensor and relevant circuitry, focusing in particular on areas that may be in contact with hot components
Inspecting connectors for corrosion or loose connections
Inspecting wires for missing insulation or other damage that could cause a short to ground
Checking the EGT sensor’s resistance using an ohmmeter to ensure it has around 150 ohms
Using a heat gun or hair dryer to heat the sensor while observing the ohmmeter to ensure that the resistance is dropping as the sensor heats up, and rising as it cools down
Testing the voltage on the engine end of the pigtail to ensure that there are five volts at this connector
Common mistakes when diagnosing the P0546 code
The oxygen sensor can sometimes be mistaken for the EGT sensor. The two are different in appearance, however, with the EGT sensor being simply a two-wire plug. It is located between the exhaust manifold and the catalytic converter. Replacing the oxygen sensor will not correct this trouble code. If you’re not confident about your ability to recognize and diagnose the correct sensor, consult a professional.
How serious is the P0546 code?
If not attended to promptly, this code indicates a problem that could lead to catalytic converter damage. While there are temporary fixes that can fool the computer into no longer setting the code, the issue should be addressed as soon as possible.
What repairs can fix the P0546 code?
Repairs that may fix the P0546 code may include:
- Clearing all codes and ensuring that the code returns when the vehicle is road tested
- Visually inspecting theEGT sensor wiring and connectors and replacing if damaged
- Testing the sensor resistance and replacing if below 50 ohms
- In rare cases, replacing the PCM (powertrain control module) or ECM (engine control module)
Additional comments for consideration regarding the P0546 code
Keep in mind that one of the possible causes of this code – installing a catback system in place of the catalytic converter – is against the law in many states due to these systems creating high emissions levels. Before performing such a modification, you should check your state and local laws to make sure that there are no restrictions on such a procedure.
As you inspect the sensor’s connectors for corrosion or loose connections, make sure you go up the pigtail to the connector to make sure that one is secure as well.
Need help with a P0546 code?
YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.