Skip the auto shop - Our mechanics make house calls

P0547 OBD-II Trouble Code: Exhaust Gas Temperature Sensor Circuit Bank 2 Sensor 1

Check Engine Light

What the P0547 Code Means

P0547 means that the PCM is reading a malfunction in the exhaust gas temperature sensor circuit.

What causes a P0547 code?

The exhaust gas temperature (EGT) sensor is located in the exhaust stream, and sends input voltage readings to the PCM. When system voltage is outside of factory parameters, it will cause a code to be stored, illuminating the malfunction indicator lamp (MIL).

Loose, broken, burned or corroded wiring/terminals/connectors are commonly at fault. Other causes may include an internal short in the sensor, a ground short in the sensor, a failed sensor , a severe exhaust leak from the sensor or an aftermarket exhaust system that lowers exhaust back pressure.

What are the symptoms of a P0547 code?

There may be no drivability symptoms other than an illuminated MIL.

How does a mechanic diagnose a P0547 code?

EGT sensors are used in gasoline engines, diesel engines and turbocharged engines. Exhaust gas temperature sensors are usually a two-wire sensor, situated upstream from the catalytic converter in the exhaust downpipe. In diesel engines, though, the EGT will likely be located in the exhaust system near the diesel particulate filter. Turbocharged engines may locate the EGT sensor near the turbocharger, in the exhaust return/input pipe.

  • EGT sensors are of the temperature-reactive resistor variety, and are supplied with a low-voltage (usually 5 bolts) power wire and a ground wire.

  • As exhaust gas temps pick up, the EGT sensor’s resistance decreases, allowing an increase in the feedback voltage signal the PCM. As the exhaust gas temps decrease, with the engine off and cooling down, circuit resistance increases and feedback voltage to the PCM drops.

  • The PCM reads these variations in voltage as changes in EGT and uses this information to adjust ignition timing and fuel metering to regulate EGT and protect the catalytic converter. A technician will need an OBD-II scanner/code reader and a digital volt/ohmmeter for diagnosis. An infrared thermometer equipped with a laser pointer can also be helpful.

  • Inspect all wiring and connectors, and repair/replace any damaged, disconnected, corroded or shorted wiring, connectors and components as needed. Retest the system to see if repairs were successful. If all wiring, connectors and components (including fuses) seem to be in good working order, connect the scanner/code reader to the diagnostic port. Record any stored codes and freeze frame the data. This information can be useful in diagnosing an intermittent condition.

  • Clear the codes and test drive the vehicle to see if codes return.

  • If codes don’t immediately return, there may be an intermittent condition which may have to be allowed to worsen (or see if it returns) in order to make a proper diagnosis.

  • Visually inspect the EGT sensor and system circuitry. Closely examine any areas where wiring or connectors are close to hot exhaust parts.

  • Repair/replace any damaged, burned or corroded wiring or connectors. If none seem to be present, disconnect and remove the EGT sensor.

  • Using the digital volt/ohmmeter, check the EGT sensor’s resistance. Resistance is usually in the 150 ohm range, but check manufacturer’s specs. Resistance of under 50 ohms is usually cause to replace the sensor.

  • If resistance seems to be within spec, reconnect the leads of the digital volt/ohmmeter and heat the EGT sensor with a heat gun.

  • Watch the digital volt/ohmmeter’s screen to see if the resistance level decreases smoothly as the EGT sensor is heated up.

  • If resistance level stays high while the EGT sensor heats or stays low as it cools, replace the sensor.

  • If everything has checked out to this point, turn the vehicle’s key to the “on” position and check for a voltage reading and ground signal at the EGT sensor’s electrical connections. If there is no low-voltage reading on the signal wire, disconnect the PCM connector and use the digital volt/ohmmeter to perform a continuity test on the wire itself.

  • If the wire checks OK for continuity, the PCM may be faulty. Remember that PCM failure is rare and will require reprogramming if the unit is replaced.

  • If no ground can be found, locate the source and check for continuity. Repair/replace any open or shorted wiring or connectors if needed.

Common mistakes while diagnosing P0547 code

Often the downstream O2 sensor is mistaken for an EGT sensor, or technicians believe that the EGT sensor is part of the heated O2 sensor. Replacement of the O2 sensor will not fix the problem or lead to a successful diagnosis.

How serious is a P0547 code?

A P0547 code may not cause immediate drivability problems, but can mean a failed emissions test.

What repairs can fix a P0547 code?

Addition comments for consideration for P0547 code

High performance aftermarket exhaust systems can result in a P0547 code, due to lowered back pressure (especially when the catalytic converter is left off). In these systems, the problem can be rectified by leaving the EGT sensor disconnected and installing a 2.5 ohm inline resistor between signal and ground wires. The PCM will then read this as sensor resistance and will not register a code.

Need help with a P0547 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.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2159 OBD-II Trouble Code: Vehicle Speed Sensor B Range/Performance
Diagnostic Trouble Code (DTC): P2159 P2159 code definition Vehicle Speed Sensor B Range/Performance...
P2422 OBD-II Trouble Code: Evaporative Emissions Control System (EVAP) Vent Valve Stuck Closed
Diagnostic Trouble Code (DTC): P2422 P2422 code definition Evaporative Emissions Control System (EVAP)...


Related questions

Q: rough idle, heavy missing, fault codes P0301 and P0456. lack of power, where do i start to diagnose this?

Hi there. From the description you have provided, for the P0301 rough idle and heavy misfire and P0456 evaporative small leak detected, the problems are unrelated. The P0301 is a #1 cylinder misfire code. It could be, a spark plug...

Q: Wrench indicator light

The check engine light came on indicating a problem and the vehicle went into limp home mode. Once you turned off the car and turned it back on the problem was not present and the computer resumed normal operation. Thei...

Q: Possible issue with the shift solenoid or TCM?

It could be either one and it's impossible to say without inspecting the car. The difference between the O'Reilly diagnosis and the dealer's is probably one of equipment. O'Reilly uses a generic OBD-II scanner and the dealer should be using...