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P0549 – Exhaust Gas Temperature Sensor Circuit High - Bank 2 Sensor 1 (OBD2)

P0549 means "Exhaust Gas Temperature Sensor Circuit High - Bank 2 Sensor 1". The voltage in the exhaust gas temperature (EGT) sensor circuit is above the permitted maximum. For most sensors this points to an open signal or ground wire – the signal "floats" up to the reference voltage – or to a short to voltage.

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P0549 quick summary

Fault codeP0549
MeaningExhaust Gas Temperature Sensor Circuit High - Bank 2 Sensor 1
SystemPowertrain (Engine & Transmission)
VehiclesGeneric OBD2
SeverityMedium
Can I drive?Yes, gently. On diesels DPF regeneration may stop, so have it fixed before the filter clogs.
Repair cost€40 – €300

How exhaust gas temperature sensors work

Exhaust gas temperature sensors measure the exhaust temperature at several points to protect the turbocharger and catalytic converter and to control DPF regeneration.

EGT sensors are thermistor or thermocouple-type sensors screwed into the exhaust – typically before the turbocharger, before the oxidation catalyst and before or after the DPF on diesels. They measure temperatures from below zero up to around 900–1,000 °C.

The control unit uses the readings to protect components from overheating (it reduces power when temperatures get too high) and to control DPF regeneration, which needs exhaust temperatures around 600 °C. Codes P0544–P0549 report circuit faults for sensor 1 of bank 1 and bank 2.

Sensors fail from heat cycling, their cables are damaged by heat and vibration, and connectors corrode. A faulty EGT sensor on a diesel often stops DPF regeneration, which can lead to DPF blockage codes.

Bank 2 is the cylinder row that does NOT contain cylinder 1, so this code only appears on V6, V8, V10, V12 and boxer engines.

Symptoms of P0549

  • Check Engine light on
  • DPF regeneration not completing, DPF warning
  • Reduced power or limp mode
  • Implausible temperature readings in live data
  • Often no driving symptoms

Most common causes of P0549 (most likely first)

Mechanic's Pro Tip

EGT sensors are often seized in the exhaust. Apply penetrating oil and loosen them with the exhaust warm (not hot) – a snapped sensor thread turns a cheap job into an expensive one.

  1. 1.Open circuit in the signal or ground wire

    Most likely

    A loose ground connection is a very common cause.

  2. 2.Signal wire shorted to the 5 V reference or battery voltage

  3. 3.Faulty exhaust gas temperature (EGT) sensor

  4. 4.Damaged sensor cable

    Melted or broken near hot exhaust parts.

  5. 5.Corroded connector

  6. 6.Wiring fault to the control unit

  7. 7.Exhaust leak near the sensor

Step-by-step diagnostic guide

  1. 1

    Read codes and compare temperatures

    Read all codes. On a cold engine all EGT sensors should show roughly the outside temperature.

  2. 2

    Check signal and ground

    With the ignition on and the exhaust gas temperature (EGT) sensor plugged in, back-probe the signal and ground wires. A signal stuck at reference or battery voltage points to an open ground/signal wire or a short to voltage.

    Multimeter: Ground wire to battery negative: below about 0.1 V. Signal stuck at about 5 V (or 12 V) = open or short to voltage.

  3. 3

    Check the cable and connector

    Inspect the sensor cable along its length for heat damage and the connector for corrosion.

  4. 4

    Measure the sensor

    Measure the resistance and compare with the specification.

    Multimeter: Many PTC/NTC EGT sensors read roughly 200–250 Ω at room temperature (PT200 type); check the type for your sensor.

  5. 5

    Check wiring

    Check the wiring to the control unit for opens and shorts.

  6. 6

    Replace and verify

    Replace the sensor using anti-seize on the thread, clear codes and check that DPF regeneration completes.

Frequently asked questions

Can I keep driving with P0549?

Yes, gently. On diesels DPF regeneration may stop, so have it fixed before the filter clogs.

How much does it cost to fix P0549?

Typical repair costs are 40 € – 300 €, depending on the cause and the vehicle. The most common fixes are: open circuit in the signal or ground wire; signal wire shorted to the 5 V reference or battery voltage; faulty exhaust gas temperature (EGT) sensor. Always confirm the cause with the tests above before buying parts.

Can a bad EGT sensor block the DPF?

Indirectly yes. Without a reliable temperature signal the control unit may not start or finish regenerations, so soot builds up.

How many EGT sensors does a car have?

Petrol engines may have one or none; modern diesels often have two to four.

What is the difference between P0549 and similar codes?

P0549 belongs to a group of codes for the same component that differ in the type or location of the fault: P0544 – Exhaust Gas Temperature Sensor Circuit - Bank 1 Sensor 1; P0545 – Exhaust Gas Temperature Sensor Circuit Low - Bank 1 Sensor 1; P0546 – Exhaust Gas Temperature Sensor Circuit High - Bank 1 Sensor 1; P0547 – Exhaust Gas Temperature Sensor Circuit - Bank 2 Sensor 1; P0548 – Exhaust Gas Temperature Sensor Circuit Low - Bank 2 Sensor 1. The tests on this page apply to the whole group; the type of fault tells you where to start.

Related fault codes

This guide is for information only. Working on vehicles can be dangerous — if you are unsure, have the car checked by a qualified mechanic. Values can differ between model years; always check the manufacturer's repair information.