P0549Generic code

P0549 Code: Exhaust Gas Temperature Sensor Circuit High (Bank 2)

The P0549 code means the exhaust gas temperature sensor signal (bank 2, sensor 1) is above its maximum value. The main effect is reduced exhaust protection. It usually points to an open circuit or an interrupted ground, and a loose connector is the most common cause.

Severity
Medium
Can I keep driving?
Yes, but with caution
Estimated cost
$60 to $400
Difficulty
Medium
System
Emissions Control
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

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What the P0549 code means

This sensor does the same job as the bank 1 sensor, but on the side opposite cylinder 1 on V engines, or as a second measuring point on some diesels.

The sensor changes its resistance with temperature, and the computer reads the resulting voltage. A high signal, which is what the P0549 code reports, is usually caused by an open circuit or an interrupted ground.

Without the signal, the computer cannot protect that side of the exhaust or control the regeneration properly. The sensor profile pages explain how to test one.

To confirm it, measure the continuity of each wire between the component connector and the computer connector with the key off. It should be under 1 ohm. An infinite reading means the wire is open. If the wiring is good, measure the component itself: an infinite resistance confirms it is open inside.

P0549 code symptoms

  • Check engine light on.
  • Reduced exhaust protection.

Likely causes of the P0549 code

  1. Loose or broken connector. The most frequent cause.
  2. Signal or ground wire cut. The signal rises all the way up to the reference.
  3. Sensor open inside. Its resistance reads infinite.
  4. Short to 5 V or 12 V from rubbing against another wire in the harness.

How to diagnose the P0549 code step by step

  1. Read the sensor value on the scan tool and compare it with what you expect.
  2. Inspect the connector for corrosion, water or loose pins.
  3. Check the supply and ground with the key on: the reference should be correct, with less than 0.1 V of voltage drop on the ground.
  4. Measure the signal with the connector plugged in and watch whether it changes with the condition.
  5. Do a wiggle test on the harness with the scan tool in graph mode.
  6. Check the continuity of each wire to the computer (under 1 ohm).

How to fix the P0549 code

  • Repair the connector or the wiring.
  • Replace the sensor if the tests confirm it is bad.
  • Correct the real condition if there is one.
  • Clear the codes and verify with a road test.

Technical reference data

  • PT200 platinum resistance element or thermocouple.
  • These values are a general guide: check the manufacturer data for your vehicle.

Brand-specific notes

Bank 2 codes show up on V6 and V8 diesels, which have an exhaust sensor on each side of the engine.

P0549 on Ford

Shows up on Ford V6 and V8 diesels.

P0549 on Mercedes

Shows up on Mercedes V6 and V8 diesels.

P0549 on BMW

Shows up on BMW V6 and V8 diesels.

Frequently asked questions about P0549

What does the P0549 code mean?
It is a generic OBD2 code that means the exhaust gas temperature sensor signal on bank 2, sensor 1 is above its maximum value. In practice that points to an open circuit or an interrupted ground.
Can I drive with a P0549 code?
Yes, with some caution. The vehicle drives, but the computer cannot protect that side of the exhaust properly, so get it checked soon.
Do I have to replace the sensor?
Only if the tests confirm it. The connector and the wiring fail just as often.
What does the bank 2 EGT sensor do?
It does the same job as the bank 1 sensor, but on the side opposite cylinder 1 on V engines, or as a second measuring point on some diesels.
How much does it cost to fix P0549?
As a rough guide, between $60 and $400. A connector repair is at the low end, and a new sensor with labor is at the high end.
Will a P0549 code clear itself?
Only if the open was momentary, such as a connector that wiggled back into place. A broken wire or a dead sensor will bring the P0549 code back.
What is the most common cause of P0549?
A loose or broken connector at the sensor. A cut signal or ground wire and a sensor that is open inside are the next most likely causes.

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