What Does P0549 Mean?
The ECM has detected that the exhaust gas temperature sensor circuit on Bank 2, Sensor 1 is reading above the expected voltage or resistance threshold. This high-input condition typically indicates an open circuit in the Bank 2 EGT sensor wiring, a disconnected sensor, or a failed sensor with abnormally high or infinite resistance. The ECM loses the ability to accurately monitor Bank 2 pre-catalyst exhaust temperatures.
Common Causes
35%
Open circuit in the Bank 2 EGT sensor wiring caused by a broken wire from vibration fatigue or heat deterioration
30%
Failed Bank 2 EGT sensor with open internal thermistor element from thermal shock
25%
Disconnected or improperly seated Bank 2 EGT sensor connector with backed-out pins
10%
Signal wire shorted to a voltage source due to harness damage contacting a powered circuit
Diagnostic Steps
1
Step 1: Verify the Bank 2 EGT sensor connector is fully engaged and not disconnected. Check the locking tab and terminal seating. A disconnected sensor is the most common simple fix.
2
Step 2: Disconnect the sensor and measure element resistance. An open-loop reading (OL/infinity) confirms a failed sensor. A valid reading at room temperature should be 100-200 ohms.
3
Step 3: Substitute a known resistance (100-150 ohm resistor) at the ECM-side connector to verify the ECM reads a plausible temperature. If the reading is correct, the harness is intact and the sensor is faulty.
4
Step 4: If the reading remains high with a test resistor, perform continuity checks on both wires from the sensor connector to the ECM. Focus on areas with high vibration and heat exposure.
5
Step 5: Check for battery voltage on the signal lines (should not be present). Repair any open circuits or shorts. Replace the EGT sensor if defective. Clear codes and verify Bank 2 EGT tracks with Bank 1 during warm-up.
Estimated Repair Cost
$70 - $300
Parts + labor, varies by vehicle and location
The ECM has detected that the exhaust gas temperature sensor circuit on Bank 2, Sensor 1 is reading above the expected voltage or resistance threshold. This high-input condition typically indicates an open circuit in the Bank 2 EGT sensor wiring, a disconnected sensor, or a failed sensor with abnorm...
The most common cause of P0549 (Exhaust Gas Temperature Sensor Circuit High (Bank 2 Sensor 1)) is: Open circuit in the Bank 2 EGT sensor wiring caused by a broken wire from vibration fatigue or heat deterioration
Typical repair costs for P0549 range from $70 to $300, depending on the vehicle, location, and whether you do it yourself or go to a shop.
A false high EGT reading may cause unnecessary power reduction or limp mode, significantly affecting drivability. The ECM may also apply unneeded protective fuel enrichment, increasing fuel consumption and emissions.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0549 to identify the root cause.
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Quick Info
Category
Powertrain
System
Exhaust / Emission Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
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