Code P0549 – Exhaust Gas Temperature (EGT) Sensor – High Circuit (Bank 2)
1. Meaning of Code P0549
The P0549 code indicates a problem with the exhaust gas temperature (EGT) sensor located in the exhaust manifold or upstream of the catalytic converter. This sensor monitors the exhaust gas temperature and helps the engine control unit (ECU/PCM) adjust performance to prevent overheating.
This code is specific to bank 2, which is the side of the engine that does not contain cylinder number 1.
2. Symptoms of Code P0549
🔍 Generally, symptoms are limited, but here’s what can happen:
✅ Check Engine Light illuminated
✅ Possible limp mode activation (especially on diesel engines)
✅ Reduced engine performance or increased fuel consumption
✅ Poor diesel particulate filter (DPF) operation on diesel vehicles
3. Possible Causes of Code P0549
🔧 Here are the main reasons that can trigger this error code:
✔️ Loose or corroded connectors of the EGT sensor
✔️ Broken, damaged, or short-circuited wires
✔️ Faulty EGT sensor (wear or internal failure)
✔️ Replacement of the exhaust system without EGT sensor support
✔️ Problem with the engine control module (ECU/PCM) (rare)
4. How to Fix Code P0549?
🔍 Step 1: Locate and Inspect the EGT Sensor
📌 The EGT sensor is located upstream of the catalyst or, on diesel engines, before the particulate filter (DPF).
✔️ Locate it and check the condition of the wiring harness and connectors.
✔️ Clean corroded terminals with electrical contact spray.
🔍 Step 2: Check the Wiring Condition
🔧 Follow the sensor harness to its connector.
✔️ Look for cut, burned, or poorly insulated wires.
✔️ Check for a short circuit to ground.
🔍 Step 3: Test the EGT Sensor with a Multimeter
🛠️ Resistance test (with a multimeter in ohmmeter mode):
✔️ Disconnect the sensor and measure the resistance between the terminals.
✔️ A typical value is around 150 ohms.
✔️ If the resistance is very low (< 50 ohms) or infinite, the sensor is faulty.
🔥 Heating test:
✔️ Heat the sensor with a hairdryer or heat gun.
✔️ The resistance should decrease as the temperature increases and rise again when cooling.
✔️ If the value remains constant, replace the sensor.
🔍 Step 4: Check the Sensor Power Supply
📌 Turn on the ignition and measure the voltage at the sensor connector on the engine side.
✔️ You should get about 5V.
✔️ If no voltage is present, there may be a problem with the wiring harness or PCM.
🔍 Step 5: Replace the EGT Sensor if Necessary
🔧 If the sensor is outside normal values, it must be replaced.
✔️ Use a special sensor wrench to remove it.
✔️ Apply penetrating lubricant to avoid damaging the threads.
✔️ Reconnect the connector properly and clear the error code.
5. Temporary Solution (if EGT Sensor Removal)
⚠️ Warning: This solution is a temporary trick and may be illegal depending on your region.
If your catalytic converter has been removed, you can trick the computer by replacing the sensor with a 2.2 ohm resistor.
✔️ Disconnect the sensor and insert the resistor into the harness connector.
✔️ Insulate with tape.
✔️ This will make the PCM believe the sensor is working.
⚠️ Note: This method does not always work and may prevent diesel particulate filter (DPF) regeneration.
6. Common Mistakes to Avoid
🚨 Do not immediately replace the sensor without testing:
✔️ The wiring harness and connectors (often the cause)
✔️ The 5V sensor power supply
✔️ The EGT sensor resistance
7. Conclusion
The P0549 code indicates a problem with the exhaust gas temperature sensor. It can be caused by a faulty sensor, wiring issue, or modified exhaust.
🔧 Recommended solution:
✅ Check connectors and wiring harness
✅ Test resistance and power supply
✅ Replace the sensor if necessary
🚗 If the problem persists, consult a professional for an in-depth diagnosis.