P0549
Exhaust Gas Temperature Sensor Circuit High - Bank 2 Sensor 1
Powertrain Emission Controls EGT Sensor Circuit 🟡 Moderate — Fix within a week
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What This Actually Means
In plain language — no jargon

The exhaust temperature sensor on Bank 2 is sending a voltage signal that's too high, like a thermometer reading impossibly hot. The engine computer thinks the exhaust is overheating when it may actually be fine or the sensor itself is faulty.

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Symptoms You May Notice
3 known symptoms for this code
Check Engine Light illuminated
Reduced engine power or limp mode activation
Rough idle or hesitation during acceleration
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Embedded Systems Insight
What the ECU/ECM is actually computing

The ECU monitors the EGT sensor voltage to ensure exhaust temperatures stay within safe operating range. When voltage exceeds the maximum threshold, the ECU sets a fault code. The sensor operates on a linear voltage scale where higher voltage indicates higher temperature.

Voltage & Parameter Thresholds

Parameter Normal Range Fault Condition
EGT Sensor Voltage (Bank 2 Sensor 1) 0.5–4.5 volts (temperature-dependent) >4.8 volts or open circuit detected
Exhaust Gas Temperature 200–900°C under normal operation >950°C or sensor signal implausible
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Diagnostic & DIY Fix Guide
Check these in order — from cheapest to most complex
1
Wiring harness and connectors
Inspect and clean the EGT sensor connector and wiring for corrosion, loose pins, or damaged insulation.
2
EGT Sensor (Bank 2, Sensor 1)
Replace the exhaust gas temperature sensor if connector and wiring are clean; sensor failure is the most common cause.
3
ECU software or reprogram
Update engine control module firmware if available, as software glitches can occasionally cause false high readings.