P0545
Exhaust Gas Temperature Sensor Circuit Low - Bank 2 Sensor 1
Powertrain Emission Controls Exhaust Diagnostics 🟡 Moderate — Fix within a week
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What This Actually Means
In plain language — no jargon

Your exhaust temperature sensor on bank 2 is reading too low, like a faulty thermometer showing colder than actual. The engine computer can't properly monitor exhaust heat, affecting emissions control.

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Symptoms You May Notice
3 known symptoms for this code
Check Engine Light illuminated
Reduced engine performance or limp mode
Increased exhaust emissions
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Embedded Systems Insight
What the ECU/ECM is actually computing

The ECU monitors voltage from the exhaust gas temperature (EGT) sensor to verify post-catalyst exhaust temperatures. A low signal voltage indicates either a faulty sensor, wiring break, or short circuit. The ECM compares sensor output against expected thermal profiles based on engine load and fuel injection.

Voltage & Parameter Thresholds

Parameter Normal Range Fault Condition
EGT Sensor Voltage 0.5V–4.5V (proportional to 200–900°C exhaust temp) Below 0.1V continuously or erratic
Signal Circuit Resistance Sensor coil: 10–100 ohms at operating temp Open circuit (infinite) or short to ground
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Diagnostic & DIY Fix Guide
Check these in order — from cheapest to most complex
1
Wiring harness connector
Inspect and clean the sensor connector for corrosion, oxidation, or loose pins.
2
Exhaust Gas Temperature Sensor Bank 2 Sensor 1
Replace the sensor if voltage remains low after connector service and wiring test.
3
Sensor wiring harness
Check for damaged insulation, pinches, or disconnects in the circuit between sensor and ECU.