Exhaust Gas Temperature Sensor Circuit Low (Bank 1 Sensor 1)
The P0545 code indicates that the exhaust gas temperature (EGT) sensor on Bank 1, Sensor 1 (pre-catalyst) is reporting a voltage lower than the expected range. This sensor monitors exhaust temperature to protect the catalytic converter and optimize engine performance. A low circuit condition typically means the sensor signal is shorted to ground, has internal failure, or the wiring is damaged. This can lead to incorrect fuel trims and potential catalyst damage if ignored.
01. Most Common Causes
- Faulty exhaust gas temperature sensor
- Short to ground in sensor wiring or connector
- Corroded or damaged sensor connector
- Engine control module (ECM) issue (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced fuel economy
- Possible limp mode or reduced engine power
- Excessive exhaust smoke or odor
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm P0545 and check for other codes.
Step 2: Visually inspect the EGT sensor and wiring for damage, corrosion, or loose connections.
Step 3: Disconnect the sensor and measure resistance; compare to manufacturer specs (typically 100-200 kΩ at cold).
Step 4: Check for short to ground by measuring voltage between signal wire and ground with key on (should be ~5V reference).
Step 5: If wiring and sensor check out, test the ECM output or replace the sensor.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances. The low circuit can cause incorrect fuel mixture, potentially damaging the catalytic converter or engine. You may experience reduced performance and fuel economy.
How much does it cost to fix?▼
The typical repair cost ranges from $50 to $150 for parts and labor. The sensor itself costs $30-$80, and labor is about $20-$70 depending on accessibility.