Exhaust Gas Temperature Sensor Circuit Low (Bank 2 Sensor 1)
The P0548 code indicates that the exhaust gas temperature (EGT) sensor on Bank 2, Sensor 1 (pre-catalyst) is reporting a voltage lower than the expected range. This sensor monitors exhaust temperature to protect the catalytic converter and DPF. A low voltage reading typically points to a short circuit to ground, faulty sensor, or wiring issues. This can lead to incorrect fuel mixture, reduced engine performance, and potential damage to emission components.
01. Most Common Causes
- Faulty exhaust gas temperature sensor
- Short circuit to ground in sensor wiring
- Corroded or damaged sensor connector
- Open circuit in signal wire
- Engine control module (ECM) issue (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced fuel economy
- Decreased engine performance
- Possible regeneration issues in diesel engines
- Rough idle or hesitation
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm the code and check for additional codes.
Step 2: Visually inspect the EGT sensor and wiring for damage, corrosion, or loose connections.
Step 3: Measure sensor resistance and compare to manufacturer specifications; a short indicates a faulty sensor.
Step 4: Check for voltage at the sensor connector with the ignition on; if no voltage, inspect the circuit for opens or shorts.
Step 5: If all checks pass, replace the EGT sensor and clear the code.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as it can cause poor fuel economy and potential damage to the catalytic converter or DPF. Short trips to a repair shop are acceptable.
How much does it cost to fix?▼
The cost typically ranges from $50 to $150 for parts and labor, depending on the vehicle and sensor location.