OBD-II · Engine and powertrain (P)
P0548
Exhaust gas temperature sensor circuit low, bank 2 sensor 1
What it means
The signal is below the valid range, most often a short to ground or a failed sensor. Exhaust gas temperature (EGT) sensors protect the turbo and catalysts and let the engine computer control DPF regeneration. Which physical sensor is "sensor 1" depends on the car; identify bank 2 from the engine-specific service information.
Symptoms
- engine warning light
- DPF regeneration may be blocked, leading later to a DPF warning
- possibly reduced power (limp mode)
- car may otherwise drive normally
Likely causes, most likely first
| No. | Cause |
|---|---|
| 01 | wiring shorted to ground |
| 02 | failed EGT sensor |
| 03 | water or corrosion in the connector |
| 04 | chafed wiring near the exhaust |
What to check, step by step
- 01With the engine cold, read all EGT sensors in live data - they should all be close to outside temperature.
- 02Inspect the sensor connector and wiring near the turbo and exhaust for melting, chafing and corrosion.
- 03With the circuit isolated as specified, compare resistance with the specification for that exact sensor at the measured temperature. Compare other sensors only if they have the same electrical characteristics.
- 04Check wiring continuity back to the engine computer.
- 05Replace the sensor if faulty; they often seize, so use penetrating oil and remove with the exhaust warm.