Exhaust Gas Temperature Sensor – Mercedes C-Class W205 – A0009056404

Get your Mercedes-Benz C-class W205 back to reliable DPF regeneration and emission control with this replacement exhaust gas temperature sensor, also referenced in service manuals as the EGT sensor or exhaust temp sensor. Built to OEM specification, matching 0009056404, 0081532228, A0009056404, A0081532228 and 0986259012.

Common signs of failure

A failing EGT sensor on diesel vehicles typically triggers the check engine light with codes P0544, P242F, P0546 or P0549, plus DPF-related warnings on the dashboard. Symptoms include the DPF light staying on, failed or incomplete regeneration cycles, the vehicle entering limp mode after motorway driving, and unusually high exhaust temperatures on diagnostic live data. Left unaddressed, a faulty sensor can lead to DPF damage that costs many times the price of the sensor.

Fitment notes

Direct-fit replacement, no diagnostic coding required. Some installations need a deep socket or EGT-specific spanner to clear the exhaust pipework. Apply anti-seize compound to the threads before fitting and torque to manufacturer spec — exhaust heat-cycling locks fasteners over time.

Frequently asked questions

Where is the EGT sensor located?

Most diesels have multiple EGT sensors monitoring temperature before the turbo, before the DPF, and after the DPF. Identify which position the fault code refers to before ordering.

Will replacing it stop my DPF light?

If the EGT sensor was causing the ECU to misjudge exhaust temperature and abort regeneration, yes. After fitting, drive on the motorway for 20+ minutes to allow a full regeneration cycle.

Can a faulty EGT sensor damage my DPF?

Yes — incorrect temperature readings can cause the ECU to either skip needed regenerations or trigger regen at the wrong time, leading to DPF blockage or melted substrate.