Function of the EGT Sensor‌

The Exhaust Gas Temperature (EGT) sensor monitors the temperature of exhaust gases in a vehicle's exhaust system. Key functions include:

Engine Protection‌: Prevents overheating by alerting the Engine Control Unit (ECU) to adjust fuel injection, ignition timing, or airflow, reducing combustion temperatures.
Emissions Control‌:
In diesel engines, aids Diesel Particulate Filter (DPF) regeneration by ensuring optimal temperatures for burning trapped soot.
In gasoline engines, helps protect catalytic converters from thermal damage.
Diagnostic Alerts‌: Triggers the "Check Engine" light and stores fault codes (e.g., P0544, P2463) if temperatures exceed safe limits.
Symptoms of a Faulty EGT Sensor‌
Illuminated "Check Engine" light.
Reduced engine performance or limp mode.
Poor fuel efficiency.
Failed emissions tests or DPF regeneration issues.
Diagnostic Steps‌
Scan for Codes‌: Use an OBD-II scanner to retrieve fault codes.
Visual Inspection‌: Check for damaged wiring, corrosion, or sensor physical damage.
Resistance/Voltage Test‌: Compare sensor readings (cold vs. heated) to manufacturer specifications using a multimeter.
Replacement Procedure‌

Safety Precautions‌:

Allow the exhaust system to cool completely.
Disconnect the negative battery terminal.

Sensor Removal‌:

Locate the sensor (typically near the exhaust manifold, turbocharger, or DPF).
Disconnect the electrical connector.
Use a penetrating oil (e.g., WD-40) on stuck sensors. Remove with a wrench or socket.

Installation‌:

Apply anti-seize compound to the new sensor’s threads (if not pre-coated).
Install the sensor and tighten to the specified torque (refer to service manual).
Reconnect the electrical connector and battery.

Post-Replacement Steps‌:

Clear fault codes with a diagnostic tool.
Test-drive the vehicle to verify normal operation and monitor live EGT data.
Critical Notes‌
Torque Specifications‌: Over-tightening can damage the sensor or exhaust components.
Exhaust Leaks‌: Ensure no leaks after installation, as they can skew sensor readings.
ECU Reprogramming‌: Some models may require ECU updates for sensor calibration.
Professional Help‌: Complex placements (e.g., turbo-adjacent sensors) may necessitate specialist tools or expertise.

Always consult the vehicle’s service manual or a certified technician for model-specific guidance. Proper maintenance ensures compliance with emissions standards and prevents costly engine damage.