Emissions

P2493 — EGR Temperature Sensor Correlation Fault

Severity: medium Drive with care, to a shop

What P2493 means

The engine control unit compares readings from the EGR temperature sensors, typically before and after the EGR cooler, against what it expects for the current exhaust gas flow. When the difference doesn't make sense, it sets P2493. This usually points to restricted or incorrect EGR flow or poor cooling, though a faulty sensor can cause it too.

Symptoms

  • Check engine light on
  • Rough idle
  • Smoke under acceleration
  • Reduced engine power
  • Hesitation when accelerating
  • Possible limp mode

Possible causes

  1. Clogged or carbon-fouled EGR cooler
  2. Sticking or slow EGR valve
  3. Failed EGR temperature sensor
  4. Carbon buildup in EGR passages
  5. EGR actuator or position sensor fault
  6. Wiring or connector damage or corrosion
  7. Vacuum supply fault on vacuum-operated valves

How to diagnose

  1. Read all codes and freeze frame data, noting any other EGR, boost or airflow codes
  2. Check battery voltage and sensor supply voltage
  3. Inspect wiring and connectors at the EGR temperature sensors and valve
  4. Compare both temperature sensor readings on a cold engine; they should be close
  5. Compare commanded and actual EGR valve position in live data
  6. Remove the valve and look for carbon, sticking or binding
  7. Check the cooler and passages for blockage and for signs of coolant leaks
  8. On vacuum-operated systems, test hoses, solenoid and vacuum level

Common fixes

  • Clean or replace the EGR valve
  • Clean or replace the EGR cooler and passages
  • Replace the faulty EGR temperature sensor
  • Repair wiring and connectors
  • Replace the EGR actuator or position sensor
  • Fix vacuum line leaks

Questions and answers

What does P2493 mean?

The ECU found that the EGR temperature sensor readings don't agree with each other or with its model. The cause can be a bad sensor, or a clogged valve or cooler.

Can I drive with P2493?

For a short time, yes, but don't put off the repair. Carbon buildup and a failing cooler get worse and can lead to costlier damage.

Will cleaning the EGR valve fix it?

Often, if carbon is the cause. Check the sensors, wiring and cooler first, or the code may come back.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.