P0402 – Exhaust Gas Recirculation Flow Excessive Detected

Meaning:

When the PCM has detected an excessive amount of EGR, the P0402 happens
The P0402 is triggered when the PCM has detected an excessive amount of EGR

The PCM has detected an excessive amount of EGR.

Main Symptoms:

Most notable symptom is engine surging off idle.

Possible Causes:

  • Defective differential pressure feedback EGR (DPFE) sensor
  • Defective EGR valve
  • EGR valve can’t open because of lack of vacuum
  • Blockage in EGR tube

Diagnostic Steps:

  • Check DPFE sensor voltage to ensure its within specified range
  • If not replace the sensor

Read More: OBD2 Codes List: Meaning, Fixes, and Free Download