P0405 – Exhaust Gas Recirculation Sensor A Circuit Low

Meaning:

When the EGR valve pintle is not moving as it should, the P0405 happens
The P0405 is triggered when the EGR valve pintle is not moving as it should

The EGR valve pintle is not moving as it should either because of unusually low voltage or its position is lower than the PCM has commanded.

Main Symptoms:

Check Engine Light comes on.

Possible Causes:

  • Open or short in reference or ground circuit
  • Defective EGR valve
  • Defective PCM (least likely)

Diagnostic Steps:

  • Visually inspect all wiring to EGR to ensure there are no shorts or opens
  • Using a bidirectional scanner, open and close EGR valve and watch how it responds. If its moving properly then it’s an intermittent problem

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