Error code

OBD2 P0406

OBD2P0406
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

Exhaust Gas Recirculation Sensor 'A' Circuit High.

Severity

moderateCan drive, but performance and fuel economy may be slightly affected.

Summary

P0406 indicates that the EGR valve position sensor A is reporting an abnormally high signal to the ECM, likely due to a wiring issue or faulty sensor.

Symptoms

  • Malfunction Indicator Light (MIL) illuminated
  • Potential slight drop in performance and fuel economy

Common Causes

  • Faulty EGR position sensor A
  • Wiring issues, such as shorts or poor connections
  • Technical Service Bulletins (TSBs) related to reprogramming the ECM for certain Dodge/Chrysler vehicles

Diagnosis

  1. Check the wire harness for damage or poor connections
  2. Test the EGR position sensor with a multimeter to check resistance values
  3. Disconnect the ECM and EGR position sensor, measure resistance on wires VC, EGLS, and E2

Fixes

  • Replace faulty EGR position sensor A

FAQ

What does P0406 mean?

P0406 indicates a high signal from the EGR valve position sensor A to the ECM.

How do I diagnose P0406?

Diagnose by checking for wiring issues and testing the EGR position sensor with a multimeter.

View source

Not affiliated with OBD2. Answer summarized from the manufacturer's manual linked above; consult that source for the authoritative procedure.

More OBD2 codes

All OBD2 codes →Search more codes →