Error code

OBD2 P0404

OBD2P0404
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

Exhaust Gas Recirculation Control Circuit Range/Performance.

Severity

moderateCan be driven, but performance issues and increased emissions may occur.

Summary

P0404 indicates an issue with the Exhaust Gas Recirculation (EGR) system's control circuit range or performance, affecting how exhaust gases are recirculated back into the engine for more efficient combustion.

Symptoms

  • Check engine light on
  • Engine hesitation
  • Rough idle
  • Engine stalls
  • Increased fuel consumption
  • Exhaust or fuel fumes
  • Smoke coming out of the tailpipe

Common Causes

  • Carbon buildup in EGR system components
  • No vacuum pressure due to defective lines, slices, or tees
  • No power supply to EGR valve
  • Defective EGR valve gasket
  • Defective tubes or hoses
  • EGR valve stuck open or closed

Diagnosis

  1. Inspect vacuum lines, tubes, and hoses for leaks or blockages.
  2. Check if the EGR valve is receiving proper power input (for electrically operated valves).
  3. Verify that exhaust gases have a clear path to be recirculated.
  4. Clean components affected by carbon buildup.

Fixes

  • Replace defective vacuum lines, tubes, or hoses.
  • Repair electrical connections and replace faulty EGR valve if necessary.

FAQ

What does P0404 mean?

P0404 indicates a problem with the Exhaust Gas Recirculation (EGR) system's control circuit range or performance.

How do I fix P0404?

Fixes may include cleaning carbon buildup, replacing defective vacuum lines or hoses, and repairing electrical connections to the EGR valve.

View source

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

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