Error code

OBD2 P0402

OBD2P0402
Diagnostic Trouble Code· Standard OBD-II fault code read from the vehicle's onboard diagnostics.

What it means

Exhaust Gas Recirculation Flow Excessive Detected.

Severity

moderateCan drive, but performance issues may occur.

Summary

P0402 indicates excessive exhaust gas recirculation flow detected in the EGR system.

Symptoms

  • Engine misfires
  • Poor acceleration
  • Increased fuel consumption

Common Causes

  • Carbon buildup or blockage at the EGR valve connection to the intake manifold
  • Vacuum line leaks in the EGR system
  • Faulty EGR solenoid not opening or closing properly

Diagnosis

  1. Perform an EGR idle test to check for blockages.
  2. Test the vacuum lines and solenoid for leaks or improper operation.
  3. Check electrical connections and signals from the PCM to the EGR valve and solenoid.

Fixes

  • Clean or replace the EGR valve if it is blocked by carbon buildup.
  • Repair or replace vacuum lines and check for leaks in the system.

FAQ

What causes P0402?

Common causes include carbon buildup at the EGR valve, vacuum line leaks, and a faulty EGR solenoid.

How do I test for P0402?

Perform an idle test to check for blockages, inspect vacuum lines for leaks, and verify electrical signals from the PCM.

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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