P0402 Code: EGR Flow Excessive Detected
CodePage.genericDisclaimer
Qu'est-ce que cela signifie ?
Code P0402 indicates a problem with the Exhaust Gas Recirculation (EGR) system. The EGR system reduces NOx emissions by recirculating a portion of exhaust gas into the intake manifold.
Diagnostic system: General powertrain circuit
On a Audi A4, the P0402 code should be diagnosed as part of the general powertrain circuit group. Related codes and live data from this same system can change the repair priority, so avoid replacing parts from the code name alone.
Most Common Causes for Audi A4
- Vanne EGR bloquée ou défectueuse
- Passages EGR obstrués
- Faisceau de câblage endommagé ou cassé
- Fuite de vide dans le système d'admission
- Connecteur électrique corrodé ou desserré
Symptômes à surveiller
- Le voyant moteur est allumé
- Ralenti irrégulier ou instable
- Cliquetis ou détonation du moteur
- Échec au contrôle des émissions
- Le moteur cale de façon inattendue
- Perte significative de puissance du moteur
CodePage.beforeReplacing
- Record freeze-frame data and related codes before clearing the fault.
- Inspect wiring, connectors, vacuum lines, fluid leaks, and fuses tied to the named system.
- Use live data or a multimeter to confirm the failed circuit before replacing parts.
- Check for blown fuses, weak battery voltage, and damaged connectors before buying major parts.
Comment Diagnostiquer
CodePage.commonMistakes
Treating the code description as a parts list instead of verifying the circuit, operating conditions, and related codes. Always confirm the fault with freeze-frame data, live data, visual inspection, and circuit checks before spending money on parts.
CodePage.faq
Can I drive with the P0402 code?
If the check engine light is solid, you can usually drive to a safe location or mechanic. If the light is flashing, pull over immediately to prevent catastrophic engine or catalytic converter damage.
Will the P0402 code clear itself?
Once the underlying problem is fixed, the engine computer will run its self-checks. If it passes over several drive cycles, the light will turn off automatically. You can also clear it immediately using an OBD2 scanner.
Will this code fail an emissions test?
Yes. If the Check Engine Light is on due to the P0402 code, your Audi will automatically fail an OBD2 plug-in emissions or smog test.
What should I check first for P0402?
Record freeze-frame data and related codes before clearing the fault. Inspect wiring, connectors, vacuum lines, fluid leaks, and fuses tied to the named system. Use live data or a multimeter to confirm the failed circuit before replacing parts.
Join the Discussion
Estimation de réparation
Fuse, connector, wiring, cleaning, or basic inspection
Major component replacement after live data and circuit tests confirm failure
Comprend les pièces et la main-d'œuvre. Peut varier selon l'emplacement.
Costs vary widely; start with visual inspection and circuit confirmation to avoid unnecessary parts.
Difficulté de réparation (DIY)
Can usually be performed at home with basic hand tools.