P0402 Exhaust Gas Recirculation Flow Excessive Detected

P0402 means the EGR monitor detected excessive flow. The system is flowing more exhaust gas than expected or the feedback signal says it is.

Code status

Needs verification

Not yet verified against SAE J2012_202509 / J2012DA. Treat unverified rows as a lookup aid, not repair authority.

System
Emissions
Scope
iso-sae-controlled-p0
Standard
SAE J2012 / ISO 15031-6
Source
legacy-import

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not clean or replace parts randomly; excessive EGR can be a valve, control, feedback, or wiring problem.

Useful checks before replacing parts

Related OBD-II codes

These nearby emissions entries can help compare wording and fault area. They may share the same verification status as the source database.