# P0412 — Generic Powertrain — Auxiliary Emission Controls

> ClearTheCode diagnostic code reference (not OEM service data).

Source: https://clearthecode.com/codes/P0412

**System:** Powertrain · Auxiliary Emission Controls

**Severity:** moderate

## Description

Auxiliary emission system fault (EGR, EVAP, catalyst, secondary air). Inspect the specific subsystem identified by the code.

## Diagnostic snapshot

- **Difficulty:** 6/10 — Intermediate diagnostics
- **Est. repair cost:** $120 – $450

## Diagnostic workflow

1. Confirm P0412 with a live scan — note pending vs stored and freeze frame data.
2. Inspect wiring/connectors and related sensors before replacing modules.
3. Clear codes and road-test; re-scan after two drive cycles if the monitor must set.