How is fault code P0412 fixed?

A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training. 1. Read the full code list and freeze frame data. If you've got P0410, P0411 or a flow code sat next to P0412 you're looking at the air pump or plumbing, not just the wiring 2. Get under the car and eyeball the valve, its connector and the loom. Pull the plug and check for green corrosion, damp, or pins that have backed out. This finds the fault on a fair number of cars before you touch a meter 3. Back-probe the connector with a multimeter and have someone fire it up cold. You should see the ECU command the valve briefly in the first 30 to 90 seconds. No command means look upstream at fuse, relay and ECU 4. With the plug off, measure the resistance across the valve solenoid and compare to the workshop figure, typically a low number in the single-digit to low tens of ohms. Open circuit or way out of spec condemns the valve 5. Check the feed and ground are actually getting to the connector when commanded. A good earth is the thing people skip, and it causes plenty of these 6. Fix what you fo

Secondary Air Injection System Switching Valve A Circuit Malfunction

Jump to the fix

Severity

Low

Can I keep driving?

Usually drivable; have it fixed at the first opportunity.

First step

A typical diagnostic sequence used by mechanics, provided here for educational reference only. Diagnostic work should be performed by a qualified mechanic with the appropriate tools and training. 1. Read the full code list and freeze frame data. If you've got P0410, P0411 or a flow code sat next to P0412 you're looking at the air pump or plumbing, not just the wiring 2. Get under the car and eyeball the valve, its connector and the loom.

PPowertrain
0Generic code
4Emissions
12Sequence number

What does it mean?

P0412 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Secondary Air Injection System Control A Circuit . This is a standardised OBD-II code. The technical definition is the same regardless of the make or model of vehicle, although specific causes and symptoms can vary between vehicles.

Symptoms

Likely causes

How to fix it

Codes From the Same System

All Fault Codes

Related Similar Codes

This information follows the generic OBD-II definition and does not replace a vehicle-specific diagnosis. The severity rating is rule-based; an authorised diagnostic reading is required for a definitive answer.