P0412

Secondary Air Injection System Switching Valve "A" Circuit

Car Fault Codes Emissions & exhaust

Can you still drive? Yes, normally

Who can fix it? Needs a workshop

Typical repair time 30 minutes – 2.5 hours

Typical cost SAR 100 to 1,500

What it means

The engine computer has detected an electrical fault, such as an open or short, in the circuit of the switching valve or its control solenoid in the secondary air system. This valve opens the air path to the exhaust at cold start, and a fault stops the system from working, raising emissions.

Symptoms4

Check engine light on.
Usually no driving symptoms.
Failed emissions test.
A flow code such as P0411 may appear with it.

Possible causes5

Corroded or loose connector at the switching valve or its solenoid.
Open or shorted wiring in the circuit.
Failed internal valve coil.
Blown fuse feeding the circuit on some vehicles.
Faulty driver circuit inside the engine computer (rare).

How to diagnose5

Visually inspect the connector and wiring for corrosion or damage.
Check for voltage at the connector with the ignition on.
Measure the valve coil resistance and compare it with the manufacturer specification.
Check the control wire to the computer for continuity and shorts.
Command the valve with a scan tool and listen for it to operate.

How to fix5

Clean or repair the connector.
Repair open or shorted wiring.
Replace the fuse after finding why it blew.
Replace the switching valve or control solenoid if faulty.
Clear the codes and recheck after a cold start.

Repair cost

0–500

500–2,000

2,000–5,000

5,000+

In Saudi riyals; the highlighted part is the expected range for this fault.

The cost is low for a connector or wiring repair, and rises when the switching valve itself is replaced.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026

Frequently asked questions

Does this code mean the pump has failed?

No. This code covers the switching valve circuit; the pump and its relay circuit have a separate code such as P0418.

Can I drive with this code?

Yes. It does not affect engine performance, but repair it before an emissions test.

This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.

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