The purpose of the air injection system is to reduce exhaust emissions by oxidizing hydrocarbons (HC) and carbon monoxide (CO) during cold engine operation.

The system is composed of air suction valves (I, II and/or III), thermosensor, solenoid valve I, check valve II, thermostatic air cleaner (TAC), silencer(s), revolution sensor (Federal 4WD with auto. trans.), various hoses and tubing and an electronic control module (ECM). Depending on model and application, secondary (fresh) air is supplied to exhaust ports on either one or both cylinder banks.

There are 3 types of air suction valves used with the air injection system. On all California models, the air suction valve (ASV-I) includes a cut-off valve.

Federal 1.6L models with 2WD have 1 air suction valve (ASV-I) with cut-off valve and 1 air suction valve (ASV-II) without cut-off valve. Federal 1.8L models with 2WD have 2 air suction valves (ASV-I) with cut-off valves and 1 air suction valve without a cut-off valve (ASV-II).

All Federal 4WD automatic transmission models use 1 air suction valve (ASV-I) with cut-off valve and 1 air suction valve (ASV-III) without cut-off valve. Federal 4WD manual transmission models use 2 air suction valves (ASV-III) without cut-off valves.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Air Injection System: Description

Use the Manual With the Right Hardware

When to See a Mechanic