On 1.8L engine, fresh air is supplied to the exhaust ports of both cylinder heads through 2 ASV-I with cut-off valves. Both ASV-I units on No. 1/No. 3 and No. 2/No. 4 cylinders operate simultaneously. See Fig 1 .

On 1.6L engine, fresh air is supplied to the exhaust ports of No. 2/No. 4 cylinder sides by 1 ASV-I. An air suction valve (ASV-II) without cut-off valve is installed on the exhaust pipe and supplies fresh air to the exhaust port near the up stream portion of the oxidation catalyst.

The ASV-II without cut-off valve always operates, regardless of coolant temperature and electronic control module signal.

The ASV-I with cut-off valve is controlled by coolant temperature sensed by the thermosensor and time governed by the ECM. When coolant temperature is less than 95° (35°C), the ECM signals the solenoid valve to allow manifold vacuum to open the cut-off valve. This enables the air suction valve to operate.

The solenoid valve I remains open for a period of 123 seconds. During this time, if low vacuum condition should exist, check valve II is used to maintain vacuum at the solenoid and cut-off valves.

At the end of the 123 second period, the control module turns off the solenoid valve II signal. Vacuum is no longer supplied to the cut-off valve and air injection is terminated.

Fig 1: Air Injection System (1.6L & 1.8L Federal 2WD Models)

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

Federal 2WD Models

Use the Manual With the Right Hardware

When to See a Mechanic