1989 Plymouth Horizon AutomaticFACTORY OEM SERVICE PROCEDURE

Air Injection System: Description

The air injection system adds a controlled amount of fresh air to the exhaust gases at the exhaust manifold, or downstream to the catalyst to aid in oxidation of the exhaust gases. This results in reduced levels of carbon monoxide (CO) and hydrocarbon (HC) emissions.

The 2.2L and 2.5L TBI system uses an Air Aspirator System (AAS). This system uses an aspirator valve, hoses and tubing.

Factory Service Tools

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

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When to See a Mechanic

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

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.