System Diagnosis - Secondary Air Injection

Diagnostic Chart:

Wiring Diagram:

Circuit Description

A fused ignition voltage is supplied to the AIR relay. The Vehicle Control Module (VCM) controls the AIR pump by grounding the AIR relay control circuit. This energizes the relay and supplies voltage to the AIR pump clutch. When the fuel system goes to the Closed Loop mode, the VCM opens the ground to the AIR control circuit.

Diagnostic Aids

An intermittent may be caused by a poor connection, rubbed through wire insulation, or a broken wire inside the insulation.

Check for the following conditions:

^ Poor connection or damaged harness-Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connection, and a damaged harness.

^ Worn or loose AIR pump drive belt

^ Pinched, kinked, or restricted AIR pipes, hoses, or fittings

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

2. This step will determine if the VCM is capable of controlling the AIR system.

5. This step will ensure that the VCM is capable of turning the AIR pump OFF.

10. This step will determine if there is a problem in the circuit between the AIR relay and AIR pump clutch ground.

16. This step will determine if the problem is in the AIR relay control circuit or the VCM.