Secondary Air Injection (AIR) System (Only Engine Control Modules (ECM) With Coding 06XXX) Checking

Secondary Air Injection (AIR) system (only Engine Control Modules (ECM) with coding 06XXX), checking

Note:
•The secondary air injection system blows air behind the exhaust valves for a certain period of time (temperature dependent) during a cold start (engine coolant temperature between +8° to +65°C).

•Activation occurs from MFI Engine Control Module (ECM) -J192- via Secondary Air Injection (AIR) Pump Relay -J299- to Secondary Air Injection (AIR) Solenoid Valve -N112- and both combination valves.

•The diagnostic consists of a flow test and a leak test

•During flow test, oxygen sensor control is switched off (engine runs rich at this time). At the same time, the secondary air injection pump is switched on. This injects fresh air into the exhaust manifold which increases the oxygen content in the exhaust gas. Oxygen sensor now measures a lean mixture. To pass test, oxygen sensor must measure a lean mixture for a certain length of time. This means that the secondary air injection system delivers enough air see if secondary air injection system OK.

Leak test
Requirement for leak test is first that flow test be OK. At idle, with engine at operating temperature, secondary air injection pump will switch on. However, combination valves are not activated by the secondary air injection solenoid valve, i.e. they remain closed. When the secondary air injection pump is switched on, oxygen sensor regulation is observed by control module. If the system does not leak, fresh air cannot enter the exhaust manifold. Oxygen sensor regulation must virtually not react (enriching or becoming lean). If the system is leaking, the oxygen sensor regulation will respond to the leaner mixture (via the oxygen from the secondary air injection) and cause a noticeable enrichment. This noticeable enrichment is recognized by control module.