Air pump. Porsche 986 Boxster / 996  ❭  99660510404

Air pump
This OE Match secondary air injection pump (SIR pump) is an emissions control component designed for Porsche 986 Boxster and Porsche 911 (996) models. It forms part of the secondary air injection system, which pumps fresh air into the exhaust system during cold engine start-up to help reduce emissions.

Fits:
Porsche 986 Boxster / Boxster S 2000 - 2004
Porsche 996 C2 /C4 / C4S 2000 - 2005
Porsche 996 Turbo 2001 - 2005

Diagram ref no 1

This part supersedes earlier Porsche part numbers: 99660510400, 99660510401.

The secondary air injection pump, often referred to as a SIR pump or air injection pump, is a key component in the engine emissions system. It operates primarily during cold starts, forcing fresh air into the exhaust manifold. This additional oxygen helps burn remaining fuel vapours in the exhaust gases before they pass through the catalytic converters.

The OE Match secondary air injection pump follows the original Porsche design specifications for airflow capacity, electrical connections and mounting points. This ensures the pump works correctly with the vehicle’s engine control unit (ECU) and secondary air valves.

When the engine is started cold, the pump injects fresh air into the exhaust system. The extra oxygen promotes more complete combustion of residual hydrocarbons in the exhaust stream and allows the catalytic converters to heat up faster.

This process significantly reduces cold-start emissions and helps the vehicle meet environmental regulations.

Function
•  Secondary Air Injection: Pumps fresh air into the exhaust system during cold start
•  Emission Reduction: Helps burn unburned hydrocarbons in exhaust gases
•  Catalytic Converter Warm-Up: Accelerates catalyst operating temperature
•  Engine Management Integration: Works with ECU and secondary air valves

Secondary air pumps operate during every cold start and are exposed to moisture, temperature changes and exhaust gases. Over time the internal motor or pump mechanism may fail, which can trigger a check engine light and increase emissions output. Replacing a faulty pump restores proper operation of the emissions system and ensures efficient engine performance.

When to Replace.  Consider replacing the secondary air pump if you notice:
•  Check engine light related to secondary air injection faults
•  Unusual whining or whistling noise during cold start
•  Rough idle during cold start
•  Vehicle fails emissions testing

Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

99660510404

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