Hoses / Pipes / Sleeves

Air Injection Hose. 

The Genuine Porsche Air Injection Hose (Part Number 9A111333900) is an original equipment replacement component designed to maintain efficient airflow within the secondary air injection system on selected Porsche Boxster and Cayman models.

Fits:

• Porsche Boxster 987 MKII 2.9L 2009-12
• Porsche Cayman 2.9L 987C MKII 2009-12  

Diagram Ref No 10

Manufactured to Porsche's original specifications, this air injection hose provides a secure connection within the secondary air injection circuit, allowing fresh air supplied by the secondary air pump to reach the relevant engine emissions control components.

The secondary air injection system plays an important role in reducing harmful exhaust emissions during engine cold starts. By introducing additional oxygen into the exhaust stream, the system helps promote the oxidation of unburned hydrocarbons and carbon monoxide while supporting faster catalytic converter warm-up.

The air injection hose must maintain an effective connection to ensure the system can deliver the required airflow during operation. Exposure to engine heat, vibration, moisture and repeated temperature changes can gradually weaken the original hose and its fittings.

Over time, the hose may become brittle, cracked, split or detached, allowing pressurised air to escape and reducing the effectiveness of the secondary air injection system. A damaged hose may contribute to increased cold-start emissions, unusual air pump noises or engine management warning lights.

Replacing a worn or damaged air injection hose with a Genuine Porsche component helps restore correct airflow, maintain the integrity of the emissions control system and support reliable engine operation.

Ideal for secondary air injection system repairs, emissions-related fault diagnosis, preventative maintenance and Porsche engine servicing.

What This Product Does:
The air injection hose is a connecting component within the engine's secondary air injection system, which operates primarily during specific cold-start conditions.

Its main functions include:

• Transfers Secondary Air: Carries fresh air from the secondary air injection pump towards the associated air distribution components.
• Supports Cold-Start Emissions Control: Helps supply oxygen to the exhaust system during the engine's warm-up phase.
• Reduces Harmful Exhaust Emissions: Supports the oxidation of unburned hydrocarbons and carbon monoxide during cold starts.
• Assists Catalytic Converter Warm-Up: Helps create conditions that promote faster catalytic converter light-off and effective emissions treatment.
• Maintains Correct Airflow: Provides a sealed passage for the air supplied by the secondary air pump.
• Prevents Air Leakage: Helps prevent the loss of secondary air pressure through damaged connections or deteriorated hose material.
• Accommodates Engine Movement: Allows for normal vibration and small movements between connected engine components.
• Supports Engine Management Operation: Helps the secondary air injection system deliver airflow when commanded by the engine control unit.
• Maintains Factory Emissions Configuration: Replaces the original air injection hose using Porsche's specified component design.

Symptoms Of Wear Or Failure:
The air injection hose operates in a demanding engine compartment environment where heat, vibration and repeated temperature changes can contribute to material deterioration.

Common symptoms of a worn, damaged or leaking air injection hose include:

• Engine Management Warning Light: A secondary air injection system fault may trigger the check engine light.
• Secondary Air Injection Fault Codes: Diagnostic trouble codes relating to insufficient secondary air flow, such as P0410, P0411 or manufacturer-specific equivalents, may be recorded.
• Cracked or Split Hose: Visible cracks, splits or damaged sections of the hose may allow air to escape.
• Brittle or Hardened Material: Ageing and prolonged heat exposure can cause the hose to lose flexibility.
• Loose or Detached Connections: Damaged retaining clips or hose ends may prevent the hose from remaining securely attached.
• Unusual Cold-Start Noises: A leaking or detached hose may produce a hissing or rushing-air sound while the secondary air pump operates.
• Reduced Secondary Airflow: Leaks or restrictions can prevent the correct volume of fresh air from reaching the emissions control system.
• Emissions Test Failure: A malfunctioning secondary air injection system may contribute to emissions-related inspection problems.
• Damaged Hose Fittings: Cracked connectors or worn retaining features may allow air leakage at the connection points.
• Heat or Abrasion Damage: Contact with surrounding engine components may cause chafing, deformation or localised wear.
• Visible Hose Displacement: The hose may no longer follow its original routing or may have become disconnected during previous repairs.

Why Replacement Matters:
Replacing a worn or damaged secondary air injection hose is important for maintaining the correct operation of the vehicle's emissions control system.

Key Benefits of Replacement:

• Restores Secondary Airflow: Helps maintain the intended flow of fresh air through the secondary air injection circuit.
• Reduces Air Leakage: Replaces cracked or damaged hoses that allow pressurised air to escape.
• Supports Cold-Start Emissions Control: Helps the secondary air injection system operate effectively during engine warm-up.
• Protects Emissions System Performance: Supports the intended operation of the catalytic converter warm-up process.
• May Resolve Airflow-Related Faults: Can correct secondary air injection fault conditions where a leaking or damaged hose is confirmed as the cause.
• Maintains Secure Connections: Restores proper hose fitment and retention within the air injection system.
• Reduces Unwanted Airflow Noise: Helps eliminate hissing or rushing-air noises caused by hose leaks.
• Genuine Porsche Quality: Manufactured to the original equipment specifications for the applicable application.
• Correct Factory Fitment: Designed to match the intended hose routing and connection arrangement.
• Supports Long-Term Reliability: Helps prevent recurring problems associated with deteriorated hose material.
• Ideal for Preventative Maintenance: Suitable for replacement when the hose is found to be cracked, damaged or excessively brittle during servicing.
• Supports Emissions Compliance: Helps maintain the factory emissions system in the condition required for correct operation.

Although the secondary air injection hose is a relatively small component, it performs an important role within the vehicle's emissions control system.

A damaged or disconnected hose can interrupt the delivery of secondary air, potentially resulting in increased cold-start emissions and engine management faults.

Replacing the hose with a Genuine Porsche component helps restore the designed airflow path and reduces the risk of continued air leakage.

Related reference numbers
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9A111333900

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Fits:
Porsche Boxster 987 MKII 2009-12
Porsche Cayman 987C MKII 2009-12

Click 'Zoom in' for large parts diagram.
Diagram ref no 16

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Click 'Zoom in' for large parts diagram.
Diagram ref no 13

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