Secondary Air Injection
Secondary air injection pumps fresh air into the exhaust after a cold start to heat the catalytic converter faster.
What is Secondary Air Injection?
An electric pump and a valve supply the air. It runs for about a minute after cold start. It has its own readiness monitor. Many newer engines achieve fast catalyst warm-up with timing tricks instead and no longer use a secondary air pump. Systems that are rarely used can have stuck check valves.
How it works
Extra oxygen burns remaining fuel in the exhaust, raising its temperature.
Why it matters for your car
Pump or valve faults set codes and may fail inspections. Water ingress can damage the pump.
Other terms
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- Alloy Wheel Refurbishment
- Brake Judder (Brake Vibration)
- Charging Curve
- Closed Loop (Fuel Control)
- Contact Breaker Points
- Degreaser (Engine Cleaner)
- Dual-Zone Climate Control
- Firing Order
- Flasher Relay (Turn Signal Relay)
- Galvanised Body (Zinc-coated Steel)
- Injector Leak-off Test
- Manufacturer Plate (Type Plate)
- Mechanic’s Stethoscope
- Peak Charging Power (Max kW)
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- Primer (Primer Surfacer)
- Three-Phase AC Charging
- Tyre Repair Kit (Sealant Kit)
- Window Switch