What is P0418 fault code? What is the description of Secondary Air Injection System Relay “A” Circuit Malfunction? How can you fix the P0418 fault? What are the causes and symptoms for the P0418 fault code
What is the P0418 Fault code? What does it signify?
Modern cars have many systems that work together to maintain a smooth engine. Secondary air injection (SAI), which is responsible for supplying fresh air to the exhaust system, reduces emissions. This system helps the catalytic conversion reach its operating temperature while the engine is running in many vehicles.
What does the P0418 code mean? “Secondary Air Injection System Circuit Relay “A” Circuit Malfunction . SAI systems may use multiple relays. This code refers to the relay. “A” The associated circuit. The vehicle’s repair manual will tell you which relay is marked “A”.
An SAI system is available for vehicles that reduce harmful oxidation emissions. This system uses an electric or belt-driven motor. The pump pulls in ambient air and compresses it to a certain extent. This compressed air is then directed to the catalytic converter or exhaust manifolds. Your vehicle’s powertrain controller module (PCM), controls various valves in order to regulate and distribute air.
The PCM monitors the system pressure fluctuations using voltage signals from one or several pressure sensors. The PCM opens valves electronically and lets secondary air enter the exhaust system when the system pressure falls below a certain level. SAI pump activation also takes into consideration engine temperature, vehicle speed, and engine speed.
If the vehicle is equipped with an electric pump, the PCM monitors and activates it as required. The system relay transfers the battery voltage from fuse panel to SAI pump. If the PCM is unable to receive a voltage signal (labeled circuit A), a code P0418 will trigger.
P0418 fault codes can be found on vehicles made by many manufacturers, including Audi, BMW and Lexus models.
What causes the P0418 Fault code?
Below are some reasons to set fault code P0418:
- – Relay “A” for defective secondary air injection system
- – Damaged, frayed and fused wires to secondary air injection system relay/circuit. Loose and rusty connectors. Open or short circuit issues
- Pump failure in secondary air injection system
- – SAI System blown fuse
- – The PCM is not functioning properly or requires software updates
What are the Signs and Symptoms of Malfunction Code P0418?
You may experience the following symptoms if your vehicle has the code P0418:
- – Illumination and control of the check engine light
- SAI system is not working
- – Increased exhaust emissions
- – PCM can limit the engine’s power by putting it in fail-safe mode (Limp)
How do I fix the P0418 fault code?
Check if the pump has frozen as water ingress is a common problem for SAI pumps. To prevent further damage to the electrical system or components of the SAI system, wait until the frost has thawed if the pump is suspected to have frozen.
There are several repairs that can resolve the P0418 fault code.
- – Replacing faulty one-way safety valves
- – Replacement of damaged, burned, or melted cables
- Repair or replacement of loose or rusty connectors
- – Repair of short or open circuit problems in SAI circuit “A”
- – Replacing the defective relay “A”
- – Replacing blownfuses
- – Repairing a defective secondary air injection pump
How serious is the P0418 Fault code?
Fault code P0418 doesn’t require immediate intervention. This code is not intended to affect the engine. It only reduces exhaust emissions. It is important to have it repaired as soon as possible in order to prevent polluting the atmosphere.
