2003 BMW 325i Air Pump Replacement Cost

The air pump can be an electrically operated or belt driven pump. The pump sends fresh air to various locations of the exhaust system via an assortment of pipes, hoses, and valves.

When the air pump is malfunctioning, the vehicle may perform normally. However, it may fail an emissions inspection and the Check Engine Light may illuminate with a code set for the secondary air injection system.

When the air pump is malfunctioning, the vehicle may perform normally. However, it may fail an emissions inspection and the Check Engine Light may illuminate with a code set for the secondary air injection system. An abnormal noise may be noted from a failing air pump.

In most cases you should be able to drive a vehicle with an air pump concern. The exception would be a belt driven pump that will no longer turn, this will cause the belt to overheat and break, potentially knocking the other belts off when it breaks. If a belt driven air pump is excessively noise, the vehicle should not be driven. Chances are a noisy pump will stop turning sooner that later, leading to a broken belt.

Under normal conditions and vehicle life, you should not expect to replace an Air Pump. If an air pump has been damaged by water intrusion the cause of the problem must be corrected prior to replacing the pump. A revised intake tube and or baffle may be available. If not, make sure any the vehicle was originally equipped with are properly installed.

Illumination of the check engine light would lead to retrieval of a fault code indicating a problem with the Secondary Air Pump. An abnormal noise from the pump would also indicate a problem.

An air injection system trouble code isn't always triggered by a defective air pump. It can also be triggered by a restricted passage or air pipe, a defective check valve, a defective air pump relay, or a wiring problem.

Once the belt is removed or the electrical connector is disconnected, the pump is unbolted from its mount and the new pump is installed. If the pump is belt driven, the belt will then be installed and adjusted as necessary (replace the belt if an inspection deems it necessary). With an electric pump, the electrical connector should be checked for any damage and repaired as necessary prior to reconnecting it. Here are the full steps to replace each type of air pump: Electric Air Injection Pump

1. Disconnect the negative battery terminal
2. Remove any components that obstruct access to the electric air pump
3. Disconnect any air hoses and electrical connectors
4. Remove the fasteners that secure the air pump
5. Remove the air pump and install the new one
6. Secure the new air pump with its fasteners
7. Reconnect all electrical connectors and air hoses
8. Install any other removed components
9. Reconnect the negative battery terminal and clear any codes
10. Perform a Drive Cycle Test Drive to verify the repair

Belt Driven Air Injection Pump

1. Disconnect the negative battery terminal
2. Remove any drive belts that block access to the air pump
3. Disconnect any air hoses and electrical connectors
4. Loosen the air pump fasteners and remove the air pump
5. Install the new air pump and secure its fasteners
6. Reconnect any air hoses and electrical connectors
7. Install any removed drive belts and reconnect the negative battery terminal
8. Clear any codes and perform a Drive Cycle Test Drive to verify the repair

When replacing the air pump, be sure to perform a thorough inspection of the air injection components and passages. Always use factory parts and check for any needed software updates for the power train control module (PCM).