Possible Causes:
* Air Pump (Air Injection Pump): The pump itself might be failing. It could be seized, making a whirring or groaning noise when you turn the key, or it might be completely dead. This is a common culprit.
* Air Pump Relay: The relay that controls the pump might be faulty. A simple test with a multimeter can determine if it's working correctly.
* Vacuum Lines: The vacuum lines that control the operation of the air pump or the diverter valve can crack, become disconnected, or leak, disrupting the system's function. Inspect these carefully for damage.
* Diverter Valve: This valve controls the flow of air into the exhaust system. It might be stuck open, stuck closed, or malfunctioning.
* Wiring: Check the wiring harness for any damage, shorts, or loose connections to the pump, relay, and diverter valve.
* Check Valve: A one-way check valve in the system prevents backflow; its failure could disrupt the proper functioning of the system.
* Clogged Air Injection Pipes: The pipes themselves might be clogged with debris, restricting airflow.
* Fuse: Although less common, a blown fuse related to the system could cause the code.
Troubleshooting Steps:
1. Visual Inspection: Begin by visually inspecting the air pump, vacuum lines, and wiring harness for any obvious signs of damage.
2. Relay Check: Test the air injection pump relay using a multimeter to ensure it's switching properly.
3. Vacuum Line Check: Carefully examine all vacuum lines for cracks, leaks, or disconnections.
4. Air Pump Test: Check the pump for operation; it should run when you initially turn the ignition on (you may hear it). A mechanic can perform more in-depth testing of the pump.
5. Diverter Valve Check: Inspect the diverter valve for proper operation. This often requires specific testing procedures.
6. Scan Tool Data: A scan tool (OBD-II) can provide more detailed information about the system's performance and may help pinpoint the problem area more accurately. This can show if it's a low flow problem or a pump failure.
Important Considerations:
* Cost: Replacing the air pump can be relatively expensive.
* DIY Difficulty: Some repairs, like replacing the air pump, can be challenging for someone without mechanical experience. Others, such as checking vacuum lines and relays, are easier.
* Emissions: While the SAI system is important for emissions, driving with this code may not immediately affect your vehicle's drivability, but a failing system can lead to bigger problems over time. Getting it fixed is recommended.
If you're not comfortable performing these checks yourself, it's best to take your Impala to a qualified mechanic for diagnosis and repair. They have the tools and expertise to properly diagnose and fix the problem efficiently.
