Secondary Air Injection System Air Flow/Pressure Sensor Circuit Low Bank 2
P2437 indicates the secondary air injection system has detected low air flow or pressure on Bank 2 (the side opposite the primary cylinder). This code sets when the oxygen sensor detects insufficient fresh air being injected into the exhaust during cold start or idle, which prevents proper emission control.
What You Might Notice
- Check engine light illuminated
- Engine stalling at idle or during startup
- Difficulty starting the engine
- Secondary air injection pump making noise
- Poor engine performance or rough idle
Most Common Causes
- 1
Defective secondary air injection pump
The pump may have failed or is not producing adequate air pressure. This is the most common cause of low air flow codes.
- 2
Faulty one-way check valve
The check valve can stick closed or develop an internal leak, preventing air from flowing into the exhaust manifold or allowing backflow.
- 3
Defective air control solenoid valve
The solenoid may fail to open properly, restricting air flow to Bank 2 of the secondary injection system.
- 4
Faulty air pressure or flow sensor
The sensor may provide an incorrect low reading to the PCM, or wiring/connectors to the sensor may be corroded or loose.
How to Diagnose It
- 1
Check Defective secondary air injection pump — The pump may have failed or is not producing adequate air pressure. This is the most common cause of low air flow codes.
- 2
Check Faulty one-way check valve — The check valve can stick closed or develop an internal leak, preventing air from flowing into the exhaust manifold or allowing backflow.
- 3
Check Defective air control solenoid valve — The solenoid may fail to open properly, restricting air flow to Bank 2 of the secondary injection system.
- 4
Check Faulty air pressure or flow sensor — The sensor may provide an incorrect low reading to the PCM, or wiring/connectors to the sensor may be corroded or loose.
How to Fix It
- 1
Inspect and test the secondary air injection pump
Test the pump for proper voltage and operation. Listen for pump engagement during startup. Replace the pump if it does not produce adequate pressure.
- 2
Check and replace the one-way check valve
Remove and inspect the check valve for sticking or debris. Test airflow direction manually. Replace if it does not allow one-way air flow or if stuck.
- 3
Test and replace the air control solenoid
Apply voltage to the solenoid and verify it clicks and opens. Test continuity with a multimeter. Replace if it fails to energize or holds excessive resistance.
- 4
Inspect wiring and connectors
Examine all harnesses, connectors, and ground points related to the secondary air system. Clean corrosion, repair damaged insulation, and reseat loose connections.
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