Secondary Air Injection System Switching Valve B Circuit Open
The secondary air injection (SAI) system has an open circuit condition in the pump or relay control path, preventing proper air delivery to the exhaust manifold during cold starts and warm-up. This code indicates an electrical fault in the SAI circuit rather than an engine operation problem.
What You Might Notice
- No symptoms during normal driving
- Hissing or chugging noise from SAI pump or pipes
- Loud whining from SAI pump area
- Check Engine Light illuminated
- Vehicle may fail emissions testing
Most Common Causes
- 1
Broken SAI pump wiring or connectors
Corroded, burnt, or disconnected wiring and connectors in the secondary air injection circuit prevents power from reaching the pump or relay.
- 2
Defective SAI pump relay
The relay that controls power to the SAI pump has failed electrically, preventing pump activation.
- 3
Faulty SAI pressure sensor
A malfunctioning pressure sensor sends incorrect signals to the engine control module, triggering an open circuit fault.
- 4
Frozen or seized SAI pump
In extreme cold climates, moisture in the pump can freeze and jam the pump motor, creating an open circuit condition.
How to Diagnose It
- 1
Check Broken SAI pump wiring or connectors — Corroded, burnt, or disconnected wiring and connectors in the secondary air injection circuit prevents power from reaching the pump or relay.
- 2
Check Defective SAI pump relay — The relay that controls power to the SAI pump has failed electrically, preventing pump activation.
- 3
Check Faulty SAI pressure sensor — A malfunctioning pressure sensor sends incorrect signals to the engine control module, triggering an open circuit fault.
- 4
Check Frozen or seized SAI pump — In extreme cold climates, moisture in the pump can freeze and jam the pump motor, creating an open circuit condition.
How to Fix It
- 1
Inspect and repair SAI wiring and connectors
Visually inspect all wiring, connectors, and terminals in the SAI system for corrosion, burns, or loose connections. Repair or replace damaged wiring and reconnect loose connectors.
- 2
Test and replace SAI pump relay
Use a multimeter to test the relay for proper electrical continuity and switching function. Replace the relay if it fails continuity tests or does not engage when powered.
- 3
Test and replace SAI pressure sensor
Connect a diagnostic scanner to monitor the sensor signal; if the voltage reading is out of range or absent, replace the pressure sensor.
- 4
Inspect and replace SAI pump if necessary
If the pump is frozen or seized, thaw it in warm conditions or replace with a new unit. If the pump is defective, replacement is required.
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