Secondary Air Injection System Switching Valve B Circuit Malfunction
The secondary air injection system's switching valve B circuit is not functioning properly, preventing the system from injecting air into the exhaust during cold start and warm-up. This can cause increased emissions and rich running conditions.
What You Might Notice
- Check Engine Light (MIL) illumination
- Increased tailpipe emissions or visible smoke
- Engine running rich (poor fuel economy)
- Failed emissions test
- Possible rough idle during cold start
Most Common Causes
- 1
Short to ground on B control circuit
The control circuit wiring is shorted to ground, preventing proper voltage delivery to the switching valve solenoid.
- 2
Open or damaged control circuit
The control circuit wiring is broken, disconnected, or severely corroded, interrupting signal delivery to the valve.
- 3
Faulty secondary air injection solenoid valve B
The solenoid valve itself is electrically open or internally failed, preventing proper operation regardless of circuit condition.
- 4
Defective relay or PCM control circuit
The relay controlling the solenoid or the PCM output driving the relay is malfunctioning or has poor connections.
How to Diagnose It
- 1
Check Short to ground on B control circuit — The control circuit wiring is shorted to ground, preventing proper voltage delivery to the switching valve solenoid.
- 2
Check Open or damaged control circuit — The control circuit wiring is broken, disconnected, or severely corroded, interrupting signal delivery to the valve.
- 3
Check Faulty secondary air injection solenoid valve B — The solenoid valve itself is electrically open or internally failed, preventing proper operation regardless of circuit condition.
- 4
Check Defective relay or PCM control circuit — The relay controlling the solenoid or the PCM output driving the relay is malfunctioning or has poor connections.
How to Fix It
- 1
Inspect and repair control circuit wiring
Visually inspect the secondary air injection solenoid B control circuit for corrosion, damage, or disconnected connectors. Repair or replace damaged wiring and clean corroded connections.
- 2
Test and replace solenoid valve B
Use a multimeter to test the solenoid coil resistance; replace if open circuit is confirmed or resistance is out of specification.
- 3
Check relay and PCM connections
Verify the secondary air injection relay is seated properly and check PCM connector pins for corrosion or damage. Test relay operation with a multimeter.
- 4
Clear code and perform system recheck
After repairs, clear the trouble code with a scan tool and perform a drive cycle to confirm the secondary air injection system operates properly.
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