P0416Secondary Air Injection System Switching Valve "B" Circuit Open
The control circuit for the bank 2 secondary air injection switching valve (Valve B) is electrically open.
Definition
The PCM drives the Valve "B" switching solenoid to route secondary air pump output into the bank 2 exhaust during cold starts and monitors the driver circuit for current flow. P0416 sets when the circuit is open — no current when the solenoid is commanded on — pointing to a failed solenoid winding, broken wiring, or a corroded connector. Driveability is unaffected, but the MIL illuminates, bank 2 cold-start emissions increase, and the vehicle will fail an emissions inspection; moisture trapped in an inoperative air path can also corrode the valve and pump over time.
Common causes
- Open winding in the Valve B switching solenoid
- Corroded or unplugged valve connector (moisture intrusion)
- Broken or chafed control wire on the bank 2 harness run
- Blown solenoid supply fuse
- Internal valve corrosion from exhaust condensation
- Faulty PCM driver (rare)
Common misdiagnoses
- Secondary air pump replaced for a valve-circuit open
- Valve A serviced instead of the bank 2 valve
- Exhaust check valves replaced for an electrical code
- PCM replaced before checking the fuse and connector
Troubleshooting steps
1.Verify supply voltage at the valve
Confirm the fuse is good and that key-on voltage reaches the Valve B connector supply terminal.
2.Measure the solenoid winding
Ohm the solenoid across its terminals; an OL reading confirms an open winding requiring valve or solenoid replacement.
3.Inspect the connector
Check for green corrosion, water, or backed-out terminals in the valve connector — the most common failure point on AIR valves.
4.Check control wire continuity
With connectors unplugged at both ends, verify under 1 ohm from the valve connector to the PCM pin.
5.Command and confirm operation
Use a bidirectional AIR test to energize the repaired circuit and confirm the valve clicks and diverts air.
6.Run the secondary air monitor
Complete a cold-start cycle and confirm the monitor passes without resetting P0416.