OBD-II code · Powertrain (generic, extended)
P2440 Secondary Air Injection System Switching Valve Stuck Open (Bank 1)
The switching/check valve in the secondary air injection plumbing on bank 1 is stuck in the open position. With the valve permanently open, exhaust gas can back-feed into the air pump and corrode it, while the downstream O2 sensor sees ambient air constantly.
Is it safe to drive with P2440?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySwitching valve stuck open by carbon or corrosion
- Less likelyCarbon or debris buildup preventing free movement
- Less likelyComponent wear with age - mechanical play
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–2.5 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Secondary Air Switching Valve, Secondary Air Pump
Related codes
- P2442Secondary Air Injection System Switching Valve Stuck Open (Bank 2)
- P243DParticulate Filter Regeneration Duration Bank 2
- P243EParticulate Filter Regeneration Incomplete Bank 2
- P243FParticulate Filter Restriction Soot Accumulation Too High Bank 2
- P2441Secondary Air Injection System Switching Valve Stuck Closed (Bank 1)
- P2443Secondary Air Injection System Switching Valve Stuck Closed (Bank 2)
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.