P2440 on Lexus
Secondary Air Injection System Switching Valve Stuck Open (Bank 1)
P2440 on Lexus vehicles indicates secondary air injection system switching valve stuck open (bank 1). Au7o has documented this code across 1 Lexus model — most commonly on GX. P2440 indicates the secondary air injection (SAI) system's switching/diverter valve on engine bank 1 is stuck open. The secondary air system briefly pumps fresh air into the exhaust at cold start so the catalytic converter heats up and lights off faster, cutting cold-start emissions. The computer commands this valve closed once warm-up is done; if it senses the valve hasn't closed (air is still flowing when it shouldn't be), it sets this code. A stuck-open valve can let exhaust pressure or moisture back into the air pump and skews the oxygen sensor readings during warm-up. Typical repair costs on Lexus range from $800 to $3,500, depending on the specific model and root cause.
Common Causes of P2440
- •Air switching/diverter valve stuck open or seized
- •Carbon, rust, or debris fouling the valve
- •Faulty valve vacuum control solenoid or leaking vacuum line
- •Corroded or moisture-damaged secondary air pump
- •Wiring or connector faults at the valve solenoid
- •Clogged or failed combination/check valve
- •Vacuum leak preventing the valve from closing
P2440 on Lexus by Model
Lexus GX(2 issues)
- Secondary Air Injection Pump Failure2003-2009
The secondary air injection (SAI) system pump and switching valves fail due to moisture intrusion and corrosion. The SAI pump introduces fresh air into the exhaust during cold starts to reduce emissions, but the pump motor corrodes internally and the switching valves stick. This triggers a check engine light with SAI-related codes.
- Secondary Air Injection System Failure Causing Limp Mode on GX 4602010-2013
The secondary air injection system pumps air into the exhaust on cold start to light the catalysts faster. On the GX 460 it fails in two related ways. The foam filter inside the air injection pump disintegrates with age and the debris is drawn into the system, blocking the air switching valves and lines downstream. Separately, and in the large majority of failures, the diverter or air switching valve corrodes from moisture contamination. Either failure sets emissions codes and drops the vehicle into limp mode, which owners experience as a sudden dramatic loss of power on a cold morning, usually on the first drive of the day. Lexus acknowledged the defect for 2010-2013 GX 460 vehicles with the 1UR-FE engine in a Special Service Campaign (bulletin L-SB-0028-14) covering MIL-on conditions with DTC P0418, P2440, P2442 and/or P2445, under which the pump filter and air switching valves are replaced at no charge. This is the same architecture that troubles the 2010-2013 Tundra, Sequoia, and LX 570.
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View P2440 across all makes →Frequently Asked Questions
What does P2440 mean on Lexus?▼
P2440 stands for "Secondary Air Injection System Switching Valve Stuck Open (Bank 1)." P2440 indicates the secondary air injection (SAI) system's switching/diverter valve on engine bank 1 is stuck open. The secondary air system briefly pumps fresh air into the exhaust at cold start so the catalytic converter heats up and lights off faster, cutting cold-start emissions. The computer commands this valve closed once warm-up is done; if it senses the valve hasn't closed (air is still flowing when it shouldn't be), it sets this code. A stuck-open valve can let exhaust pressure or moisture back into the air pump and skews the oxygen sensor readings during warm-up. On Lexus specifically, this code is documented across 1 model.
What causes P2440 on Lexus vehicles?▼
Common causes on Lexus: Air switching/diverter valve stuck open or seized, Carbon, rust, or debris fouling the valve, Faulty valve vacuum control solenoid or leaking vacuum line, Corroded or moisture-damaged secondary air pump, Wiring or connector faults at the valve solenoid. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P2440 on a Lexus?▼
Repair costs on Lexus range from $800 to $3,500, depending on the specific model and root cause.
Which Lexus models have P2440 documented?▼
Au7o has documented P2440 on 1 Lexus model: GX.