P0419: How to Diagnose & Fix — Secondary Air Injection System Relay "B" Circuit
3 vehicles · 1 makes · $200-$4,000 repair
How to diagnose and fix P0419: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
Toyota Tundra · 2005–2013
The secondary air injection pump is prone to failure due to water intrusion. The electric motor is located in the wheel well with moisture exposure, and the rubber boot covering the motor traps water, causing the pump to short circuit. This triggers check engine lights with codes P2440, P2443, P2445, P2447, P0418, or P0419. Some vehicles may enter limp mode.
Common Symptoms
- Check engine light illumination
- Jet engine noise on cold startup
- Decreased fuel economy
- Limp mode activation
- Rough idle when cold
How to Fix
Toyota extended warranty coverage on the air injection pumps and air switching valves for 2007-2010 models, and Warranty Enhancement Program ZG6 covers moisture-related air injection pump/switching valve failures on certain 2011 Tundras. Repair costs range from $2,000-$4,000 for OEM replacement. Some owners opt for aftermarket bypass kits with block-off plates.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Toyota 17610-0S010 genuine secondary-air pump assembly
replace the corresponding pump only when active testing and the applicable Toyota program identify it as failed Fitment/availability: Cataloged for selected 2007-2013 Tundra applications; exact engine, side/quantity, DTC branch, VIN and …
- Toyota 17610-0S030 genuine secondary-air pump assembly
replace the program-matched pump after active-test confirmation, with all required valves, inlets, gaskets and calibration handled separately Fitment/availability: Cataloged for selected 2012-2021 4.6L/5.7L applications; on this card use…
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Owner tips & cautions
- TipDIY repairs can save significantly - dealer charges $2,000-$4,000 but DIY costs are typically 50-70% less
- TipConsider OEM parts for critical components like sensors and electrical parts - aftermarket can be unreliable
- TipGet a proper diagnosis before replacing parts - similar symptoms can have different causes
Sources for this issue (2)
Toyota 4Runner · 2005–2009
The 4.7L 2UZ-FE V8 used in later 4th-generation 4Runners is known for secondary air injection system failures involving the air pump and switching valves. When the system sticks or fails electrically, the truck may illuminate the check engine light and enter reduced-power or limp mode. This problem is widely documented across Toyota V8 trucks and SUVs of the era and can be very expensive when repaired with OEM components.
Common Symptoms
- check engine light
- reduced power or limp mode
- poor acceleration
- cold-start noise from air pump area
- traction and VSC lights illuminated with CEL
How to Fix
Scan for stored air injection codes and verify pump operation, valve movement, and moisture intrusion in the system. Repair usually requires replacing one or both air pumps and/or switching valves, plus related hoses or control components. Some owners use aftermarket bypass modules for off-road or out-of-warranty vehicles, but emissions legality varies by location.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Toyota 17600-0F010 secondary-air pump assembly
pump branch only when command, power, pressure and debris inspection confirm failure Fitment/availability: 2005-2009 Toyota 4Runner 4.7L 2UZ-FE bulletin branch; broader catalog fitment does not justify use without code-directed pump test…
- Genuine Toyota 25710-50022 secondary-air switching/check valve
main switching-valve branch only after the bulletin test identifies valve failure or debris damage Fitment/availability: 2005-2009 Toyota 4Runner 4.7L 2UZ-FE bulletin branch; supersedes 25710-50020 and 25710-50021 Fitment/availability: s…
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Sources for this issue (3)
Toyota FJ Cruiser · 2010–2014
The 1GR-FE's secondary air injection system, used to reduce cold-start emissions, is prone to failure. Water/condensation intrusion corrodes the air pump and air switching valves, or a broken plastic impeller sheds debris into the system, triggering the check engine light and often limp mode. It is most common in cold and wet climates and can strand the vehicle in reduced-power mode.
Common Symptoms
- Check engine light
- Reduced power / limp mode
- Loud pump noise at cold start
- Warning lights (VSC/traction) illuminated together
How to Fix
Dealer repair typically replaces the air injection pump and the air switching valve(s) (the factory fix is expensive); the related Toyota bulletins (T-SB-0333-17 for 2012 Tacoma 1GR-FE, T-SB-0160-11 for Tundra/Sequoia) do not list the FJ Cruiser. Many owners instead install a plug-and-play SAIS bypass/delete kit (e.g., Hewitt Technologies) to permanently eliminate the failure-prone components where emissions inspection allows.
Sources for this issue (3)
Find P0419 by make
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P0419 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0419 mean?
P0419 stands for "Secondary Air Injection System Relay "B" Circuit." This code indicates the PCM detected a fault in the control circuit for secondary air injection relay 'B'. This relay powers the secondary air injection pump, which forces fresh air into the exhaust during cold starts to help the catalytic converter reach operating temperature and reduce emissions. A circuit fault here keeps the system from operating correctly, mainly affecting cold-start emissions. It generally triggers the check engine light without major performance issues.
What are the most common causes of P0419?
The most common causes of P0419 are: Faulty secondary air injection relay, Open or shorted wiring in the relay control circuit, Corroded or loose relay connector, Loss of power or ground to the relay, Failed secondary air injection pump drawing abnormal current, Failing PCM (less common). The specific cause varies by vehicle.
How much does it cost to fix P0419?
Repair costs for P0419 range from $200 to $4,000, depending on the vehicle and root cause.
Which vehicles are affected by P0419?
Au7o has documented P0419 across 3 vehicle models from 1 manufacturers: Toyota.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.