P0419: Secondary Air Injection System Relay "B" Circuit
2 vehicles · 1 makes · $200-$3,000 repair
Most Reported On
P0419 is an OBD-II diagnostic trouble code meaning “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. This code is most commonly reported on 2005-2009 Toyota 4Runner, and 2010-2014 Toyota FJ Cruiser (Base, Trail Teams, Trail Teams Ultimate), with repair costs ranging from $200 to $3,000.
Common Causes
Typical Repair Cost
Based on 2 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
To diagnose P0419, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple, affordable code reader that reads and clears check engine codes. Great for quick diagnostics on any OBD-II vehicle (1996+).
- Read & clear engine codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X OBD-II Scanner
by LAUNCH
A professional-grade handheld scanner that reads all four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
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FAQ
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 $3,000, depending on the vehicle and root cause.
Which vehicles are affected by P0419?
Au7o has documented P0419 across 2 vehicle models from 1 manufacturers: Toyota.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.