P0410 Code: Secondary Air Injection (AIR) System Malfunction
The cold-start air pump system that helps heat the catalytic converter didn't pass its self-test.
At a glance
Severity: Low
- Meaning
- Secondary Air Injection (AIR) System Malfunction
- System
- Emission Controls · Powertrain
- Safe to drive?
- Yes, short term
- Typical repair cost
- $20–$1,600
- DIY difficulty
- Moderate
Many gasoline engines, especially V8 trucks and several European and Japanese models, have a secondary air injection (AIR) system: an electric pump that blows fresh air into the exhaust ports for roughly the first minute or two after a cold start. That extra oxygen burns off the rich cold-start exhaust and heats the catalytic converter quickly. The ECU checks the system by watching the upstream O2 sensors, which should go strongly lean while the pump runs, or on some engines by reading a dedicated air pressure sensor. P0410 is the general 'system didn't work' verdict, and the usual reasons are a seized pump, a failed check valve that let water into the pump, or a problem with the relay, fuse or control valve.
Can I keep driving? Safe to drive; the engine runs normally once warm because the system only works during cold starts. The main consequences are higher cold-start emissions and a failed emissions test.
How to read P0410
- P Powertrain
- 0 Generic (SAE)
- 4 Auxiliary emission controls
- 10 Specific fault
Symptoms
- Check engine light on, typically noticed after a cold morning start
- No humming or whirring from the engine bay in the first minute after a cold start
- Or a loud, rough grinding or howling noise from the pump at cold start
- Blown fuse for the air pump, sometimes repeatedly
- Otherwise normal driving
- Failed emissions test or incomplete secondary air monitor
Possible causes
Ranked by how often each cause is behind this code (editorial estimate).
- Air pump seized or worn out, often after water got inside it
- Check valve (combination valve) stuck or leaking exhaust and condensate back toward the pump
- Blown fuse or failed pump relay
- Cracked, melted or disconnected air hoses between pump and valves
- Vacuum or electric control valve not opening the air path
- Carbon-blocked air passages in the cylinder head or exhaust manifold
Diagnosis step by step
Listen at a true cold start
Let the car sit for several hours, ideally overnight, then start it with the hood open. A working pump makes a steady hum or whir for about 30 seconds to 2 minutes, then shuts off. Silence points to the pump, fuse or relay; a harsh grinding noise points to a failing pump.
Tools: Flashlight
Command the pump with a scan tool
Many bidirectional scan tools can switch the air pump and control valve on. If the pump runs when commanded, the pump and its power supply are fine and the air path or valves are the suspects.
Tools: OBD-II scanner
Check the fuse, relay and pump power
Air pumps draw a lot of current, so check the dedicated fuse (often 30–60 A) and the relay. With the pump commanded on, you should measure close to battery voltage at the pump connector; voltage present but no pump operation means the pump is dead.
Tools: Multimeter
Look for water in the pump outlet
Pull the hose off the pump outlet. Water, rust or black soot inside means a check valve has been letting exhaust and condensate back into the system; replace the check valve along with the pump or the new pump will fail too.
Tools: Screwdriver, Flashlight
Watch the O2 sensor response
On a cold start, graph the upstream O2 sensors while the pump runs. They should drop well below about 0.2 V (or show a much leaner lambda on wideband sensors) within seconds; if the pump runs but the sensors stay rich, the air isn't reaching the exhaust.
Tools: OBD-II scanner
Clear and complete the monitor
After repairs, clear the code and let the car sit long enough for a genuine cold start. The secondary air monitor usually runs only once per trip at cold start, so it may take a couple of mornings to show 'complete'.
Tools: OBD-II scanner
Where the parts are
- 1Upstream O2 sensor
- 2Catalytic converter
- 3Downstream O2 sensor
- 4Diesel particulate filter
- 5Turbocharger
Repair options & costs
| Repair | DIY? | Estimated cost |
|---|---|---|
| Replace air pump fuse or relay | Yes | $20–$120 |
| Replace cracked air hoses | Yes | $60–$250 |
| Replace check (combination) valve | No | $150–$450 |
| Replace secondary air pump | No | $350–$950 |
| Replace pump and both check valves together | No | $700–$1,600 |
Rough US estimates for parts and labor; shop rates vary by region. Not a quote.
Notes by brand
Chevrolet
GM full-size trucks and SUVs with the V8 AIR system (Silverado, Tahoe, Suburban and their GMC counterparts of the 2000s) are well known for P0410. Water and condensate reaching the pump seize it, which often blows the fuse or damages the relay as well, so inspect the check valves whenever you replace the pump.
Toyota
Toyota Tundra and Sequoia V8s and several Lexus models use a secondary air system that commonly fails at the air switching valves and pump. These usually set P2440-series codes alongside or instead of P0410.
Field data
| Subaru | 5 | Impreza, Forester, IMPREZA WRX/STI |
|---|
Source: NHTSA Complaints API (US government open data), analyzed by DTC mention.
Emissions / smog test impact
Will fail
In states with OBD-based smog checks, P0410 with the check engine light on fails the test, and after clearing the code the secondary air monitor stays 'not ready' until the car completes cold starts. Many states allow only one incomplete monitor on newer vehicles.
Frequently asked questions
What does the secondary air pump actually do?
For a short time after a cold start, it pumps fresh air into the exhaust ports. The oxygen burns leftover fuel in the exhaust, cutting cold-start emissions and heating the catalytic converter to working temperature much faster.
Why did my air pump fail?
Most often because moisture got in. When a check valve leaks, hot exhaust and condensate reach the pump, rust its bearings and seize it. Water can also enter through a poorly placed inlet hose on some vehicles.
Can I just leave P0410 alone?
The engine won't be harmed, but the check engine light stays on, so you'll fail an OBD smog check and you won't notice if a more serious code appears. Deleting the system is emissions tampering.
Why doesn't the pump run when I start the engine warm?
That's normal. The system only operates within a coolant temperature window after a cold start, so testing must be done after the engine has cooled fully or by commanding the pump with a scan tool.
Sources
- SAE J2012 – Diagnostic Trouble Code Definitions
- ISO 15031-6 – Road vehicles, diagnostic trouble code definitions (EOBD)
- US EPA – On-Board Diagnostics (OBD) program
- Manufacturer public service information (cross-checked)
- NHTSA Complaints API
- Methodology: How We Build Code Pages · Data Sources We Use · Editorial Policy