If your 2005–2015 Tacoma with the 4.0L V6 throws P2440, P2441, or P2442 and the check-engine light is on, the culprit is almost always the secondary air injection (AIR) system — typically a stuck or corroded air switching valve, sometimes the pump itself. This is one of the most common and most expensive check-engine causes on the 1GR-FE. A dealer repair with both OE valves and the pump can run $2,000–2,500; a single failed valve replaced yourself runs about $300. The system only operates for the first couple minutes of a cold start, so the truck drives fine — it is an emissions code, not a drivability emergency.
The secondary air injection system exists to clean up the exhaust during cold start. For roughly the first 60–120 seconds after a cold start, an electric pump forces fresh air into the exhaust stream through valves on each cylinder bank, helping the catalytic converters light off faster. It is a Toyota-specific design on the 4.0L, and over time corrosion seizes the valves or the pump fails — both very common, especially on 2005–2009 trucks and on any truck that sees moisture, salt, or sits a lot.
**The codes, decoded.** P2440 and P2441 point to the air switching valve (bank 1, stuck open or stuck closed); P2442/P2443 cover bank 2. P0418 and related codes can point at the pump relay or pump circuit. The ECU runs a self-check on cold start, and when the valve doesn't move or airflow isn't seen, it sets the code and the light. Pull freeze-frame data — it confirms the fault happened at cold start, which fits the AIR system.
**Why the dealer bill is brutal.** The OE fix is to replace the failed valve(s) and, if the pump is bad, the pump — all genuine Toyota parts, plus labor to reach them. Two valves and a pump in genuine parts alone approach $1,200, and the labor stacks on top. This is sticker shock for what is, mechanically, an emissions accessory.
**The realistic DIY paths.** Most failures are a single seized valve, not the pump. Diagnosing which valve failed and replacing only that one drops the cost to around $300 in parts. Some owners clean a lightly corroded valve and reset the code as a temporary measure, though a cleaned valve often re-fails. Aftermarket bypass/block-off kits exist that simulate the system to the ECU — but installing one to defeat a functioning emissions system is illegal under federal law and will fail emissions testing where required. Whether a bypass is street-legal depends entirely on your state and inspection rules; in Arizona and many areas, emissions tampering is a violation. Repair the system if your area tests emissions.
**Does it affect how the truck runs?** No, and that is the saving grace. The AIR system only operates briefly at cold start. With it disabled or failed, the truck idles, drives, and makes power normally — you are left with a check-engine light and a failed emissions test until it is repaired. There is no need to panic or stop driving.
| Part | Vendor | Est. price |
|---|---|---|
| OE secondary air injection valve (driver/passenger, each) | Toyota | ~$280 |
| Secondary air injection pump (OE) | Toyota | ~$650 |
| Aftermarket bypass/block-off kit (where emissions-legal) | various | ~$120 |
Written and maintained by an AZ wheeler and driveway wrencher. Always cross-reference your factory service manual — modifications affect vehicle safety and warranty. Work at your own risk.