Tundra · Diagnostic readout
Toyota Tundra Check Engine Light: Common Causes, Codes & Fixes
What it isThe Tundra's computer logged a fault — on the 5.7L V8, secondary air injection (AIR) is a known one
SeverityModerate
Safe to drive?Steady light: OK short-term — hold off towing/hauling. Flashing: stop — active misfire
Typical cost$0 gas cap to $1,000+ AIR pump
Fix it
- Scan the code first
OBD2 reader or free parts-store scan — it names the system at fault.
- Check the gas cap
Tighten until it clicks; replace a cracked seal. Cheapest, most common trigger.
- Repair what the code points to
O2/air-fuel sensor, plugs/coils for a misfire, or the AIR switching valve on a P2440-series.
- Clear it and confirm
Clear the code with the scanner and check the light stays off over a few drives.
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On a Tundra the check engine light means the engine computer logged a trouble code. Steady = a stored fault to diagnose within a few days; flashing = an active misfire that dumps raw fuel into the exhaust, so ease off and protect the converters.
Usual triggers: a loose gas cap (EVAP), an aging oxygen / air-fuel sensor past ~100k, an ignition misfire from V8 plugs or coils, a MAF / vacuum leak, and the Tundra’s signature — secondary air injection (AIR) faults on the 5.7L V8 (P2440/P2441/P2442, valve sticks or corrodes). Read the code first.
The secondary air injection story
The AIR system pumps fresh air into the exhaust for the first minute or so after a cold start, so the catalytic converters heat up faster. On the 2007–2013 second-gen trucks with the 4.6L and 5.7L V8 (same hardware as the Sequoia), the pump and switching valves sit where moisture collects. They corrode, the valves stick, the system fails its self-test, and the ECU logs P2440, P2441, P2442, or P2445.
It’s an emissions fault, not a mechanical one. The truck drives fine. But the light stays on until the repair is done, and it won’t pass inspection with the code stored. Toyota ran a warranty-enhancement program covering AIR components on many early second-gen trucks — have a dealer run your VIN before spending a dollar. If you’re paying out of pocket: OEM pump plus valves at a dealer starts north of $1,000. Aftermarket switching valves or a rebuilt pump cut that considerably.
Other common Tundra codes
P0300 is a random misfire; P0301–P0308 name the cylinder. On the V8 that’s usually a coil or plugs — one coil per cylinder, so swap-test before buying eight. P0171 / P0174 = lean condition, typically a dirty MAF or an intake leak. Air-fuel and O2 sensors get lazy past ~100k and throw slow-response codes. EVAP faults start at the gas cap and work inward. Full definitions on the code list.
By generation, and what it costs
1st gen (2000–2006): 4.7L 2UZ-FE V8 or 3.4L V6. Durable engines; the codes here skew toward O2 sensors, EVAP, and plain age. 2nd gen (2007–2021): 4.0L V6, 4.6L and 5.7L V8 — this is where the AIR issue lives, concentrated in 2007–2013. 3rd gen (2022+): 3.4L twin-turbo i-FORCE V6 and i-FORCE MAX hybrid on a new platform. No AIR pump, so that failure map doesn’t apply.
Ballpark costs: gas cap $0–20 · O2 / air-fuel sensor $150–350 · coils and plugs scale with how many cylinders need them · AIR pump or valve $1,000+ at a dealer, less aftermarket. See how the Tundra stacks up on the check engine light by model data.
Steady light: drive normally but hold off on heavy towing or hauling until diagnosed — a misfire or sensor fault worsens under load. Flashing: stop driving hard. See the check engine light overview and the common codes list.
Related codes
P0300P0171P2440P2441
FAQ
What are the most common check engine light causes on a Toyota Tundra?
A loose gas cap, oxygen/air-fuel sensors, ignition coils or spark plugs causing a misfire, and on the 5.7L V8 the secondary air injection (AIR) system. Reading the code tells you which to chase first.
What is the secondary air injection code on a Tundra?
Many Tundras log P2440/P2441/P2442 for the secondary air injection (AIR) switching valve or pump, which can stick or corrode. It's emissions-related; the truck still runs, but it should be repaired to pass inspection and clear the light.
Is it safe to drive my Tundra with the check engine light on?
A steady light is usually fine for short, normal driving. Avoid heavy towing or hauling until you know the cause, and stop driving hard if the light is flashing — that's an active misfire.
Will the check engine light reset itself on a Tundra?
If the fault was temporary, such as a loose gas cap, the light can clear after several drive cycles. A stored fault needs to be repaired and the code cleared with a scanner.
How much does it cost to fix the secondary air injection on a Tundra?
Dealer repair with an OEM pump and valves runs $1,000 and up. Aftermarket switching valves or a rebuilt pump cost a lot less. Before paying anything, have a dealer run your VIN — Toyota's warranty-enhancement program covered AIR repairs on many early second-gen trucks.
Which Tundra years have the secondary air injection problem?
Mainly the 2007–2013 second-gen trucks with the 4.6L or 5.7L V8, which share the system with the Sequoia. The 2022+ third gen runs a twin-turbo V6 with no AIR pump, so the issue doesn't carry over.