P2440 and P2442 on a 2015-2016 Toyota Tundra: Check the ECM Calibration Before Parts
JC Landry, ASE Master TechnicianPublished Oct 26, 2026 · Updated Oct 27, 2026
P2440 and P2442 mean the ECM sees exhaust pulses in the secondary air passage with the air switching valve commanded closed, on bank 1 and bank 2 of a 2015-2016 Toyota Tundra. Read every stored code first, then check the ECM calibration before replacing anything. Expect a check engine light and, on some 4.6L trucks, a limp mode that caps throttle input at about 25 mph.
Safety first
- Bring your hand to the valve port slowly; exhaust burns.
- Keep fingers off valve terminals 2, 3 and 4 on the bench check.
What does P2440 mean on a 2015-2016 Tundra?
P2440 (Secondary Air Injection System Switching Valve Stuck Open Bank 1) and P2442 (the same fault on Bank 2) judge the air switching valve for that bank; bank 1 holds the No. 1 cylinder, farthest from the transmission. After a cold start a pump pushes fresh air through the valve into the exhaust ports. The ECM builds a cumulative pulsation number from the valve assembly's pressure sensor; pulses with the valve commanded closed mean it calls the valve stuck open.
The cold-start check sets the code at 25 kPa or higher cumulative pulsation for 7 seconds, pump off and valve closed, on the 4.6L (30 kPa on the 5.7L). All of these must hold:
- Battery 11 V or more, atmospheric pressure 45 kPa or more, engine running, no driver or pressure sensor fault, both checks below completed.
- Pump-on check: 5 seconds or more since the air system started, valve open, intake air below 100 g/s (99 on the 5.7L), 400 to 3,750 rpm (below 3,550 on the 5.7L).
- Pump-off check: 10 seconds or more since the air system operated, valve closed, below 3,000 rpm (below 2,800 on the 5.7L).
- Both checks: 1 second or more since engine start.
The strong pulsation check sets it at 75 kPa or higher for 2 seconds on the 4.6L (100 kPa on the 5.7L), with:
- One of: cumulative intake air 100 g/s or more, a temperature rise of 10 degrees C (18 degrees F) or more since start, or starting coolant of 60 degrees C (140 degrees F) or higher.
- Pump off, valve closed, load 20% or more, 3,750 rpm or less (below 4,800 on the 5.7L).
- No pressure sensor fault, 1 second or more since start, 10 seconds or more since the air system operated, no stuck-open fault already detected.
The ECM stores the code and turns on the check engine light; strong pulsation is a one-trip condition. These are the original factory figures, and Toyota later changed the ECM logic by reflash.
A few sibling codes come from the same system:
- P2441 and P2443 (valve stuck closed): two trips; pulsation below 18 kPa on the 4.6L, below 10 kPa on the 5.7L for 7 seconds.
- P2444 and P2446 (pump stuck on), P2445 and P2447 (pump stuck off): two trips; pressure above 3.0 kPa (2.4 on the 5.7L) with the pump commanded off, or below 1.9 kPa (2.4 on the 5.7L) with it commanded on.
- P0412 and P0415 are valve drive circuit codes; P2431 to P2438 are pressure sensor circuit codes.
What symptoms does P2440 cause on the Tundra?
- Check engine light on.
- On some 4.6L trucks, a limp mode that limits throttle input to about 25 mph.
- Sub-freezing outside temperatures can trigger it.
What causes P2440 on the Tundra, most likely first?
Listed most likely first. The test order is in the diagnostic steps below.
| Rank | Cause | Quick confirm | Typical fix |
|---|---|---|---|
| 1 | ECM calibration not the latest | Calibration ID not the latest | Reflash; do not replace the ECM |
| 2 | Valve stuck open (debris, ice, moisture, corrosion) | Pulsation with valve commanded closed; bench check fails | Replace that bank's valve |
| 3 | Air tube blocked, damaged or loose | Look at the No. 2 and No. 3 tubes | Replace the tube |
| 4 | Vacuum hose to sensor blocked or deformed, or sensor reading off | Forced test passes, code returns; hose check | Repair or replace the hose; replace the valve if the reading is out of range |
| 5 | Driver, its power or ground, or ECM wiring | Supply, ground, wiring and signal checks | Repair wiring or power; replace driver; ECM only if signals fail |
| 6 | Air pump heater circuit, relay or pump | Heater active test; relay and supply checks | Replace relay or pump, or repair wiring |
Toyota technical service bulletin T-SB-0144-14 covers the 5.7L and T-SB-0079-16 covers the 4.6L. Both name P2440 and P2442 and call for an ECM reflash instead of a new ECM, which is cause number 1 on the list.
How do you diagnose P2440 on a 2015-2016 Tundra?
You will need a scan tool that runs the secondary air injection check.
- 1
Read every stored code.
Fix anything other than P0412, P0415 and the P2440 to P2443 family first; those stop the monitor. If P0412 or P0415 is stored with P2440 or P2442, work the valve circuit first.
- 2
Check the ECM calibration.
Confirm the code is present, then read the calibration ID on the Authorized Modifications Label. If it is not the latest, reflash the ECM with the latest calibration, update the label and road test; do not replace the ECM. The reflash needs Techstream or an approved J2534 interface, plus a battery support unit that holds voltage at 13.5 V. The 4.6L bulletin covers trucks built before a production change, and the 5.7L bulletin lists 2014-2015 trucks only. Neither bulletin names a 2016 5.7L, so on one of those the calibration check is still the cheapest first step, but the bulletin itself may not apply. If the calibration is already the latest, the bulletin does not apply, so move on.
- 3
Check the air pump heater circuit.
Unplug the pump, run the heater active test and check for supply at the heater terminal. If the terminal has supply, inspect the pump heater and replace the pump if it fails. If it has none, check the relay, its power and the wiring, and repair or replace what fails; if all of those pass, inspect the pump and replace it if it fails.
- 4
Run the forced-operation test.
If a battery cable has been reconnected, wait 7 minutes with the ignition on or the engine running first. Warm the engine, disconnect the No. 1 air hose and run the check in manual mode at idle. With the pump on, you should feel pulsation at the valve port with the valve open and none with it closed. You can also watch the cumulative pulsation reading on the scan tool; with the pump off and the valve closed it has to stay under 25 kPa on the 4.6L (30 kPa on the 5.7L), the level at which the ECM sets the code. If it pulses when it should be closed, work the air tubes, valve and driver in the next step. If it behaves, skip ahead to the vacuum hose and pressure sensor.
- 5
When the test fails, check the air tubes, then the valve, then the driver. Check the No. 2 and No. 3 air tubes for firm connections, blockage or damage; replace a bad one. Bench check the valve: no airflow unpowered, airflow with battery voltage applied. If it fails, replace the failing bank's valve (the 5.7L has one assembly). If it passes, check driver supply, ground and ECM wiring, repair what fails, then test the driver signals. Failed signals mean replace the ECM; good signals mean replace the driver. If the code returns on the recheck, replace the ECM.
- 6
When the test passes, check the vacuum hose and pressure sensor. Inspect the hose between the valve and its sensor for blockage or deformation; repair or replace it. If the data list reading is out of range, replace the valve assembly (the sensor is part of it); if it is in range, treat it as intermittent.
Get the P2440 and P2442 tests for your Tundra
The stored-code checks, calibration check, forced-operation test and valve checks above follow Toyota's own test order. Ask emanuals.ai about your Tundra and get the exact test steps, specs and procedures from the factory manual.
Specs you need for the Tundra P2440 repair
Use new gaskets. The 5.7L valve job pulls the manifolds and drains the coolant.
| 4.6L valve assembly bolts (3 each bank) | 24 N·m (18 ft·lbf) |
|---|---|
| 4.6L mounting bolts (2 each bank) | 10 N·m (7 ft·lbf) |
| Bracket bolt (4.6L harness clamp, bank 1; 5.7L) | 8.0 N·m (71 in·lbf) |
| 5.7L valve assembly bolts (3) and front water by-pass joint nuts | 21 N·m (15 ft·lbf) |
| 5.7L air tube bolts (2 each) and air tube to heat exchanger cover bolts (2) | 10 N·m (7 ft·lbf) |
| 5.7L coolant | Toyota Super Long Life Coolant or similar non-silicate, non-amine, non-nitrite, non-borate ethylene glycol with long-life hybrid organic acid technology |
| 5.7L coolant capacity | 13.0 L (13.7 US qt) with trailer towing, 12.1 L (12.8 US qt) without |
What if the obvious fix does not work?
If the first fix does not hold, look next at the driver and its power, ground and wiring, then the pump heater circuit and relay, then the vacuum hose and sensor reading. Water getting into the pump and valves can corrode or stick them, and corroded or dirty connectors, terminals and grounds in the pump and valve circuits can set these codes. A valve swap alone can leave a failing pump behind, so the light can come back, and the valve always goes in with a new gasket.
The stop point is when the valve and driver tests pass and the code returns on the recheck. At that point the ECM is next, unless the truck is in the bulletin population on an old calibration, where the reflash comes first.
How do you confirm the repair?
- Warm the engine, ignition off. Connect the scan tool, ignition on, clear codes, ignition off, wait at least 30 seconds. Then ignition on, run the secondary air injection check in automatic mode (start the engine after the tool initializes), exit and check pending codes. None is a good result.
- Open the All Readiness screen in Techstream, select the code and read the result: NORMAL is normal, ABNORMAL is a fault, INCOMPLETE means run a driving pattern after confirming the enabling conditions.
- INCOMPLETE or N/A with no pending code: run a universal trip (idle 30 seconds or more, 25 mph or more for 5 minutes or more in total, 10 minutes or more from engine start) and check permanent codes. None means normal.
- The tool runs the air system for 5 seconds at most per check, up to 4 checks per trip, with at least 30 seconds between checks. If it shows ERROR, stop the engine for 10 minutes and try again.
These are the codes that keep the monitor from running, so fix any of them first, grouped by family:
- Variable valve timing, intake and exhaust: P0010, P0020; P0011, P0021; P0012, P0022; P0013, P0023; P0014, P0024; P0015, P0025; P0016, P0018; P0017, P0019
- Cam, crank and VVT sensors: P0335; P0340, P0342, P0343, P0345, P0347, P0348; P1340; P0365, P0367, P0368, P0390, P0392, P0393
- Air fuel ratio sensor heater: P0031, P0032, P0051, P0052, P101D, P103D
- Air fuel ratio sensor: P014C, P014D, P014E, P014F, P015A, P015B, P015C, P015D, P2195, P2196, P2197, P2198, P2237, P2238, P2239, P2240, P2241, P2242, P2252, P2253, P2255, P2256
- Air fuel ratio imbalance: P219A, P219B, P219C, P219D, P219E, P219F, P21A0, P21A1, P21A2, P21A3
- Mass air flow: P0102, P0103 (P0101 also on the 4.6L)
- Manifold absolute pressure, 4.6L only: P006A, P0107, P0108
- Intake air and coolant temperature: P0112, P0113; P0115, P0117, P0118; P0125
- Throttle position: P0120, P0121, P0122, P0123, P0220, P0222, P0223, P2135
- Fuel system: P0171, P0172, P0174, P0175
- Misfire and ignition: P0301 to P0308; P0351 to P0358
- Knock sensor: P0327, P0328, P032C, P032D, P0332, P0333, P033C, P033D
- EGR, 4.6L only: P0401
- Evaporative emission pressure sensor: P0451, P0452, P0453; P106B
- Vehicle speed: P0500
- Secondary air injection pressure sensor: P2431, P2432, P2433, P2435, P2436, P2437, P2438
Questions mechanics ask about P2440 on the Tundra
What do P2440 and P2442 mean on the Tundra?+–
Both say the ECM sees exhaust pulses in the secondary air passage while it has commanded the air switching valve closed, so it calls the valve stuck open. P2440 is bank 1, the side with the No. 1 cylinder and farthest from the transmission, and P2442 is bank 2.
Can you drive a Tundra with P2442 set?+–
The code turns on the check engine light. Toyota's bulletin for the 4.6L adds that on some trucks it can bring on a limp mode that limits throttle input to about 25 mph, and that sub-freezing outside temperatures can trigger it. The bulletin for the 5.7L names debris or ice in the air switching valve assembly as the cause. Neither bulletin says whether it is safe to keep driving with the code set.
Will P2440 clear itself on the Tundra?+–
No. A valve that is still stuck open will not give a normal result, so the code stays. After the repair, clear the codes, run the confirmation check and finish a universal trip, then check permanent codes.
Is there a Toyota bulletin for P2440 and P2442 on the Tundra?+–
Yes. T-SB-0144-14 covers the 5.7L (2014-2015 trucks) and T-SB-0079-16 covers the 4.6L (2014-2016 trucks built before a production change). Both name P2440 and P2442 and call for a reflash instead of a new ECM. The 5.7L bulletin ties the codes to debris or ice in the switching valve, and the 4.6L bulletin ties them to the cold-weather limp mode.
Did Toyota's emission warranty cover the P2440 and P2442 reflash on the Tundra?+–
The bulletins described the reflash as covered under the Toyota Federal Emission Warranty for 96 months or 80,000 miles from the in-service date, whichever came first, and only for the condition described. That coverage was for the ECM reflash, not valve, pump or other part replacement, and it has ended for these model years, so plan on paying for the repair. The bulletins do show what Toyota found failing: the ECM logic on both engines and, on the 5.7L, debris or ice in the air switching valve.
Sources
- Toyota Tundra Service & Repair Manual, section Engine Control System, SFI System: P2440-P2443 Secondary Air Injection System Switching Valve (1UR-FE and 3UR-FE engines).OEM Manual
- Toyota technical service bulletin T-SB-0144-14, "Secondary Air Injection System - MIL "ON" OTC P2440 and/or P2442", 2014-2015, November 7, 2014.Service Bulletin
- Toyota technical service bulletin T-SB-0079-16, "MIL "ON" DTC P2440/P2442", 2014-2016, July 14, 2016.Service Bulletin
- emanuals.ai, Query data, "P2440 P2442 Toyota Tundra".First-Party Data
ASE Master Technician
JC spent 15+ years as a certified Master Mechanic before trading the shop for the keyboard. He's worked across dealerships, owned and operated his own independent garage, and consulted on automotive trade school curricula, reviewing technical textbooks used in vocational programs.
He now serves as Editor-in-Chief at emanuals.ai, where he oversees the platform's technical content. He's one of the few voices in automotive publishing who turned wrenches professionally for decades before he had a byline.
Ask emanuals.ai about your car
Answers come from the actual factory manual for your make, model and year, with the page cited. Join the waitlist and we will email you when a spot opens up.
Invite-only beta. No spam, one email when your spot opens.