Checks, in order
- Both banks or one?P0031 plus P0051 (both upstream heaters) together points to the 15 A A/F fuse or the heater relay, not two dead sensors. One code is usually the sensor.easy $ · under about $50
- Test the heaterUnplug the sensor and measure resistance across the heater pins; an open circuit confirms the sensor. Check for 12 V at the harness side with the key on.easy $ · under about $50
- Inspect the harnessOil-soaked or heat-hardened wiring near the exhaust manifold breaks inside the insulation. A cam tower leak often shows up here first.easy $ · under about $50
- Replace with DensoThe OEM upstream sensor (Denso, part 89467-0C050 on the 5.7) runs $150–250 at a dealer or less aftermarket from Denso; it is an hour's work with a sensor socket. Stay with Denso; no-name sensors are a common source of repeat codes and rough running on these engines.medium $$ · about $50 to $500
Applies to: 2nd generation Tundra, 2007 to 2021, with the 5.7L 3UR-FE V8 (most trucks), the 4.6L 1UR-FE (2010–2019) and the 4.7L 2UZ-FE (2007–2009). Engine-specific items say which engine they apply to. Assumes a stock truck.
Tools and parts for these checks
Links below are affiliate links: toyotadata earns a commission from VEVOR and, as an Amazon Associate, from qualifying Amazon purchases, at no extra cost to you. Confirm fitment for your exact truck before you order.
| ITEM | USED FOR | BUY |
|---|---|---|
| Bluetooth OBD2 scanner with live data | Reading and clearing codes and watching live sensor data | Shop on Amazon |
| MAF sensor cleaner | Cleaning the mass airflow sensor | Shop on Amazon |
| EVAP smoke leak detector, 12V | Finding vacuum and intake leaks | Shop on VEVOR |
Other emissions problems on the 2nd Gen Tundra
More 2nd Gen Tundra problems
- Burning oil smell or smoke from the engine bay after a drive, no puddle on the ground (5.7L) (Engine)
- Ticking from the engine on cold start that fades as it warms up (Engine)
- Pink crust or a drip at the front of the engine, coolant level dropping (Cooling)
- Turn the key: one click or nothing, engine does not crank (Starting & Charging)
- Brake booster motor buzzing, sinking or hard pedal, ABS/VSC/TRAC lights (Brakes)
- Gear oil on the inside of a rear wheel or on the brake backing plate (Drivetrain)
All 10 2nd Gen Tundra symptoms in the interactive troubleshooter →
General guidance from owner experience. Confirm torque specs, fluid capacities and procedures in the factory service manual. Brakes, steering and anything structural: if in doubt, have a qualified shop inspect it before driving.