What P0175 Means on Your 2020 Toyota Tundra
The P0175 code on your 2020 Toyota Tundra indicates bank 2 of the V8 engine is running rich — there's too much fuel in the combustion mixture. The 2020 Tundra (2nd generation) is available with the 1UR-FE 4.6L V8 (310 hp) or the 3UR-FE 5.7L V8 (381 hp), both naturally aspirated with dual overhead cams and port fuel injection. As a V8, bank 2 is a distinct cylinder group with its own set of O2 sensors, exhaust manifold, and catalytic converter. At 4-6 years old with 60,000-100,000 miles, wear-related sensor and fuel system issues are the primary concern.
Symptoms on Your Tundra
- Check engine light on
- Strong fuel smell from the exhaust, especially at idle
- Rough or uneven idle (more noticeable than usual on the smooth V8)
- Black soot at the dual exhaust tips
- Fuel economy drops below the already-modest 13–18 mpg rating
- Possible misfires or engine stumble under light throttle
Common Causes on the 2020 Tundra
1. Degraded Bank 2 O2 Sensor (High Likelihood)
The V8's bank 2 upstream O2 sensor controls fuel delivery for that cylinder bank. At 60,000-100,000 miles, the sensor has endured significant thermal cycling. The Tundra's V8 runs hotter than smaller engines, accelerating sensor degradation. A sensor that reads falsely lean causes the ECM to add fuel. Compare bank 1 and bank 2 sensor waveforms — a noticeable difference in switching speed or voltage bias identifies the faulty sensor. O2 sensors for the Tundra V8 run $50-$130 for quality aftermarket units.
2. Leaking Fuel Injector (Medium Likelihood)
The 4.6L and 5.7L V8s use port fuel injection with individual injectors per cylinder. After years of service, injector O-ring seals can harden and the injector pintle may not seat properly. Bank 2 has four injectors (on the 5.7L) or four injectors (on the 4.6L). A leaking injector drips fuel into its port. Pull the spark plugs from bank 2 and inspect for fuel fouling. Tundra injectors are affordable at $30-$70 each aftermarket.
3. Fuel Pressure Regulator Failure (Medium Likelihood)
The mechanical fuel pressure regulator on the Tundra's V8 maintains rail pressure using a vacuum-referenced diaphragm. After 4-6 years, the diaphragm can deteriorate. The classic test: pull the vacuum line from the regulator and check for fuel. If fuel is present, the diaphragm has ruptured. Also test fuel rail pressure — Toyota specifies approximately 44-50 psi at idle for these V8s.
4. EVAP System Issue (Low Likelihood)
A purge valve that doesn't close fully or a charcoal canister saturated from years of fuel tank overfilling can introduce excess fuel vapor into the intake. The Tundra's large fuel tank makes canister saturation a possibility if topping off has been habitual. Check for fuel smell near the canister.
Diagnostic Steps
- Identify your engine — 4.6L or 5.7L V8, as some component locations differ.
- Check for companion codes — P0172 alongside P0175 means both banks rich (fuel pressure or MAF issue).
- Compare bank fuel trims — A significant LTFT difference between banks confirms a bank-specific problem.
- Test bank 2 O2 sensor — Compare switching speed to bank 1 sensor.
- Test fuel pressure regulator — Check vacuum line for fuel and verify rail pressure.
Repair Costs for the 2020 Tundra
- O2 sensor (bank 2): $100–$280
- Fuel injector: $80–$250 per injector
- Fuel pressure regulator: $120–$280
- EVAP canister/purge valve: $100–$300
- Spark plugs: $80–$150 for a set of 8
Truck Owner Priorities
The Tundra is a full-size truck used for towing up to 10,200 lbs. Running rich while towing puts extreme thermal stress on the bank 2 catalytic converter. Converter replacement on the Tundra runs $1,000-$2,500 per side. Do not tow with an active P0175 code. Fix the root cause first — typically a $100-$280 repair — to prevent a four-figure bill down the road.
DIY Potential
The Tundra's V8 engine bay has excellent access compared to smaller trucks. Both the 4.6L and 5.7L offer plenty of room around the exhaust manifolds and fuel rail. Bank 2 O2 sensor replacement is manageable from underneath — the body-on-frame design provides good underbody clearance. Spark plug inspection is straightforward. Fuel pressure testing requires a gauge but is a simple DIY procedure. The Tundra is one of the more DIY-friendly trucks for P0175 work.