What does this code mean?
P0171/P0172 refer to bank 1; P0174/P0175 to bank 2. Lean or rich describes the controller's mixture assessment, not a direct measurement of a failed part. Compare fuel trims at idle and under load, inspect air and exhaust leaks, and test fuel supply or sensor readings using vehicle-specific limits.
Sources and interpretation [1]
A code identifies a detected condition, not a part that must automatically be replaced.
Manufacturer communications
8Original wording in English
TOYOTA
Reported code forms P0171
TSB: Some 2014 ? 2020 model year Toyota vehicles may exhibit a hard start and/or MIL ON condition with one or more of the following Diagnostic Trouble Codes (DTCs): ?DTC P0171 and/or P0174 (System Too Lean Bank 1/Bank…
TOYOTA
Reported code forms P0171
TSB: REVISION NOTICE January 23, 2020 Rev1: G1439 The Parts Information, Calibration Information, and Repair Procedure sections have been updated. SUPERSESSION NOTICE The information contained in this bulletin…
TOYOTA
Reported code forms P0171
TSB: SUPERSESSION NOTICE The information contained in this bulletin supersedes Service Bulletin No. T-SB-0058-13. Service Bulletin No. T-SB-0058-13 is obsolete and any printed versions should be discarded. Some 2009 ?…
TOYOTA
Reported code forms P0171
TSB: Some 2012 ? 2015 model year Sequoia and Tundra vehicles with the 3UR-FBE engine may exhibit a MIL ?ON? condition with Diagnostic Trouble Codes (DTCs) P0171/P0174 (System too Lean Bank 1/Bank 2), P0172/P0175 (System…
TOYOTA
Reported code forms P0171
TSB: Some 2012 ? 2015 model year Sequoia and Tundra vehicles with the 3UR-FBE engine may exhibit a MIL ?ON? condition with Diagnostic Trouble Codes (DTCs) P0171/P0174 (System too Lean Bank 1/ Bank 2), P0172/P0175…
TOYOTA
Reported code forms P0171
Some 2012 ? 2013 model year Sequoia and Tundra vehicles with the 3UR-FBE engine may exhibit a MIL ?ON? condition with Diagnostic Trouble Codes (DTCs) P0171/P0174 (System too Lean Bank 1/ Bank 2), P0172/P0175 (System too…
Check vehicle applicability
14A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
Historical vehicle association; OBD-II compatibility is not established by this record.
| Make | Model | Model year |
|---|---|---|
| Toyota | TUNDRA | 2020 |
| Toyota | TUNDRA | 2019 |
| Toyota | TUNDRA | 2018 |
| Toyota | TUNDRA | 2017 |
| Toyota | TUNDRA | 2016 |
| Toyota | TUNDRA | 2015 |
| Toyota | TUNDRA | 2014 |
| Toyota | TUNDRA | 2013 |
| Toyota | TUNDRA | 2012 |
| Toyota | TUNDRA | 2011 |
| Toyota | TUNDRA | 2010 |
| Toyota | TUNDRA | 2009 |
Historical records · 7 · Historical vehicle association; OBD-II compatibility is not established by this record.
Before replacing a part
Record codes and freeze-frame data. Check battery condition, related codes and visible wiring or hose damage. Follow the vehicle's diagnostic procedure and test results before replacing parts.
Sources and interpretation
These explanations are editorial summaries of the linked manufacturer material. PDF page numbers count from the first file page. Original publications are in English; translations are reference aids. A cited edition is not a claim that it is the manufacturer's latest instruction.
- 2024–2025 MY OBD System Operation Summary for Gasoline Engines ↗
Ford Motor Company · PDF page(s) 21, 22 ·
Source check date · 2026-10-27
Can I keep driving?
A code alone cannot establish whether driving is safe. A flashing malfunction light, severe shaking, overheating, oil-pressure warning or loss of braking or steering needs prompt attention. Stop in a safe place and seek assistance when control or engine safety is affected. Follow the vehicle handbook.