100 Series Land Cruiser / Lexus LX 470: Check engine light with P0171, P0174 or air-fuel sensor codes (P2195, P2197)

Checks, in order

1. Air filter and intake tube
   Make sure the filter is seated and that the intake tube between the MAF and throttle body is intact. Air entering after the MAF is not measured.
   easy $ · under about $50
2. Clean the MAF sensor
   Use only MAF cleaner on the element and let it dry. Replace the sensor if the codes come back.
   easy $ · under about $50
3. Vacuum and PCV hoses
   Check the PCV hose, brake booster hose and small vacuum lines for cracks, and make sure the oil filler cap seals.
   easy $ · under about $50
4. Fuel pressure
   Low pressure from a clogged filter or weak pump can cause lean codes on both banks. Test at the fuel rail.
   medium $$ · about $50 to $500
5. Exhaust leak and air-fuel sensors
   A manifold or pipe leak near the sensors can fool them. Look for soot trails and listen for a tick that fades as the engine warms before condemning a sensor.
   medium $$ · about $50 to $500

Applies to: US-market UZJ100 Land Cruiser and Lexus LX 470, 1998 to 2007, with the 2UZ-FE 4.7L V8 (timing belt). AHC items apply to the LX 470 only; most US Land Cruisers have conventional shocks. Transmission is the A343F or A750F depending on year, so check the fluid spec for your truck.

Tools and parts for these checks

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Go deeper

• Toyota 2UZ-FE 4.7 V8: Specs, Reliability & High Mileage Guide

The same problem on other Toyotas

• 5th Gen 4Runner (2010–2024): Check engine light with P0171 or P0174, system too lean
• FJ Cruiser (2007–2014): Check engine light with P0171 or P0174 (system too lean)
• Lexus GX 470 (2003–2009): Check engine light with P0171 and P0174 (both banks lean)

Other fuel & ignition problems on the 100 Series Land Cruiser / Lexus LX 470

• Engine cranks normally but won't start
• Rough idle, stumbling or a misfire code (P0300 to P0308)

More 100 Series Land Cruiser / Lexus LX 470 problems

• Timing belt due, squeal or rattle from the front of the engine, or coolant and oil weeping at the front (Engine)
• Engine temperature gauge climbing, overheating or losing coolant (Cooling)
• Turn the key: click or nothing, engine won't crank (Starting & Charging)
• Check engine light with secondary air injection codes (P2440, P2442, P2445, P0418), whirring at cold start (Emissions)
• LX 470: AHC lights flashing, truck sagging, uneven ride height or won't raise (Steering & Suspension)
• Clunk, rattle or wander in the front suspension (Steering & Suspension)

All 15 100 Series Land Cruiser / Lexus LX 470 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.