100 Series Land Cruiser / Lexus LX 470 Troubleshooter

The 2UZ-FE uses a timing belt, not a chain, and a belt that breaks on the trail leaves you stranded. Owners treat about 90,000 miles as the replacement point, and the water pump and tensioner are normally done at the same time. If you do not have proof of the last belt job, treat it as due.

1. Service records
   Look for an invoice showing the belt, tensioner and water pump. No paperwork on a high-mileage truck means plan the job now instead of waiting for a failure.
   easy$
2. Water pump weep hole
   Shine a light at the front of the engine around the water pump and look for dried coolant crust or drips from the small weep hole. Any sign means the pump is done.
   easy$
3. Noise at the front
   Listen with a long screwdriver or stethoscope at the timing cover area and idler pulleys. A squeal or rattle that follows engine speed points to a pulley bearing or tensioner.
   medium$
4. Replace as a kit
   Common practice is belt, tensioner, idler pulleys and water pump together, often with the thermostat and front seals. The pump is easy to add once everything is already apart.
   hard$$$
5. After the job
   If a cam or crank timing code or a rough run follows a belt job, recheck mark alignment and the sensor connectors that were disturbed before blaming the parts.
   hard$$

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

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On a truck this age, the radiator, hoses, thermostat and water pump are all aging parts, and the radiator's plastic end tanks can crack. Start with the cheap checks and do not forget the fan.

1. Coolant level and cap
   With the engine cold, check the radiator and reservoir. A weak cap that does not hold pressure can cause boil-over and coolant loss.
   easy$
2. Radiator and hoses
   Look for crusty residue, wet seams or a crack at the plastic end tanks. Squeeze the hoses (cold) for soft or swollen spots. Clear any debris packed between the radiator and A/C condenser.
   easy$
3. Cooling fan or fan clutch
   With the engine hot and idling, the fan should be pulling a lot of air. A fan that spins freely with the engine off, or is quiet and weak when hot, may have a failed clutch or drive.
   easy$
4. Thermostat
   A thermostat stuck closed shows a quick temperature rise with a hot upper hose and a cold lower hose. A stuck-open one runs cool and heats poorly.
   medium$$
5. Water pump and head gasket
   Look for coolant at the pump weep hole and listen for bearing noise. Bubbles in the reservoir or white smoke point to a pressure test for a head gasket or leaking exhaust-side path.
   hard$$$

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

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Rule out the battery and the cable connections first because they are free to check. Then look at the shift position switch and the starter.

1. Battery voltage
   Resting voltage should be about 12.4 V or more. Under 12 V, charge and load-test the battery before chasing anything else.
   easy$
2. Terminals and grounds
   Clean and tighten both battery terminals and the engine ground straps. Corrosion gives the same click as a dead battery.
   easy$
3. Shift position
   Try starting in Neutral. A neutral safety switch that is worn or out of adjustment can block cranking in Park.
   easy$
4. Immobilizer and key
   If the security light stays on or flashes, try the spare key. A key or immobilizer fault can stop the starter.
   easy$
5. Starter and solenoid
   A single click with a good battery and clean cables points to the starter. Have it bench tested or replaced.
   medium$$

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A crank with no start means fuel, spark or computer permission is missing. Check the cheap items first and confirm which of the three it is before replacing parts. If a timing belt snapped, the engine often spins very easily and will not start.

1. Fuel pump prime
   Turn the key to ON and listen at the rear for the pump to hum for a couple of seconds. No sound points to a fuse, relay or the pump.
   easy$
2. Fuses and relays
   Check the fuel pump and EFI fuses and relays in the engine bay fuse box. Swap a matching relay to test.
   easy$
3. Security light
   A flashing immobilizer light while cranking means the computer is blocking fuel or spark. Try the spare key.
   easy$
4. Fuel pressure
   Connect a gauge to the rail and check pressure with the key on. Low pressure with a running pump means a clogged filter, regulator issue or weak pump.
   medium$$
5. Timing belt and crank sensor
   If it cranks too freely, suspect a broken belt. Otherwise scan for sensor codes and confirm spark at a plug with a tester.
   hard$$

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

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A stumble at idle is usually ignition or unmetered air. If the code names a single cylinder, you can usually swap parts to find the cause. Also confirm that the timing belt is in good shape and the timing marks are right if the roughness began after belt work.

1. Read the codes
   A code for one cylinder means a coil, plug or injector on that cylinder. P0300 alone is random and often a lean or vacuum problem.
   easy$
2. Plugs and coils
   Pull the coil from the misfiring cylinder and inspect the plug. Swap that coil with another cylinder and see if the misfire follows it.
   medium$$
3. Intake leaks and air filter
   Inspect the intake boot, PCV hoses and brake booster hose for cracks and make sure the air filter is seated. Listen for a hiss at idle.
   easy$
4. Throttle body and MAF
   Clean the throttle body and the MAF sensor with the correct cleaners. Do not touch the MAF element.
   medium$
5. Injector and compression
   If swaps do not move the misfire, listen to the injector with a stethoscope and run a compression test on that cylinder.
   hard$$

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

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Both banks lean together points to unmetered air or the MAF sensor. Toyota has published bulletins on lean and air-fuel sensor codes for this platform, so ask a dealer what applies to your year before replacing sensors.

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$
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$
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$
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$$
5. Exhaust leak and air-fuel sensors
   A manifold or pipe leak near the sensors can fool them. Look for soot trails and listen for a tick that fades as the engine warms before condemning a sensor.
   medium$$

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

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Toyota published a bulletin for 2006 to 2007 Land Cruisers with the 2UZ-FE covering these codes, with debris in the air injection pump contaminating the system. If your truck is a 1998 to 2005, this is a different story, so confirm your truck actually has the system before chasing it.

1. Confirm the codes
   Read stored codes and freeze-frame data. The air system only runs for a short time after a cold start, so the code can come and go.
   easy$
2. Listen at cold start
   Start the engine cold and listen for the air pump. A loud whir is a worn pump, and silence when the system should be running points to the pump, its relay or the control circuit.
   easy$
3. Inspect for debris
   Check the pump and air filter for dirt or debris. Per the bulletin approach, if debris is present, replace the pump and inspect the other components.
   medium$$
4. Switching valves
   Valve codes (P2440, P2442) point to the air switching valves. The bulletin approach is to replace them only if they are damaged, not by default.
   medium$$
5. Control driver
   If P0418 or P2445 is present, Toyota's repair path includes the control driver. This needs a scan tool and the factory procedure, so a shop may be best.
   hard$$$

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

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The LX 470 has Active Height Control, and its spheres (accumulators), pump, lines and height sensors are a known weak point as the truck ages. The most common story is a truck that sits low overnight or throws flashing lights, and the repair can be costly, so diagnose before buying parts.

1. Ride height and lights
   Park on level ground and measure all four corners. Note whether it sinks overnight and which lamps flash. A constantly flashing OFF lamp with a sagging truck points to a real fault rather than a settings issue.
   easy$
2. Normal limits
   The system will not raise a heavily loaded truck, and the switch may need a press-and-cycle of the ignition before it responds. Rule out heavy load before assuming a failure.
   easy$
3. Fluid level and leaks
   Check the AHC reservoir and use only the correct AHC fluid if you top off. Look at the pump, lines, solenoid block and each shock and sphere for wetness; a leak is a common cause of sagging.
   easy$
4. Height sensors and links
   Check that the height sensor rods are connected and the connectors are plugged in. A loose link can cause an error and a wrong height.
   medium$
5. Read AHC codes
   A basic OBD2 scanner usually will not read these codes. Use a Toyota-capable tool or the factory procedure; pump pressure and fluid pressure sensor codes are common findings.
   medium$$
6. Pump and spheres
   A pump that runs but moves no fluid needs replacing, and worn spheres cause fast sagging and a harsh ride. These are costly jobs, so confirm the diagnosis first.
   hard$$$

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The 100 Series front ball joints are sealed and cannot be greased, so they wear out with miles, off-road use and heavy loads. Sway bar links, tie rods and bushings are cheaper and also common causes. Toyota has a bulletin for a buzz or rattle in the lower front suspension.

1. Sway bar end links
   Grab each link by hand and try to move it. Any rattle or play means replace the link or bushings.
   easy$
2. Tie rod ends
   With the wheel up, rock it left and right at 3 and 9 o'clock while watching the tie rod end. Any movement in the joint means replace.
   easy$
3. Ball joints
   Rock the wheel at 12 and 6 o'clock and watch each joint. Use a pry bar under the tire to check vertical play at the lower joint.
   medium$$
4. Control arm bushings and rack mounts
   Look for cracked or torn bushings and check the steering rack mount bushings for movement. Worn mounts cause a clunk when turning or braking.
   medium$$
5. Alignment
   Replace worn parts and then get an alignment. Wander with tight joints is often alignment or tire wear.
   medium$$

Go deeper: Biggest Tires on a Stock 100 Series Land Cruiser (UZJ100)

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The 100 Series has a rack and pinion, and leaks at the rack, the high-pressure hoses and the pump are the usual sources. Pin down exactly where the fluid is coming from before buying a rack, because hoses and fittings are much cheaper.

1. Fluid level and condition
   Check the reservoir. Foamy fluid or a whining pump suggests low fluid or air. Top off only with the fluid specified for your truck.
   easy$
2. Clean and find the leak
   Clean around the pump, hoses and rack, drive a short distance, then look. Wetness at the hose ends and fittings is the cheapest fix.
   easy$
3. High-pressure and return hoses
   Inspect the hoses for seeping crimps, swelling and rubbing. Replace any that are wet or soft.
   medium$$
4. Rack ends and pinion area
   Check the rubber boots at each end of the rack. Boots swollen or wet with fluid, or fluid near the pinion where the rack meets the steering shaft, mean the rack is leaking internally.
   medium$$
5. Replace or reseal the rack
   A leaking rack is usually replaced with a remanufactured unit. Plan for an alignment afterward and flush the system so debris does not damage the new rack.
   hard$$$

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Fluid is where to start. Toyota bulletins for this platform cover shift improvements, chatter shifting out of reverse and a fifth-gear shudder, depending on the transmission and year, so check with a dealer for your specific truck.

1. Fluid level and condition
   Check the fluid level hot and on level ground per the manual. Dark, burnt-smelling or varnished fluid is the first thing to correct.
   easy$
2. Scan for codes
   A scan tool will show solenoid, speed sensor or lockup codes. Stored codes narrow the cause quickly.
   easy$
3. Drain and fill
   Replace the fluid with the type specified for your transmission. A single drain-and-fill replaces only part of the fluid, so some owners repeat it.
   medium$$
4. Rule out engine and tire issues
   A misfire or tire imbalance can feel like a shudder. Check for misfire codes and balance before blaming the transmission.
   easy$
5. Shop diagnosis
   If problems remain after fresh fluid, solenoids and the converter need testing. Use a shop that works on Toyota automatics.
   hard$$$

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The 100 Series is full-time 4WD with a center differential lock, and problems are usually the lock mechanism, its switch or the indicator. Toyota also has a bulletin on a buzzing noise from the transfer case.

1. Switch and indicator
   Operate the center lock switch and watch the dash indicator. If the light does not match what the truck is doing, suspect the switch or wiring before the mechanism.
   easy$
2. Fuses and connectors
   Check the related fuses and the connectors at the transfer case for corrosion or damage.
   easy$
3. Shift procedure
   Follow the manual's procedure for low range and for locking the center differential. Some trucks must be stopped or moving slowly to engage cleanly.
   easy$
4. Transfer case fluid
   Check the level and look for leaks at the case. Low fluid can cause noise and drag.
   medium$
5. Lock mechanism
   A lock that was seldom used can seize. Have the lock actuator and linkage tested; this may need a shop with the factory diagnostics.
   hard$$$

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Leaks usually start at the pinion seal or axle seals, and noise comes from worn bearings or gears. Check the fluid and the breather first, since both are cheap.

1. Find the leak
   Clean the housing and drive a short loop, then look. Oil around the flange is the pinion seal, oil at the wheel end is an axle seal, and oil at the cover is the gasket.
   easy$
2. Fluid level and condition
   Check the level at the fill plug. Milky fluid means water got in, and heavy metal on the drain plug magnet is a warning sign.
   easy$
3. Breather
   Make sure each differential breather is clear. A blocked breather builds pressure and pushes oil out past the seals.
   easy$
4. Noise pattern
   Note if the whine is on throttle, on coast or at a certain speed. A driveshaft u-joint or a wheel bearing can sound like a differential, so check those first.
   medium$
5. Seals and bearings
   Seals are straightforward for a shop. Gear noise needs backlash and bearing preload checked, and may need a rebuild.
   hard$$$

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Toyota published bulletins for this platform covering front brake vibration, pad rattle, rear brake squeal and parking brake rattle. Start with a visual check of pads, rotors and hardware, then look at wheel speed sensors for the ABS lights.

1. Pads and rotors
   Pull the wheels and check pad thickness and rotor surface. Deep grooves, heat spots or a lip mean the rotors need work.
   easy$
2. Hardware and slides
   Make sure the caliper slides move freely and the shims and clips are in place. A sticking slide causes uneven wear and pull.
   medium$
3. Fluid and lines
   Check level and color. Low fluid means a leak or worn pads. Look at lines and each wheel for wetness.
   easy$
4. Wheel speed sensors
   ABS or VSC lights often trace to a wheel speed sensor or its wiring. Scan for the code, then check the connector and sensor at that wheel.
   medium$$
5. ABS actuator
   A failing actuator is costly. Rule out sensors, wiring, fuses and low battery voltage before this.
   hard$$$

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On trucks from the salt belt, the rear frame rails, crossmembers and body mounts deserve the closest look. Mud and moisture trapped at the rear wheel arches also rots the body. Check before you buy or lift one.

1. Frame rails and crossmembers
   Get under it with a flashlight and tap the rear frame rails and crossmembers with a screwdriver or small hammer. Solid ringing metal is good; dull thuds and layered scale are bad.
   easy$
2. Body mounts and suspension mounts
   Check where the body sits on the frame and the rear suspension and shock mounts. Rust spreading from seams and bolts is where trouble starts.
   easy$
3. Rocker panels and rear wheel arches
   Look for bubbling paint or soft metal at the arches and rockers, and for dampness in the rear cargo area that points to leaks.
   easy$
4. Clean and protect
   Wire-brush the loose scale, treat with a rust converter, then coat with a wax or oil underbody product. Redo it periodically.
   medium$$
5. Structural repair
   If metal is perforated, get a quote for welded repair from a shop that does frame work and have them document the extent.
   hard$$$

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