1999 model year · NHTSA recalls, manufacturer TSBs, and owner forum reports · Updated July 2026
According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 1999 Toyota 4Runner has 6 documented known issues. No issues are rated critical, indicating generally reliable ownership. Across all issues, repair costs range from $15 to $2,500. DIY maintenance guides at au7o.io.
On the 1999-2009 Toyota 4Runner, as 4Runners accumulate miles, the catalytic converter loses efficiency and the ECU sets P0420 (Bank 1) and/or P0430 (Bank 2) when the downstream O2 sensor starts to mirror the upstream sensor. On the 4th-gen 1GR-FE, the primary cats are integrated into the exhaust manifolds, which makes them prone to cracking and internal breakdown with heat and age — a frequently searched and relatively expensive repair. Misfires, exhaust leaks, or a failing rear O2 sensor can also trip the code, so diagnosis before parts replacement matters.
Diagnose before buying a cat: scan for misfire codes (P030x/P0300), check for exhaust leaks upstream, and compare upstream vs downstream O2/A-F sensor waveforms. If sensors and exhaust are healthy and the downstream signal tracks the upstream, replace the failed converter. On 4th-gen 4.0L trucks the failure is usually the passenger-side (Bank 1) manifold-integrated cat. Use OEM or a high-quality CARB-compliant converter; a common contributing fix is the Bank 1 Sensor 2 (downstream) O2 sensor (use Denso). Sensor-only fixes run $100-300; converter replacement is the expensive path.
The exact parts — OEM, plus what owners actually use. Skip the internet hunt.
Bank 1 = passenger/right side on the 1GR-FE; the primary cat is cast into the exhaust manifold, so replacement means a whole manifold-converter sub-assembly. OEM Toyota runs ~$600-640; OE-design aftermarket (Walker) ~$250-270; economy direct-fit ~$140-165. For CA/NY/emissions states use a CARB-compl
Bank 2 = driver/left side. Same manifold-integrated design as Bank 1. Only needed if the truck sets P0430 rather than (or in addition to) P0420 — the driver side fails less often than the passenger side on these. Pricing parallels the Bank 1 part.
For 2003-2006 4Runner this is the 'downstream right' sensor = Bank 1 Sensor 2. A lazy/failed rear sensor can mimic a bad cat and set P0420, so this is the sensor-only fix ($100-300 installed) to try first. Use Denso 234-4260 (the exact OE part) rather than a generic universal sensor.
Fits 2003-2011 4.0L 1GR-FE (4Runner/FJ Cruiser/Tacoma/Tundra). Buy one per manifold you pull; always replace on reassembly to prevent an exhaust leak that would itself trip a downstream-O2/efficiency code. Cheap insurance — do not reuse the old gasket.
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On the 1996-2009 Toyota 4Runner, eVAP faults (P0440 general malfunction, P0441 incorrect purge flow, P0446 vent control circuit) are among the most common check-engine codes on 3rd- and 4th-gen 4Runners. Toyota issued service bulletin EG013-03 covering these codes across 4Runner/Camry/Tacoma. The frequent culprit is a Vacuum Switching Valve (VSV) — especially the canister-closed-valve VSV near the charcoal canister mounted above the spare tire — which sticks when charcoal fines migrate into it. A loose/failed gas cap or a cracked canister can also trigger the codes.
Start cheap: verify the fuel cap seals and clicks. Then test the VSVs (there are typically three — two under the hood and one at the canister): apply 12V and listen for the click and check that airflow switches; a stuck/silent VSV is the failed part and is far cheaper than the whole canister. Replace the failed VSV or, if the charcoal canister is shedding/cracked, replace the canister. Use genuine Toyota EVAP parts to pass monitors reliably. Gas cap ~$15-40; VSV ~$30-120; full charcoal canister $150-500.
The exact parts — OEM, plus what owners actually use. Skip the internet hunt.
The cheap first check for P0440/P0446 — a cap that doesn't click/seal sets EVAP codes. Genuine Toyota tethered cap 77300-47010 is the current service part for 2003-2009 (4th gen) and supersedes the 3rd-gen 77300-33010/33030/33050/33051/33052 caps, so it back-fits the 1996-2002 4Runners as well. Veri
The primary culprit named in the issue — the canister VSV that sticks when charcoal fines migrate into it. parts.toyota.com lists 90910-12264 as 'Valve, Vacuum Switching (For Charcoal Canister),' fitment 2000-2002 4Runner 2.7L/3.4L (supersedes 90910-12198). Test by applying 12V and listening for the
Under-hood purge VSV that controls when stored vapors are drawn into the intake; a stuck purge VSV drives P0441 (incorrect purge flow). Toyota catalog: 25860-75160 'Valve Assy, Vacuum Switching No.2,' 1996-2000 4Runner 2.7L/3.4L (3rd gen). 4th-gen (2003-2009, 4.0L/4.7L) uses different assemblies (e.
Replace only if the canister is cracked or shedding charcoal (fines are what foul the VSVs). Toyota catalog PNs by era: 1996-2001 = 77740-35392; 2000-2002 = 77740-35482 (supersedes -35481); 2003-2005 = 77740-35490; 2004-2007 = 77740-35511 (supersedes -35500); 2006-2009 = 77740-35530. Listed PN is th
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On the 1996-2002 Toyota 4Runner 3.4L 5VZ-FE V6, the 5VZ-FE water pump is driven off, and buried behind, the timing belt. Its shaft seal wears with age and mileage and coolant begins seeping from the pump's weep hole — the designed early-warning drip before the bearing fails. Because accessing the pump requires the same teardown as a timing-belt job, owners search heavily for how to combine the two. Ignoring the weep can progress to bearing failure, coolant starvation, and (since the 5VZ is an interference engine) a snapped-belt catastrophe if the belt is also neglected.
Replace the water pump whenever the timing belt is serviced (Toyota interval ~90k miles), and vice-versa. Do the belt, tensioner, and idler pulleys at the same time — the labor is identical. Key parts: Aisin/Toyota water pump assembly 16100-69398-83; timing belt 13568-YZZ03 (Aisin), hydraulic tensioner and idler/tensioner bearings, thermostat 90916-03075, and new coolant. Complete OEM/Aisin timing + water-pump kits are widely available (~$150-250 in parts); shop labor typically brings it to $500-900.
The exact parts — OEM, plus what owners actually use. Skip the internet hunt.
Confirmed OEM/Aisin water pump for the 3.4L 5VZ-FE in 1996-2002 4Runner (also T100/Tacoma/Tundra). Aisin is the factory supplier; supersedes/interchanges with 16100-69395. Includes water-pump gasket. This is THE part the weep-hole leak requires; replace with the timing belt since access is identical
Confirmed OEM timing belt for 1996-2002 4Runner 3.4L 5VZ-FE (191 teeth). Toyota replacement interval ~90k mi / 72 mo. Drives the water pump, so it is always done in the same teardown.
Confirmed OEM hydraulic tensioner for the 5VZ-FE (1995-2004). Applies tension to the belt via the No.2 idler; comes with the release pin. Always replaced with the belt since it is buried in the same teardown.
Confirmed OEM 5VZ-FE timing idler bearing (paired with 13505-62070). Both idlers ride behind the belt and should be replaced together with the belt/tensioner.
Confirmed OEM 5VZ-FE second timing idler bearing. Distinct from 13503-62040; both are listed in the Aisin OE kit for 1995-2004 3.4L V6.
Confirmed OEM thermostat for 1996-2002 4Runner 3.4L 5VZ-FE (named in the FIX). Exposed once the coolant system is drained/pump is off — cheap insurance to replace during the job.
Confirmed OEM thermostat housing gasket for the 5VZ-FE (Toyota lists thermostat 90916-03075 + gasket 16325-62010 together). Required to reseal the thermostat.
Confirmed OEM front crankshaft (timing-cover) seal used on the 3.4L 5VZ-FE. Accessible only with the timing belt off, so it is a standard replace-while-in-there item to prevent a fresh belt getting oil-soaked.
Confirmed OEM front camshaft seal for the 5VZ-FE (supersedes 90311-38031/38034). Two are needed (both cylinder banks). Replaced during the timing-belt teardown for the same oil-contamination reason.
Toyota Red Long Life Coolant (HOAT, ethylene-glycol) is the correct era-appropriate coolant for a 1996-2002 3.4L (this generation used RED LLC, not the later pink SLLC). System capacity ~2.6 gal; mix 50/50 with distilled water. New coolant is required after the drain.
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On the 1996-2002 Toyota 4Runner 3.4L 5VZ-FE V6, on the 3rd-gen 4Runner's 3.4L 5VZ-FE V6, the two knock sensors sit in the engine valley beneath the upper and lower intake manifolds, and their sub-wiring harness bakes over time. The harness insulation becomes brittle and crumbles, opening the circuit and setting P0325 (knock sensor 1 circuit) and/or P0330 (knock sensor 2 circuit). The ECU then pulls timing, hurting fuel economy and power. It is a very high-demand repair topic because the fix is buried under the intake, and because the ECU is extremely sensitive to sensor signal quality.
Remove the upper and lower intake manifolds and replace BOTH knock sensors plus the knock-sensor sub-harness. Use OEM/Denso sensors only — aftermarket knock sensors very frequently fail to clear the code, forcing you to redo the whole labor-intensive job. Key parts: knock-sensor sub-harness Toyota 82219-34010; two Denso knock sensors (Denso 89615-series); new upper and lower intake manifold gaskets and a fresh coolant fill. Budget roughly $150-300 in genuine parts (harness + 2 sensors + gaskets), or ~$400-900 done at a shop given the intake teardown labor.
The exact parts — OEM, plus what owners actually use. Skip the internet hunt.
THE primary failure part named in the fix. Fits 5VZ-FE 3.4 V6 4Runner (1995/96-2002), plus T100/Tacoma/Tundra 1995-2004. The insulation bakes brittle in the valley and opens the circuit, setting P0325/P0330. Genuine runs ~$70-130; low-cost aftermarket harnesses exist (~$25-45) but reliability varies
Need TWO (5VZ-FE runs two identical flat/washer-type sensors in the valley). Price is per sensor. Matsushita/Denso genuine. Fits 4Runner 1991/92-2001/02, Tacoma/T100 3.4. USE OEM/Denso ONLY — aftermarket knock sensors frequently fail to clear P0325/P0330, forcing a full intake-teardown redo. Note: s
Required to reseal the upper intake plenum (air intake chamber) that must come off to reach the valley. Genuine Toyota 17176-62040 is packaged as a set of 2 (both plenum faces). Fits all 5VZ-FE 3.4 (1995-2004). Verified genuine PN.
Two needed (one per cylinder bank) to reseal the lower intake manifold to the heads after pulling it to access the knock sensors. Genuine 17177-62060 fits 5VZ-FE 3.4: 4Runner 1995-2002, T100 1994-98, Tacoma 1995-2004, Tundra 2000-04. Price is per gasket. Verified genuine PN on Toyota catalogs / Yota
Coolant is drained/disturbed pulling the intake, so a fresh fill is required. Genuine Toyota red LLC concentrate 00272-1LLAC (dilute 50/50); ~2 gallons covers the ~2.5-2.6 gal system capacity. Price per gallon. -01 suffix is just a packaging variant, same fluid. Verified on Toyota autoparts catalog.
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On the 1996-2009 Toyota 4Runner, 3rd- and 4th-gen 4Runners commonly develop power-steering whine and reddish ATF leaks with age. A whine is often not the pump itself but old fluid or a clogged filter screen in the bottom of the PS reservoir; leaks frequently originate at the union-bolt gaskets, high-pressure/return hoses, the pump shaft seal, or the steering rack. Heat cooks the pump seals, and some owners report rebuilding a pump twice from seal failure. Note: the 4Runner PS system uses ATF (Dexron), not conventional power-steering fluid — using the wrong fluid swells seals and causes failure.
For whine, first siphon the reservoir, clean the internal filter screen with brake cleaner, and refill with fresh Dexron II/III ATF — this alone often cures the noise. For leaks, pinpoint the source: replace the union-bolt sealing washers/gaskets for pump-fitting leaks, replace worn high-pressure/return hoses, or reseal/replace the pump if the shaft seal is leaking. Always refill with ATF, never generic PS fluid. Cleaning/flush is nearly free; hoses/gaskets $30-120; a replacement pump runs $120-350 in parts.
The exact parts — OEM, plus what owners actually use. Skip the internet hunt.
Confirmed genuine Toyota PN for 1996-2002 4Runner (3.4L 5VZ). Replace only if shaft seal/internal wear confirmed as leak/whine source after ruling out dirty fluid + clogged reservoir screen. OEM new ~$300-450; Cardone remans ~$120-200. Comes with reservoir. Refill with ATF (Dexron), never generic PS
Confirmed genuine Toyota PN for 2003-2009 4Runner (fits both 4.0 V6 and 4.7 V8). Do NOT use the 2010-2024 5th-gen pump 44310-60542 on this era. Aftermarket Cardone reman cross-refs listed are the commonly-cataloged fitment; verify by VIN before buying. Refill with ATF only.
Genuine Toyota pressure feed hose for 1999-2002 4Runner. Early 1996-1997 3.4L uses 44410-35400 instead (different PN — match by year). This is the pump-to-rack high-pressure line; a common age-related leak point. OEM ~$120-150; aftermarket ~$40-90.
Genuine Toyota low-pressure return/reservoir hose for 2003-2009 4Runner — the frequently-cited lower return-hose leak. Low-pressure line, so many owners also use bulk 3/8 in PS return hose + clamps as a cheap fix. Confirm exact PN by VIN as return-line PNs vary by engine.
Genuine Toyota banjo/union-bolt gasket for the PS pressure feed hose, cataloged 1994-2010 — this is the union-bolt sealing washer the fix calls out for pump-fitting leaks. Cheap; always replace both when the pressure line is disturbed. Buy 2.
Genuine Toyota pressure-port gasket for the feed hose; secondary sealing washer at the port side. Confirmed Toyota PN. Replace alongside 44327-30030 when resealing pump-fitting leaks.
Genuine Toyota PS reservoir for 2003-2009 4Runner (the tank whose bottom filter screen clogs). 3rd-gen 1998 4Runner uses 44360-20170 instead. Usually the screen is just cleaned with brake cleaner (free), but list this if the tank is cracked or the screen is non-serviceable. Match PN to year.
CRITICAL consumable: the 4Runner PS system uses ATF (Dexron II/III), NOT conventional power-steering fluid — wrong fluid swells seals and causes failure. Dexron VI is a backward-compatible replacement. ~1 qt for a flush/refill. No single OEM PN (any quality Dexron ATF qualifies), so OEM PN left empt
Consumable named in the fix — used to flush the clogged reservoir filter screen before refilling with fresh ATF (the near-free whine cure). Generic aerosol; no OEM PN.
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On the 1996-2002 Toyota 4Runner 3.4L 5VZ-FE V6, the 3.4L 5VZ-FE uses a rotary-solenoid Idle Air Control (IAC) valve on the throttle body to manage idle. Over high mileage the IAC passages and valve clog with carbon and oil deposits, producing erratic idle (hunting between ~700 and ~1200 RPM), high idle, or low idle that shakes and stalls — often stalling at stops or when the A/C compressor loads the engine. It's a very frequent, well-documented maintenance item for 5VZ-FE 4Runners/Tacomas and commonly sets P0505 (idle control system malfunction).
Remove and clean the IAC valve and throttle body bore/passages with throttle-body cleaner; inspect the connector and harness for corrosion or broken pins. Cleaning frequently restores normal idle, but a worn valve may need replacement — use an OEM/Denso IAC valve, as non-OEM units are a frequent cause of repeat P0505. Also rule out vacuum leaks, which mimic the same code. Cleaning is nearly free; an OEM IAC valve runs roughly $100-300, DIY-friendly.
The exact parts — OEM, plus what owners actually use. Skip the internet hunt.
Genuine Toyota/Denso IAC valve for 3.4L 5VZ-FE. Fits 4Runner 1996-2002 (and Tacoma/T100/Tundra 1995-2004) — era-correct for this issue's 1996-2002 range. Cleaning the existing valve is often enough; replace only if worn. STRONGLY use OEM/Denso — non-OEM units are a documented frequent cause of repea
Sealing gasket between the IAC valve and throttle body. Must be replaced whenever the IAC valve is removed for cleaning or replacement to prevent a vacuum leak (which itself mimics/causes P0505). Fits 3.4L 5VZ-FE 4Runner/T100/Tacoma/Tundra 1995-2004 — era-correct.
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SEATS:FRONT ASSEMBLY:SEAT HEATER/COOLER
Southeast Toyota Distributors, LLC (SET) is recalling certain model year 2010-2011 Prius and Corolla, 2009-2011 Venza, 2006-2010 Avalon, 2007-2010 FJ Cruiser, 2005-2011 Sienna and Sequoia, 2006-2011 Tacoma 4x2 and 4x4, Camry, Highlander, Tundra 4x2 and 4x4, and 2007-2011 Rav4 and 4Runner. The affected vehicles may experience compression of the seat cushion which may damage the seat heater wiring.
SEATS:FRONT ASSEMBLY:SEAT HEATER/COOLER
Southeast Toyota Distributors, LLC (SET) is recalling certain 2005-2011 4Runner, Highlander, Sequoia, and Sienna, 2005-2010 Avalon and Tundra, 2006-2008 Camry Solara, 2006-2010 Highlander hybrid, 2006-2011 Rav4 and Tacoma, 2007-2010 FJ Cruiser, 2007-2011 Camry hybrid, 2009-2010 Venza, 2010-2012 Prius, 1988-1990 and 2005-2010 Camry, and 1989 and 2009-2010 Corolla vehicles equipped with aftermarket accessory seat heaters with a copper strand heating element. The electrical wiring in the seat heaters may be damaged when the seat cushion is compressed.
AIR BAGS:FRONTAL:SENSOR/CONTROL MODULE-INACTIVE
Southeast Toyota Distributors, LLC (SET) is recalling certain models interspersed through model years 2009 through 2013 as follows: model year 2009-2012 Tacoma, 4Runner, Camry, Camry Hybrid, Prius, and RAV4; model year 2009-2010 Avalon, FJ Cruiser, and Highlander Hybrid; model year 2010-2013 model year Corolla, Sienna and Tundra; model year 2009-2013 Highlander and Venza; model year 2012 Prius V; and model year 2010-2012 Sequoia. During modification by SET to include accessories such as leather seat covers, seat heaters or headrest DVD systems, these vehicles may not have had the passenger seat occupant sensing system calibration tested. Without passing the calibration test, the occupant sensing system may not operate as designed.
VEHICLE SPEED CONTROL:ACCELERATOR PEDAL
TOYOTA IS RECALLING CERTAIN MODEL YEAR 2008 THROUGH 2011 LEXUS LX570, 2003 THROUGH 2009 TOYOTA 4RUNNER, AND 2006 THROUGH 2010 RAV4 VEHICLES. THE ACCELERATOR PEDAL CAN GET STUCK IN THE WIDE OPEN POSITION DUE TO ITS BEING TRAPPED BY AN UNSECURED OR INCOMPATIBLE DRIVER'S FLOOR MAT.
AIR BAGS:SIDE/WINDOW
Toyota Motor Engineering & Manufacturing (Toyota) is recalling certain model year 2003-2006 Toyota Land Cruiser and Lexus LX470, 2005-2006 Toyota Tundra and Sequoia, 2004-2006 Toyota 4Runner and Lexus GX470 vehicles equipped with side curtain-shield-air bags. The affected vehicles have an air bag control module that may be improperly programmed, causing the side curtain-shield-air bags to deploy inadvertently.
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According to Au7o's research across NHTSA recalls, manufacturer TSBs, and owner forum reports, the 1999-1999 Toyota 4Runner has 6 documented issues. The most frequently reported are: 3.4L 5VZ-FE Water Pump Weep Leak — Replace With Timing Belt Service, 3.4L 5VZ-FE Knock Sensor & Sub-Harness Failure (P0325/P0330) — Brittle Harness Under Intake, Power Steering Pump / System Leak & Whine — Reservoir Screen Clog and Seal Failure. None are rated critical, but regular maintenance is recommended.
The 1999-1999 Toyota 4Runner has 6 known issues compiled from NHTSA recalls, manufacturer TSBs, and owner forum reports. No issues are rated critical, suggesting generally good reliability. Regular maintenance following the manufacturer's schedule helps prevent many common problems.
Repair costs for known Toyota 4Runner issues range from $15 to $2,500, depending on the specific problem and whether you choose DIY or professional repair. Au7o provides step-by-step DIY maintenance guides that can help reduce repair costs.
The 5VZ-FE water pump is driven off, and buried behind, the timing belt. Its shaft seal wears with age and mileage and coolant begins seeping from the pump's weep hole — the designed early-warning drip before the bearing fails. Because accessing the pump requires the same teardow… Repairs typically run $150-$900. Severity: medium.
On the 3rd-gen 4Runner's 3.4L 5VZ-FE V6, the two knock sensors sit in the engine valley beneath the upper and lower intake manifolds, and their sub-wiring harness bakes over time. The harness insulation becomes brittle and crumbles, opening the circuit and setting P0325 (knock se… Repairs typically run $150-$900. Severity: medium.
3rd- and 4th-gen 4Runners commonly develop power-steering whine and reddish ATF leaks with age. A whine is often not the pump itself but old fluid or a clogged filter screen in the bottom of the PS reservoir; leaks frequently originate at the union-bolt gaskets, high-pressure/ret… Repairs typically run $20-$500. Severity: medium.
As 4Runners accumulate miles, the catalytic converter loses efficiency and the ECU sets P0420 (Bank 1) and/or P0430 (Bank 2) when the downstream O2 sensor starts to mirror the upstream sensor. On the 4th-gen 1GR-FE, the primary cats are integrated into the exhaust manifolds, whic… Repairs typically run $150-$2,500. Severity: medium.
The 3.4L 5VZ-FE uses a rotary-solenoid Idle Air Control (IAC) valve on the throttle body to manage idle. Over high mileage the IAC passages and valve clog with carbon and oil deposits, producing erratic idle (hunting between ~700 and ~1200 RPM), high idle, or low idle that shakes… Repairs typically run $20-$350. Severity: low.
EVAP faults (P0440 general malfunction, P0441 incorrect purge flow, P0446 vent control circuit) are among the most common check-engine codes on 3rd- and 4th-gen 4Runners. Toyota issued service bulletin EG013-03 covering these codes across 4Runner/Camry/Tacoma. The frequent culpri… Repairs typically run $15-$500. Severity: low.
Content on this page was compiled with AI assistance using NHTSA complaints, TSBs, owner reports, and public automotive data. While we strive for accuracy, this information may contain errors. Always verify repair procedures and specifications with your vehicle's service manual or a qualified mechanic.
