Oxygen Sensors for Toyota Sienna (1998-2000) 3.0L Upstream & Downstream

Direct-Fit Upstream & Downstream Oxygen Sensor Kit for 1998-2000 Toyota Sienna

What it Does: The Oxygen Sensor Kit replaces degraded factory heated exhaust gas sensors on the 1998-2000 Sienna to restore closed-loop air-fuel metering, eliminate P0130-P0161 trouble codes, and stabilize idle quality.

The Stock Toyota Sienna Sensor Contamination & Thermal Fatigue

Factory zirconia O2 sensors on the first-generation XL10 platform face extreme thermal cycling within the transverse exhaust manifolds. Over decades of operation, the internal ceramic electrolyte thins while combustion byproducts, silica, and unburnt hydrocarbons poison the porous platinum electrodes. On the 1MZ-FE V6, this degradation results in sluggish millivolt output switching, causing the engine control module (ECM) to run unnecessarily rich default fuel trims. The consequences are fouled spark plugs, premature catalytic converter heat distress, rough warm idle, and failed tailpipe emissions tests.

The Engineering Solution

Engineered to match factory response curves, this 2-piece sensor kit features high-grade planar ceramic sensing elements wrapped in double-layered 304 stainless steel protective heat shields. Laser-welded leak-tight bodies prevent ambient moisture ingress, while pre-treated high-temperature wiring harnesses and factory-keyed pin connectors resist terminal fretting and exhaust radiated heat. Integrated ceramic heating circuits ensure rapid warm-up to reach 600°F operating temperature within seconds, providing instantaneous closed-loop feedback, crisp stoichiometric transitions, and reduced emissions.

Technical Specifications

Compatibility

• 1998 Toyota Sienna CE, LE, XLE (3.0L V6 1MZ-FE)
• 1999 Toyota Sienna CE, LE, XLE (3.0L V6 1MZ-FE)
• 2000 Toyota Sienna CE, LE, XLE (3.0L V6 1MZ-FE)

Frequently Asked Questions

Does this fit the XL10 Sienna?
Yes, this is a direct fit for the 1998-2000 Toyota Sienna equipped with the 1MZ-FE engine.

Do these sensors require thread anti-seize prior to installation?
Apply a sparse coating of high-temperature conductive anti-seize to threads only if un-plated, keeping compound completely clear of the sensor tip openings.

The Toyota Longevity Standard

Preserve Japanese family-van dependability and highway fuel efficiency by maintaining strict air-fuel feedback integrity across every mile of heavy suburban hauling.