NTK Upstream Oxygen Sensors (1985-89 MR2)

NTK Upstream Oxygen Sensor

For 1985–1989 Toyota MR2 AW11.

Overview

This direct-fit NTK oxygen sensor replaces the upstream sensor used by the original fuel-control system. NTK is an established original-equipment oxygen-sensor manufacturer. Its zirconia sensing element measures residual oxygen in the exhaust so the engine computer can adjust the air-fuel mixture.

Three application-specific versions cover U.S.-market Toyota MR2 AW11: 1985–1987 4A-GE one-wire unheated, 1988–1989 4A-GE four-wire heated, and 1988–1989 4A-GZE Supercharged four-wire heated.

Key Features

• Narrowband zirconia sensing for the upstream fuel-feedback circuit
• Direct-fit terminated connector for each listed application
• Application-specific harness length and mounting arrangement to match the factory sensor configuration
• One-wire unheated and four-wire heated versions matched to the listed engine and year application

Vehicle Fitment

Toyota MR2 — AW11 / MK1

• 1985–1987: U.S.-Market / 4A-GE naturally aspirated; one-wire unheated upstream sensor
• 1988–1989: U.S.-Market / 4A-GE naturally aspirated; four-wire heated upstream sensor
• 1988–1989: U.S.-Market Supercharged / 4A-GZE; four-wire heated upstream sensor

Fitment Notes

• The 1988–1989 naturally aspirated and Supercharged sensors are different configurations. Select the option that matches the original 4A-GE or 4A-GZE application.
• The four-wire sensors are not conversions for the 1985–1987 one-wire electrical circuit.
• Engine swaps, harness conversions and altered exhaust interfaces require separate component matching; original chassis year alone does not establish fitment.

Product Specifications

Brand: NTK
Product Type: Upstream Oxygen Sensor
Position: Upstream / Pre-Catalyst
Sensor Type: Narrowband Zirconia
Sensor-Body Hex: 22 mm
1985–1987 4A-GE Harness Length: 500 mm
1985–1987 4A-GE Wiring: 1 wire / 1 terminal
1985–1987 4A-GE Connector: Circular female housing with one male blade terminal
1985–1987 4A-GE Mount: Preassembled two-fastener flange
1988–1989 4A-GE Harness Length: 505 mm
1988–1989 4A-GE Wiring: 4 wires / 4 terminals
1988–1989 4A-GE Connector: Square female housing with four male blade terminals
1988–1989 4A-GE Mount: M18 × 1.5 threaded sensor with separate two-hole flange adapter
1988–1989 4A-GZE Harness Length: 375 mm / 14.75 in.
1988–1989 4A-GZE Wiring: 4 wires / 4 terminals
1988–1989 4A-GZE Connector: Square female housing with four male blade terminals
1988–1989 4A-GZE Mount: Flange
1988–1989 4A-GZE Thread Size: M18 × 1.5

Which Oxygen Sensor Should You Buy?

The comparison below concerns the listed AW11 applications.

NTK — Best for a Trusted, Factory-Style Replacement

Choose NTK if you want a factory-style, direct-fit replacement from an established original-equipment oxygen-sensor manufacturer. Match the original wiring and sensor configuration; brand choice does not replace correct application matching.

DENSO OE Upstream Oxygen Sensor — Best for Factory-Style Restoration

Choose DENSO if you want a direct-fit replacement from an established Toyota original-equipment supplier for your MR2 restoration. Match the engine and original sensor configuration; this is a brand preference, not a proven reliability advantage over NTK.

Our Recommendation: Match your MR2's model year, engine, original wiring, and sensor configuration first. Then choose the correctly matched NTK or DENSO sensor based on availability, price, and brand preference. Neither brand has a demonstrated reliability advantage across these AW11 applications.

Available Configurations

1985–1987 | One-Wire Unheated

• (1) One-wire unheated upstream oxygen sensor for the listed AW11 4A-GE application

1988–1989 | Four-Wire Heated

• (1) Four-wire heated upstream oxygen sensor for 4A-GE

1988–1989 | 4A-GZE Supercharged | Four-Wire Heated

• (1) Four-wire heated upstream oxygen sensor for 4A-GZE

All configurations include (1) new oxygen-sensor flange gasket.