DENSO Oxygen / Lambda Sensor – Pre Cat / Upstream • DOX-1435

Suitable for Mazda MX-5 Mk1 / NA 1.6 and 1.8 petrol applications, subject to the engine and production-period restrictions listed below. This is the upstream / pre-catalyst regulating oxygen sensor.

DENSO DOX-1435 is a Direct Fit heated oxygen / lambda sensor for selected Mazda MX-5 Mk1 / NA applications. It is supplied with the correct vehicle-specific connector and wiring arrangement, allowing direct replacement of the corresponding original sensor without splicing a universal sensor into the vehicle wiring loom.

The sensor is installed before the catalytic converter and operates as the regulating lambda sensor. It measures the oxygen content of the exhaust gases and provides feedback to the engine-management system so the ECU can adjust the air-fuel mixture.

Product Specifications

• Brand: DENSO
• Product range: Direct Fit
• Product type: Oxygen / lambda sensor
• Sensor type: Switching-type oxygen sensor
• Sensor design: Heated, finger / thimble-type sensor
• Sensor function: Regulating sensor
• Installation position: Upstream / pre-catalyst
• DENSO part number: DOX-1435
• DENSO universal equivalent: DOX-0109
• Thread size: M18 x 1.5
• Cable length: 670 mm
• Number of pins: 4
• Connector: Direct-fit vehicle connector
• Thread: Pre-greased
• Net weight: Approx. 108 g
• GTIN / EAN: 8717613025826
• Quantity required per vehicle at this position: 1
• Quantity supplied: 1 sensor

Important Fitment Note

DENSO lists DOX-1435 for the MX-5 Mk1 / NA 1.6 and 1.8, but the application varies according to engine version and production period.

• 1.6 115 PS / B64F and B6ZE applications: approximately May 1990 to January 1994
• 1.6 90 PS / 8AN1 applications: approximately January 1995 to April 1998
• 1.8 130-131 PS / BPF1 and related BP applications: approximately 1993 to April 1998

Because of the production changes within the Mk1 / NA range, do not select the sensor solely from the model year or engine capacity. Matching the existing connector and original sensor reference is particularly useful around changeover periods.

DOX-1435 is the upstream / pre-catalyst regulating sensor and must not be confused with any downstream / post-catalyst sensor fitted to the vehicle.

Typical Reasons for Replacement

An oxygen sensor may require replacement because of age-related deterioration, heater-circuit failure, contamination, damaged wiring or connector problems. A faulty regulating sensor can contribute to an engine-management warning light, incorrect mixture control, poor running or increased fuel consumption, although these symptoms can have other causes and should be properly diagnosed before replacing components.

Fitment Advice

Confirm that the sensor being replaced is the upstream / pre-catalyst sensor before removal. Compare the electrical connector, cable arrangement and original part number where necessary, particularly on vehicles close to an application change point.

For imported, modified or previously repaired cars, matching the part number or component style on the part being replaced is recommended.

Other Items to Consider

• Downstream / post-catalyst sensor where separately fitted and required
• Exhaust manifold and exhaust gaskets
• Exhaust-system fasteners
• Ignition components where poor running is being investigated
• Routine engine service components where appropriate

Useful Tools / Consumables

• Suitable oxygen / lambda sensor socket
• Ratchet and extension as required
• Torque wrench
• Penetrating fluid where appropriate for seized exhaust threads

Difficulty Guide

DIY Difficulty: Moderate. The sensor is threaded into the exhaust system and may become difficult to remove after prolonged exposure to heat and corrosion. Correct sensor identification and careful handling of the electrical connector are important.

Why DENSO?

DENSO is a long-established Japanese automotive component manufacturer with extensive experience in engine-management and emissions-control technology. Its Direct Fit lambda sensors are application-specific replacements supplied with the appropriate connector and wiring arrangement, providing a straightforward alternative to universal sensors that require wiring modification.

What's in the Box?

• 1 x DENSO DOX-1435 Direct Fit oxygen / lambda sensor

Installation Notes

Allow the exhaust system to cool before starting work. Disconnect the electrical connector before removing the existing sensor and avoid twisting or damaging the wiring during installation.

The sensor is supplied with a pre-treated thread. Avoid contaminating the sensing element and install using the appropriate tightening procedure.