Denso 3499 Spark Plug

Denso Iridium Long Life Spark Plug 3499

Denso 3499 is an Iridium Long Life spark plug built for OE-level performance, durability, and emissions control. It is a direct-fit ignition component for select Toyota, Lexus, and Scion applications, including Corolla, Prius, CT200h, and C-HR models.

Key Features

• Iridium center electrode tip for stable ignition performance
• Platinum chip ground electrode tip design for long service life
• 5000 ohm resistance for controlled secondary ignition output
• Copper center electrode core and nickel ground electrode core
• Flat seat design with 12.00 mm thread diameter and 26.50 mm reach
• Pre-gapped to 1.1 mm for OE-style installation
• Manufacturer heat range 16

Iridium Long Life Design

The Denso Iridium Long Life line is engineered for drivers who want OE-style ignition consistency and extended service intervals. This spark plug uses an iridium center electrode tip with a platinum chip ground electrode design to support reliable spark delivery in everyday driving conditions. Denso 3499 is specified for a range of Toyota Corolla and Prius applications, along with Lexus CT200h and select Scion models.

This part cross-references Denso Auto Parts SC16HR11 and Toyota 90919-01275 for the same application.

Vehicle Fitment

• Fits 2018-2022 Toyota C-HR, N/A; OE; Spark Plug - Iridium Long Life
• Fits 2012-2019 Toyota Corolla, N/A; Iridium Long Life
• Fits 2017-2018 Toyota Corolla iM, N/A; Iridium Long Life
• Fits 2018 Toyota Prius V, N/A; OE; Spark Plug - Iridium Long Life
• Fits 2012-2017 Lexus CT200h, N/A; Iridium Long Life
• Fits 2012-2017 Toyota Prius V, N/A; Iridium Long Life
• Fits 2016 Scion iM, N/A; Iridium Long Life
• Fits 2012-2015 Scion iQ, N/A; Iridium Long Life
• Fits 2012-2015 Toyota Prius, N/A; Iridium Long Life
• Fits 2012-2015 Toyota Prius Plug-In, N/A; Iridium Long Life
• Fits 2012-2014 Scion xD, N/A; Iridium Long Life
• Fits 2012-2013 Toyota Matrix, N/A; Iridium Long Life

Common Issues This Part Addresses

• Hard starting caused by worn spark plug electrodes
• Rough idle from inconsistent spark delivery
• Misfire conditions related to aged ignition components
• Reduced fuel economy from degraded combustion efficiency
• Emissions concerns tied to weak ignition performance

Installation Notes and Quality

Verify thread diameter, reach, seat type, and heat range against the original plug before installation. The pre-gap size is 1.1 mm, so confirm the gap specification matches the vehicle application before fitting. Use proper torque procedures and inspect ignition coils, boots, and threads during service. Denso manufactures this spark plug to OE performance, durability, and emissions standards for the listed Toyota, Lexus, and Scion applications.