IS300 Drive-By-wire setup

This comprehensive guide covers nearly everything you need to convert your Lexus IS300 to a modern Drive-By-Wire throttle system. Whether you're using a G35/350Z pedal, Subaru BRZ/FR-S pedal, or a high-performance Bosch electronic throttle body with a Haltech ECU, this walkthrough provides detailed steps, wiring diagrams, fitment tips, and Haltech configuration advice.

G35 Accelerator Pedal Conversion for IS300

This should be one of the most popular and is (to my knowledge) the most cost-effective way to add Drive-By-Wire to your IS300 if you have engine management. The G35/350Z pedal assembly is a direct bolt-in with minor modifications and pairs excellently with standalone ECUs like Haltech.

Key Advantages: Direct bolt-in to the IS300 firewall, inexpensive replacement sensors (~$20 OEM), and reliable performance.

Disadvantages: Requires bending the pedal arm forward ~30 degrees and cannot be used with the OEM IS300 ECU.

G35 Pedal Wiring (APPS Pinout)

From the video at moment in video where wiring is discussed:

• Pins 1 and 3: Sensor Ground (connect to ECU sensor ground, NOT chassis ground)
• Pins 4 and 6: 5V Supply (from Haltech ECU)
• Pin 2: APS2 (Sub pedal sensor signal)
• Pin 5: APS1 (Main pedal sensor signal)

APPS1 and APPS2 can be swapped — the Haltech will determine polarity during calibration.

Pedal Fitment & Modification Steps

From the video at moment in video where modification is discussed:

Step 1: Bend the G35 pedal arm forward approximately 30 degrees for proper ergonomics.

Step 2: Source two 1.5 inch M6x1.0 bolts for mounting (it's easier to mount if one M6x1.0 stud/nut is used in place of one of the bolts. Stud should be 2 inches long).

Step 4: Remove the IS300 pedal pad using a punch tool on the retaining pin.

Steps 5-8 (Pedal Pad Transfer): Grind off the 90-degree tip on the G35 pedal arm, grind excess material for fitment, secure the IS300 pad temporarily with coat hanger wire or thick copper wire in a U-shape, then epoxy or JB Weld it permanently in place.

Pro Tip: If you can weld, skip steps 4-8 entirely — cut both arms and weld the IS300 lower pad section onto the G35 upper arm.

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FR-S / BRZ DBW Pedal Alternative

The Subaru BRZ / Toyota FR-S pedal offers excellent ergonomics that match the IS300 brake and clutch pedal feel.

Advantages: Factory pedal pad styling matches IS300 perfectly and parts are widely available used on eBay.

Disadvantages: Requires a custom firewall mount, I wouldn't rely on a 3d printed part to hold an accelerator on my car as this can be disastrous. Another disadvantage is the sensor and pedal are a single expensive assembly compared to the APPS on the G35 which is ~$20 new, and the complete G35 pedal and APPS can be bought on ebay for less than $50.

FR-S / BRZ APPS Pinout (from HPAcademy)

• Pins 1 and 4: 5V from ECU
• Pins 2 and 5: Sensor Ground from ECU
• Pin 3: DBW - APP2
• Pin 6: DBW - APP1

Note: This pinout may be similar to later IS250/IS350 models (verify before use). APPS1/APPS2 from the Haltech engine management can be wired to either APP1 or APP2 prior to Haltech calibration but should not be switched after calibration.

Custom Mount & 3D Printed Adapter

Download STL ZIP File Here (For IS250 06/07 bracket — may require minor modification for BRZ/FR-S).

This 3d print file I found on STLfinder.com. It's for the IS250 06/07, but the bracket looks similar to the BRZ/FR-S mount points, so it may work or need some slight modification to fit a BRZ/FR-S pedal.

Bosch Drive-By-Wire Throttle Body Installation & Wiring

Bosch DBW throttle bodies are renowned for reliability in Porsche as well as other manufacturers and are a popular choice for high-horsepower builds.

Bosch DBW Pinout (Most Models Except 52mm)

• Pin 4: Motor +
• Pin 1: Motor -
• Pin 2: Sensor Ground
• Pin 3: 5V Supply
• Pin 6: TPS 1 Signal
• Pin 5: TPS 2 Signal

TPS1 and TPS2 can be swapped — Haltech auto-detects during calibration. Always verify with your specific throttle body datasheet.

Recommended Bosch Throttle Body Sizes & Purchase Links

• 82mm (0 280 750 473 / 101 / 780) — Ideal for high power: Buy on Amazon
• 74mm (0 280 750 474): Buy on Amazon
• 68mm (0 280 750 156) — Popular for custom motorsport: Buy on Amazon
• 54mm (0 280 750 150) — Not ideal for higher HP output: Buy on Amazon
• Note: Regarding TB diameter on a DBW application, the throttle curve can be adjusted post-calibration, meaning you can install a massive throttle body on a small engine and still retain driveability. Compared to a cable throttle setup with a large throttle body where the opening cannot be precisely controlled. Your large throttle DBW throttle body can be configured to open very gradually so it feels like a small throttle body, but has the advantage of large airflow and HP when necessary. It's also used by the haltech ECU as an idle air control valve, so the IACV would not be required when purchasing a DBW throttle body.

Browse Outsider Garage Bosch DBW Adapters & Flanges

Visit Haltech Official Website for compatible ECU options.

Haltech ECU Configuration & Calibration

Proper Haltech setup is critical for safe and responsive DBW operation. Refer to your specific Haltech model documentation and the official guide here for real-world calibration steps.

Additional helpful videos from the LegitRaceCraft IS300 Playlist:

• Adding Extra Fuses to IS300 Fuse Box
• Wiring a Standalone ECU into IS300 (with associated article)

For detailed DBW tuning theory, check resources from High Performance Academy (HPAcademy).

Safety Warnings & Recommendations

Recommended Resources:

• 2JZGarage IS300 Wiring Diagrams (Purchase official EWD for your year)
• Haltech support documentation for your specific ECU model

This guide is part of the migration from HournineRacecraft to LegitRaceCraft.com. For more IS300 builds and technical content, subscribe to the LegitRaceCraft YouTube channel.