Toyota prius 3rd gen Occupant Detection ECU (W2)(W3)

Toyota Prius 3 ^rd Generation (XW30)

Occupant Detection ECU Assembly Wiring Guide: DIY Pinout Diagram

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What is:TheThe Occupant Detection ECU (Electronic Control Unit) is a small control computer that is part of a vehicle’s airbag system. It receives signals from the occupant detection sensors located in the seats to determine whether a seat is occupied and, if so, the size and weight of the occupant. This information helps the system decide whether to deploy the airbag and at what intensity during a collision, improving passenger safety and preventing unnecessary airbag deployment.

1. Introduction

The Toyota Prius 3rd generation Occupant Detection ECU is a safety control unit located under the passenger seat. It processes signals from weight sensors in the seat cushion to identify whether the seat is empty, holds a child, or an adult, and communicates with the airbag ECU to control passenger airbag deployment.

Occupant Detection ECU Assembly – Most Common in (XW30)

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• Components:
• SeatOccupant Detection ECU– the control unit that processes sensor signals.
• Seat weight (pressure) sensors – built into the passenger seat cushion to measure load.
• Seat harness and connectors – wiring linking sensors to the ECU.
• Airbag ECU (SRS control module – receives data from the Occupant Detection ECU and manages airbag deployment.
• Passenger airbag ON/OFF indicator light– shows airbag activation status to the driver.

2. Occupant Detection ECU Assembly Wiring Diagram & Pinout

A. Connector Location

• Occupant Detection ECU Position: Under the front passenger seat.
• Connector Type:
  • W2 (12 pin) gray housing
  • W3 (12 pin) black housing

B. Wiring Table

Occupant Detection ECU Assembly (W2) (W3)

W2 TERMINALS OF Occupant Detection ECU Assembly CONECTOR

Terminal No	Symbol (Pin Definition)	Wiring (Color Code) & Color	Electrical Paths
1	1	(G) Green	➔ W4 3 [Front In Weight Detection Sensor Sub–Assembly]
2	2	(LG) Light Green	➔ W6 3 [Front Out Weight Detection Sensor Sub–Assembly]
3	3	(W) White	➔ W1 3 [Rear In Weight Detection Sensor Sub–Assembly]
4	4	(BR) Brown	➔ W7 3 [Rear Out Weight Detection Sensor Sub–Assembly]
5	5	(GR) Gray	➔ W1 1 [Rear In Weight Detection Sensor Sub–Assembly]
6	6	(V) Violet	➔ W7 1 [Rear Out Weight Detection Sensor Sub–Assembly]
7	7	(P) Pink	➔ W4 2 [Front In Weight Detection Sensor Sub–Assembly]
8	8	(L) Blue	➔ W6 2 [Front Out Weight Detection Sensor Sub–Assembly]
9	9	(SB) Sky Blue	➔ W1 2 [Rear In Weight Detection Sensor Sub–Assembly]
10	10	(B) Black	➔ W7 2 [Rear Out Weight Detection Sensor Sub–Assembly]
11	11	(R) Red	➔ W4 1 [Front In Weight Detection Sensor Sub–Assembly]
12	12	(W) White	➔ W6 1 [Front Out Weight Detection Sensor Sub–Assembly]

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W3 TERMINALS OF Occupant Detection ECU Assembly CONECTOR

Terminal No	Symbol (Pin Definition)	Wiring (Color Code) & Color	Electrical Paths
1	1	(W) White	➳ SW1 5 ➳ LS1 59 ➔ 3A 1 ⇔ 3B 73 ➔ 2A 48 ⇔ 2C 18 ➔ 1 2 ➤ (BAT) 7.5A Blade Fuse [ECU–B]
2	2	(GR) Gray	➳ SW1 2 ➳ LS1 58 ➔ 3A 12 ⇔ 3A 48 ➔ L61 7 (SIL) [DLC3]
3	3	(W-B) White/Black	➳ SW1 3 ➔ S20 2 ⬌ S20 10 ➔ ▼ S1 (Ground Point)
4	4	(LG) Light Green	➳ SW1 4 ➔ S1 13 (FSR-) [Center Airbag Sensor Assembly]
5	5	(P) Pink	➔ W5 2 [Front Seat Inner Belt Assembly RH]
6	_	_
7	7	(B) Black	➳ SW1 6 ➳ LS1 60 ➔ 3A 9 ⇔ 3B 84 ➔ 2A 32 ➤ (IG) 10A Blade Fuse [IGN]
8	8	(L) Blue	➳ SW1 1 ➔ S1 12 (FSR+) [Center Airbag Sensor Assembly]
9	9	(G) Green	➔ W5 1 [Front Seat Inner Belt Assembly RH]
10	_	_
11	_	_
12	_	_

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