TERMINALS OF ECU

Fig 1: Identifying Skid Control ECU Connector Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

ECU CONNECTOR TERMINALS DESCRIPTION CHART

Terminal No. (Symbol)

Terminal Description

1 (GND1)

Skid control ECU ground

3 (GL1)⁽¹⁾

Deceleration sensor input

4 (RL-)

Rear wheel speed LH (-) signal input

5 (RL+)

Rear wheel speed LH (+) signal input

6 (FR-)

Front wheel speed RH (-) signal input

7 (FR+)

Front wheel speed RH (+) signal input

12 (+BS)

Solenoid relay power supply

13 (GND2)

Pump motor ground

14 (CANL)

CAN communication line L

15 (GGND)⁽¹⁾

Deceleration sensor ground

16 (RR-)

Rear wheel speed RH (-) signal input

17 (RR+)

Rear wheel speed RH (+) signal input

18 (FL-)

Front wheel speed LH (-) signal input

19 (FL+)

Front wheel speed LH (+) signal input

22 (SP1)

Speed signal output for speedometer

24 (+BM)

Motor relay power supply

25 (CANH)

CAN communication line H

26 (VGS)⁽¹⁾

Deceleration sensor power supply output

28 (STP)

Stop light switch input

32 (TS)

Sensor check input

34 (IG1)

ECU power supply

⁽¹⁾

for 4WD

TERMINAL INSPECTION

Disconnect the connector and measure the voltage or resistance on the wire harness side.

Fig 2: Identifying A39 Skid Control ECU Connector Terminals

HINT:

Voltage cannot be measured with the connector connected to the skid control ECU as the connector is watertight.

Standard

A39 SKID CONTROL ECU CONNECTOR TERMINALS SPECIFIED CONDITIONS

Terminal No. (Symbol)	Wiring Color	Terminal Description	Condition	Specified Condition
A39-1 (GND1) - Body ground	W-B - Body ground	Skid control ECU ground	Always	Below 1 Ω
A39-12 (+BS) - Body ground	W - Body ground	Solenoid relay power supply	Always	11 to 14 V
A39-13 (GND2) - Body ground	W-B - Body ground	Pump motor ground	Always	Below 1 Ω
A39-24 (+BM) - Body ground	L - Body ground	Motor relay power supply	Always	11 to 14 V
A39-28 (STP) - Body ground	L-W - Body ground	Stop light switch input	Stop light switch ON → OFF (Brake pedal depressed → released)	8 to 14 V → Below 1.5 V
A39-34 (IG1) - Body ground	L-B - Body ground	ECU power supply	Ignition switch ON	11 to 14 V

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Terminals Of Ecu

Use the Manual With the Right Hardware

When to See a Mechanic