Terminals Of Ecu

CHECK AUXILIARY BATTERY VOLTAGE
1. Check the auxiliary battery voltage.
Standard voltage:

11 to 14 V

SKID CONTROL ECU INSPECTION

Measure the voltage between each terminal or between each terminal and body ground.
Connect Techstream to the DLC3, and check the communication condition with the skid control ECU.

Using an oscilloscope, check that the pulse generates between each terminal or between each terminal and body ground.

NOTE:

Inspection should be performed from the back of the connector with the connector connected to the skid control ECU.
The voltage between the terminals of the brake actuator assembly may become 0 V due to the fail safe function when the brake control warning light comes on (malfunctioning).

Fig 1: Identifying Skid Control ECU Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

Inspect the ECU from the wire harness side while the connector is connected.

SKID CONTROL ECU TERMINALS SPECIFIED CONDITION

Symbols (Terminal No.)	Wiring Color	Terminal Description	Condition	Specified Condition
GND1 (A73-1) - Body ground	W-B - Body ground	Skid control ECU ground 1	Always	Below 1 Ω
R1+ (A73-2) - Body ground	B - Body ground	Main relay power 1	Power switch on (IG)	9.1 to 13.6 V
BS1 (A73-3) - Body ground	W - Body ground	Battery source 1	Approx. 1.5 seconds after turning power switch on (IG)	8.8 to 14 V
SMC1 (A73-4) - Body ground	W-B - Body ground	Master cut solenoid 1 output	Brake pedal depressed approx. 1.5 seconds after turning power switch on(IG)	Below 1.5 V
BCTY+ (A73-5) - Body ground	LG - Body ground	Courtesy power input	Driver door open → close	Approx. 5 sec. 8 to 16 V → Below 1 V
SLAFR- (A73-6) - Body ground	R - Body ground	Front addition solenoid (-) RH output	Approx. 1.5 seconds after turning power switch on (IG)	Below 1.5 V
SLAFR+ (A73-7) - Body ground	B - Body ground	Front addition solenoid (+) RH output	Brake pedal depressed approx. 1.5 seconds after turning power switch on (IG)	Pulse generation (See waveform d)
E (A73-8) - Body ground	R - Body ground	Pressure sensor ground	Power switch off	Below 1 Ω
VCM1 (A73-9) - Body ground	G - Body ground	Pressure sensor power	Power switch on (IG)	4.75 to 5.25 V
MR1+ (A73-11) - Body ground	B - Body ground	Motor relay power 1	Approx. 1.5 seconds after turning power switch on (IG)	8.8 to 14 V
R3+ (A73-12) - Body ground	W-B - Body ground	Main relay output 1	Approx. 1.5 seconds after turning power switch on (IG)	Below 1 V
SCSS (A73-13) - Body ground	P - Body ground	Stroke simulator cut solenoid output	Brake pedal depressed approx. 1.5 seconds after turning power switch on (IG)	Below 1.5 V
SLARL+ (A73-15) - Body ground	G - Body ground	Rear addition solenoid (+) LH output	Brake pedal depressed approx. 1.5 seconds after turning power switch on (IG)	Pulse generation (See waveform d)
SLRRL+ (A73-16) - Body ground	L - Body ground	Rear reduction solenoid (+) LH output	Brake pedal depressed approx. 1.5 seconds after turning power switch on (IG)	Pulse generation (See waveform d)
SLRFR+ (A73-17) - Body ground	L - Body ground	Front reduction solenoid (+) RH output	Power switch on (IG), after approx. 1.5 seconds brake pedal depressed → released	Pulse generation (See waveform e)
PRL (A73-18) - Body ground	G - Body ground	Rear pressure sensor LH input	Power switch on (IG), brake pedal released	0.3 to 0.8 V
SG1 (A73-20) - Body ground	O - Body ground	Pressure sensor shield ground 1	Power switch off	Below 1 Ω
PACC (A73-21) - Body ground	R - Body ground	Accumulator pressure sensor input	Power switch on (IG), after pump motor operates and stops by pedal operation	3.3 to 4.7 V
FR- (A73-22) - Body ground	G - Body ground	Front sensor (-) RH input	Power switch off	Below 1 Ω
PFR (A73-23) - Body ground	Y - Body ground	Front pressure sensor RH input	Power switch on (IG), brake pedal released	0.3 to 0.8 V
MR1 (A73-25) - Body ground	LG - Body ground	Motor relay output 1	Power switch on (IG), pump motor is operating	Below 1.5 V
SLRRL- (A73-26) - Body ground	B - Body ground	Rear reduction solenoid (-) LH output	Approx. 1.5 seconds after turning power switch on (IG)	Below 1.5 V
SLARL- (A73-27) - Body ground	R - Body ground	Rear addition solenoid (-) LH output	Approx. 1.5 seconds after turning power switch on (IG)	Below 1.5 V
MTT (A73-29) - Body ground	W - Body ground	Motor test input	Power switch on (IG), pump motor is operating	3.5 V or higher
PMC1 (A73-30) - Body ground	B - Body ground	Master pressure sensor input 1	Power switch on (IG), brake pedal released	0.3 to 0.8 V
PCK1 (A73-31) - Body ground	W - Body ground	Pressure sensor check output 1	Approx. 1.5 seconds after turning power switch on (IG)	4.75 to 5.25 V
FR+ (A73-32) - Body ground	R - Body ground	Front sensor (+) RH input	Vehicle speed input	Pulse generation (See waveform f)
SLRFR- (A73-34) - Body ground	LG-Body ground	Front reduction solenoid (-) RH output	Approx. 1.5 seconds after turning power switch on (IG)	Below 1.5 V
GND3 (A74-1) - Body ground	W-B - Body ground	Skid control ECU ground 3	Always	Below 1 Ω
GND2 (A74-2) - Body ground	W-B - Body ground	Skid control ECU ground 2	Always	Below 1 Ω
+BI1 (A74-3) - Body ground	R - Body ground	Main relay power input 1	Power switch off	10 to 14 V
+BO1 (A74-5) - Body ground	L - Body ground	Main relay power output 1	Power switch on (IG)	8.8 to 14 V
IG1 (A74-7) - Body ground	B - Body ground	IG1 power	Power switch on (IG)	10 to 14 V
BZ (A74-12) - Body ground	Y - Body ground	Skid control buzzer output	Power switch on (IG), buzzer is operating	Below 1 V
STP (A74-14) - Body ground	P - Body ground	Stop light switch signal input	Brake pedal depressed → released	8 to 14 V → Below 1.5 V
CANL (A74-18) - Body ground	W - Body ground	CAN communication (Send and receive-)	Check DTC using Techstream	CAN communication's DTC is not output
CANH (A74-19) - Body ground	B - Body ground	CAN communication (Send and receive+)	Check DTC using Techstream	CAN communication's DTC is not output
FAIL (A74-20) - Body ground	P - Body ground	Capacitor communication (Receive)	Approx. 1.5 seconds after turning power switch on (IG)	Pulse generation (See waveform h)
SP1 (A74-22) - Body ground	L - Body ground	Speedometer output	Vehicle speed input	Pulse generation (See waveform g)
RL- (A74-27) - Body ground	L - Body ground	Rear sensor (-) LH input	Power switch off	Below 1 Ω
ENA (A74-30) - Body ground	O - Body ground	Capacitor communication (Send)	Approx. 1.5 seconds after turning power switch on (IG)	Pulse generation (See waveform i)
TS (A74-32) - Body ground	G - Body ground	Sensor diagnosis check input	Power switch on (IG), connect terminals TS and CG of the DLC3 → disconnect	Below 1.5 V → 9.1 to 13.6 V
VBZ (A74-33) - Body ground	B - Body ground	Skid control buzzer power	Power switch on (IG)	9.1 to 13.6 V
RL+ (A74-35) - Body ground	R - Body ground	Rear sensor (+) LH input	Vehicle speed input	Pulse generation (See waveform f)
GND5 (A75-1) - Body ground	B - Body ground	Skid control ECU ground 5	Always	Below 1 Ω
GND4 (A75-2) - Body ground	W-B - Body ground	Skid control ECU ground 4	Always	Below 1 Ω
+BO2 (A75-4) - Body ground	R- Body ground	Main relay power output 2	Power switch on (IG)	8.8 to 14 V
+BI2 (A75-5) - Body ground	W - Body ground	Main relay power input 2	Power switch off	10 to 14 V
VCSK (A75-6) - Body ground	G - Body ground	Stroke sensor power	Power switch on (IG)	3.75 to 4.95 V
SSK (A75-7) - Body ground	BR - Body ground	Stroke sensor shield ground	Power switch off	Below 1 Ω
SKG (A75-8) - Body ground	R - Body ground	Stroke sensor ground	Power switch off	Below 1 Ω
SKS1 (A75-21) - Body ground	W - Body ground	Stroke sensor signal input 1	Power switch on (IG), brake pedal released	0.46 to 1.35 V
SKS2 (A75-22) - Body ground	B - Body ground	Stroke sensor signal input 2	Power switch on (IG), brake pedal released	2.56 to 4.35 V
RR- (A75-23) - Body ground	R - Body ground	Rear sensor (-) RH input	Power switch off	Below 1 Ω
RR+ (A75-31) - Body ground	G - Body ground	Rear sensor (+) RH input	Vehicle speed input	Pulse generation (See waveform f)
SLAFL+ (A76-1) - Body ground	L - Body ground	Front addition solenoid (+) LH output	Brake pedal depressed approx. 1.5 seconds after turning power switch on (IG)	Pulse generation (See waveform f)
SLAFL- (A76-2) - Body ground	B - Body ground	Front addition solenoid (-) LH output	Approx. 1.5 seconds after turning power switch on (IG)	Below 1.5 V
SMC2 (A76-3) - Body ground	LG-Body ground	Master cut solenoid 2 output	Brake pedal depressed approx. 1.5 seconds after turning power switch on (IG)	Below 1.5 V
GND6 (A76-4) - Body ground	BR - Body ground	Skid control ECU ground 6	Always	Below 1 Ω
IG2 (A76-5) - Body ground	GR - Body ground	IG2 power	Power switch on (IG)	10 to 14 V
LBL (A76-6) - Body ground	LG - Body ground	Brake fluid level warning switch input	Brake fluid level warning switch OFF → ON	4 to 8V → Below 1.5 V
BS2 (A76-7) - Body ground	G - Body ground	Battery source 2	Approx. 1.5 seconds after turning power switch on (IG)	8.8 to 14 V
SLRFL+ (A76-8) - Body ground	B - Body ground	Front reduction solenoid (+) LH output	Power switch on (IG), after approx. 1.5 seconds, brake pedal depressed → released	Pulse generation (See waveform e)
SLARR- (A76-9) - Body ground	B - Body ground	Rear addition solenoid (-) RH output	Approx. 1.5 seconds after turning power switch on (IG)	Below 1.5 V
SG2 (A76-12) - Body ground	BR - Body ground	Pressure sensor shield ground 2	Power switch off	Below 1 Ω
VCM2 (A76-14) - Body ground	BR-Body ground	Pressure sensor power 2	Power switch on (IG)	4.75 to 5.25 V
R4+ (A76-15) - Body ground	W - Body ground	Main relay output 2	Approx. 1.5 seconds after turning power switch on (IG)	Below 1 V
R2+ (A76-17) - Body ground	G - Body ground	Main relay power 2	Power switch on (IG)	9.1 to 13.6 V
SLRRR- (A76-18) - Body ground	G - Body ground	Rear reduction solenoid (-) RH output	Approx. 1.5 seconds after turning power switch on (IG)	Below 1.5 V
SLARR+ (A76-19) - Body ground	Y - Body ground	Rear addition solenoid (+) RH output	Brake pedal depressed approx. 1.5 seconds after turning power switch on (IG)	Pulse generation (See waveform d)
SLRRR+ (A76-20) - Body ground	R - Body ground	Rear reduction solenoid (+) RH output	Brake pedal depressed approx. 1.5 seconds after turning power switch on (IG)	Pulse generation (See waveform d)
PCK2 (A76-21) - Body ground	L - Body ground	Pressure sensor check output 2	Power switch on (IG)	4.75 to 5.25 V
FL- (A76-22) - Body ground	V - Body ground	Front sensor (-) LH input	Power switch off	Below 1 Ω
PFL (A76-23) - Body ground	R - Body ground	Front pressure sensor LH input	Power switch on (IG), brake pedal released	0.3 to 0.8 V
MR2+ (A76-25) - Body ground	Y - Body ground	Motor relay power 2	Approx. 1.5 seconds after turning power switch on (IG)	8.8 to 14 V
SLRFL- (A76-26) - Body ground	R - Body ground	Front reduction solenoid (-) LH output	Approx. 1.5 seconds after turning power switch on (IG)	Below 1.5 V
PMC2 (A76-27) - Body ground	W - Body ground	Master pressure sensor input 2	Power switch on (IG), brake pedal released	0.3 to 0.8 V
FL+ (A76-28) - Body ground	LG-Body ground	Front sensor (+) LH input	Vehicle speed input	Pulse generation (See waveform f)
E2 (A76-29) - Body ground	G - Body ground	Pressure sensor ground 2	Power switch off	Below 1 Ω
MR2 (A76-30) - Body ground	O - Body ground	Motor relay output 2	Power switch on (IG), pump motor is operating	Below 1.5 V
PRR (A76-31) - Body ground	Y - Body ground	Rear pressure sensor RH input	Power switch on (IG), brake pedal released	0.3 to 0.8 V

Waveform 1 (Reference): Using an oscilloscope:

WAVEFORM REFERENCE

Item	Condition
Tool setting	5 V/DIV., 200 ms./DIV.
Vehicle condition	While driving at approximately 20 km/h (12 mph) Brake pedal depressed

Fig 2: Waveform Graph (Waveform 1)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

Normal waveform is output only when BS1 and BS2 voltages are normal (10 to 14 V).

Waveform 2 (Reference): Using an oscilloscope:

WAVEFORM REFERENCE

Item	Condition
Tool setting	5 V/DIV., 200ms./DIV.
Vehicle condition	While driving at approximately 20 km/h (12 mph) Brake pedal depressed → released

Fig 3: Waveform Graph (Waveform 2)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

Normal waveform is output only when BS1 and BS2 voltages are normal (10 to 14 V).

Waveform 3 (Reference): Using an oscilloscope:

WAVEFORM REFERENCE

Item	Condition
Tool setting	1 V/DIV., 2 ms./DIV.
Vehicle condition	While driving at approximately 30 km/h (18 mph)

Fig 4: Waveform Graph (Waveform 3)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

As the vehicle speed (tire rotating speed) becomes faster, the cycle becomes shorter and the output voltage larger.

Waveform 4 (Reference): Using an oscilloscope:

WAVEFORM REFERENCE

Item	Condition
Tool setting	5 V/DIV., 50 ms./DIV.
Vehicle condition	While driving at approximately 20 km/h (12 mph)

Fig 5: Waveform Graph (Waveform 4)

HINT:

As the vehicle speed (tire rotating speed) becomes faster, the cycle becomes shorter.

Waveform 5 (Reference): Using an oscilloscope:

WAVEFORM REFERENCE

Item	Condition
Tool setting	5 V/DIV., 200 ms./DIV.
Vehicle condition	Turn the power switch on (IG)

Fig 6: Waveform Graph (Waveform 5)

Waveform 6 (Reference): Using an oscilloscope:

WAVEFORM REFERENCE

Item	Condition
Tool setting	2 V/DIV., 100ms./DIV.
Vehicle condition	Turn the power switch on (IG)

Fig 7: Waveform Graph (Waveform 6)