Terminals Of Ecu

CHECK BATTERY VOLTAGE
1. Measure the battery voltage.
  Voltage: 10 to 14 V

SKID CONTROL ECU ASSEMBLY INSPECTION

Measure the voltage between each terminal or between each terminal and the body ground.
Connect the intelligent tester 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 the 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 Connector Terminals Skid Control ECU

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

HINT:

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

SKID CONTROL ECU

ECU TERMINAL VOLTAGE RESISTANCE SPECIFICATION CHART

Symbols (Terminal No.)	Wiring Color	Terminal Description	Condition	Specified Condition
GND1 (S38-1) - Body ground	W-B - Body ground	Skid control ECU ground	Always	Below 1 Ω
R1+ (S38-2) - Body ground	L-Y - Body ground	Main relay power 1	IG switch on	9.1 to 13.6 V
BS1 (S38-3) - Body ground	L - Body ground	Battery source 1	IG switch ON Approx. 1.5 sec. after turning IG switch ON	8.8 to 14 V
SMC1 (S38-4) - Body ground	V-W - Body ground	Master cut solenoid 1 output	IG switch ON Brake pedal depressed approx. 1.5 sec. after turning IG switch ON	Below 1.5 V
CTY+ (S38-5) - Body ground	W-R - Body ground	Courtesy power input	Driver door open → close	Approx. 5 sec. 8 to 16 V → Below 1 V
FRA- (S38-6) - Body ground	LG-B - Body ground	FR solenoid (-) output	IG switch ON Approx. 1.5 sec. after turning IG switch ON	Below 1.5 Ω
FRA+ (S38-7) - Body ground	LG - Body ground	FR solenoid (+) output	IG switch ON Brake pedal depressed approx. 1.5 sec. after turning IG switch ON	Pulse generation (see d waveform 1)
E (S38-8) - Body ground	W - Body ground	Pressure sensor ground	IG switch OFF	Below 1 Ω
VCM (S38-9) - Body ground	B - Body ground	Pressure sensor power	IG switch ON	4.75 to 5.25 V
MR1 (S38-11) - Body ground	Y-R - Body ground	Motor relay power 1	IG switch ON Approx. 1.5 sec. after turning IG switch ON	8.8 to 14 V
R3+ (S38-12) - Body ground	L-R - Body ground	Main relay output 1	IG switch ON Approx. 1.5 sec. or more after turning IG switch ON	Below 1 V
SS (S38-13) - Body ground	GR - Body ground	Stroke simulator cut	IG switch ON Brake pedal depressed	Below 1.5 V
RLA+ (S38-15) - Body ground	L - Body ground	RL solenoid (+) output	IG switch ON Brake pedal depressed approx. 1.5 sec. after turning IG switch ON	Pulse generation (see d waveform 1)
RLR+ (S38-16) - Body ground	GR - Body ground	RL solenoid (+) output	IG switch ON Brake pedal depressed approx. 1.5 sec. after turning IG switch ON	Pulse generation (see d waveform 1)
FRR+ (S38-17) - Body ground	P - Body ground	FR solenoid (+) output	IG switch ON After approx. 1.5 sec, brake pedal depressed → released	Pulse generation (see e waveform 2)
PRL (S38-18) - Body ground	W - Body ground	RL pressure sensor input	IG switch ON Brake pedal released	0.3 to 0.8 V
SG1 (S38-20) - Body ground	LG - Body ground	Pressure sensor shield ground 1	IG switch OFF	Below 1 Ω
PAC1 (S38-21) - Body ground	Y - Body ground	Accumulator pressure sensor input	IG switch ON After pump motor operates and stops by pedal operation	3.3 to 4.7 V
FR- (S38-22) - Body ground	O - Body ground	FR sensor (-) input	IG switch OFF	Below 1 Ω
PFR (S38-23) - Body ground	L - Body ground	FR pressure sensor input	IG switch ON Brake pedal released	0.3 to 0.8 V
R1- (S38-25) - Body ground	L-Y - Body ground	Motor relay output 1	IG switch ON Pump motor is operating	Below 1.5 V
RLR- (S38-26) - Body ground	GR-R - Body ground	RL solenoid (-) output	IG switch ON Approx. 1.5 sec. after turning IG switch ON	Below 1.5 V
RLA- (S38-27) - Body ground	Y - Body ground	RL solenoid (-) output	IG switch ON Approx. 1.5 sec. after turning IG switch ON	Below 1.5 V
MTT (S38-29) - Body ground	O - Body ground	Motor test input	IG switch ON Pump motor is operating	3.5 V or higher
PMC1 (S38-30) - Body ground	G - Body ground	Master pressure sensor input 1	IG switch ON Brake pedal released	0.3 to 0.8 V
PCK1 (S38-31) - Body ground	BR-Body ground	Pressure sensor check output 1	IG switch ON Approx. 1.5 sec. after turning IG switch ON	4.75 to 5.25 V
FR+ (S38-32) - Body ground	W - Body ground	FR sensor (+) input	Vehicle speed input	Pulse generation (see f waveform 3)
FRR- (S38-34) - Body ground	P-B - Body ground	FR solenoid (-) output	IG switch ON Approx. 1.5 sec. after turning IG switch ON	Below 1.5 V
GND3 (S39-1) - Body ground	W-B - Body ground	Skid control ECU ground	Always	Below 1 Ω
GND2 (S39-2) - Body ground	W-B - Body ground	Skid control ECU ground	Always	Below 1 Ω
+BI1 (S39-3) - Body ground	L - Body ground	Main relay power input 1	IG switch OFF	10 to 14 V
WFSE (S39-4) - Body ground	GR - Body ground	Mode control signal input	IG switch ON	9.1 to 13.6 V
+BO1 (S39-5) - Body ground	Y - Body ground	Main relay power output 1	IG switch ON	8.8 to 14 V
IG1 (S39-7) - Body ground	Y - Body ground	IG1 power	IG switch ON	10 to 14 V
RSS (S39-10) - Body ground	BR-Body ground	Speed sensor shield ground	IG switch OFF	Below 1 Ω
BZ (S39-12) - Body ground	O - Body ground	Warning buzzer output	IG switch ON Buzzer is operating	Below 1 V
STP (S39-14) - Body ground	B - Body ground	Stop light switch signal input	IG switch ON Brake pedal depressed → released	10 to 12 V → Below 1.5 V
CANL (S39-18) - Body ground	W - Body ground	CAN communication (Send and receive-)	Check DTC using intelligent tester	CAN communication's DTC is not output
CANH (S39-19) - Body ground	B - Body ground	CAN communication (Send and receive+)	Check DTC using intelligent tester	CAN communication's DTC is not output
FAIL (S39-20) - Body ground	B-R - Body ground	Capacitor communication (Receive)	IG switch ON Approx. 1.5 sec. after turning IG switch ON	Pulse generation (see h waveform 5)
SP1 (S39-22) - Body ground	BR-Body ground	Speedometer output	Vehicle speed input	Pulse generation (see g waveform 4)
RLO (S39-25) - Body ground	P - Body ground	RL speed signal output	Vehicle speed output	Pulse generation (see j waveform 7)
RL- (S39-27) - Body ground	G - Body ground	RL sensor (-) input	IG switch OFF	Below 1 Ω
ENA (S39-30) - Body ground	G-R - Body ground	Capacitor communication (Send)	IG switch ON Approx. 1.5 sec. after turning IG switch ON	Pulse generation (see i waveform 6)
TS (S39-32) - Body ground	GR - Body ground	Sensor diagnosis check input	IG switch ON	Below 1.5 V → 9.1 to 13.6 V
VBZ (S39-33) - Body ground	G - Body ground	Warning buzzer power	IG switch ON	9.1 to 13.6 V
RL+ (S39-35) - Body ground	R - Body ground	RL sensor (+) input	Vehicle speed input	Pulse generation (see f waveform 3)
GND5 (S40-1) - Body ground	W-B - Body ground	Skid control ECU ground	Always	Below 1 Ω
GND4 (S40-2) - Body ground	W-B - Body ground	Skid control ECU ground	Always	Below 1 Ω
+BO2 (S40-4) - Body ground	L- Body ground	Main relay power output 2	IG switch ON	8.8 to 14 V
+BI2 (S40-5) - Body ground	L-B - Body ground	Main relay power input 2	IG switch OFF	10 to 14 V
VCSK (S40-6) - Body ground	W - Body ground	Stroke sensor power	IG switch ON	3.75 to 4.95 V
SGSK (S40-7) - Body ground	Shielded - Body ground	Stroke sensor shield ground	IG switch OFF	Below 1 Ω
SKG (S40-8) - Body ground	R - Body ground	Stroke sensor power	IG switch OFF	Below 1 Ω
PKB (S40-14) - Body ground	LG - Body ground	Parking brake signal input	Parking brake applied → released	Below 1.5 V → 9.1 to 13.6 V
SKS (S40-21) - Body ground	G - Body ground	Stroke sensor signal input 1	IG switch ON Brake pedal released	0.46 to 1.35 V
SKS2 (S40-22) - Body ground	B - Body ground	Stroke sensor signal input 2	IG switch ON Brake pedal released	2.56 to 4.35 V
RR- (S40-23) - Body ground	R - Body ground	RR sensor (-) input	IG switch OFF	Below 1 Ω
EXI (S40-24) - Body ground	GR - Body ground	Cruise relay ON signal input	Cruise control brake OFF → ON	Below 1 Ω → 10 to 14 V
RR+ (S40-31) - Body ground	G - Body ground	RR sensor (+) input	Vehicle speed input	Pulse generation (see f waveform 3)
RRO (S40-33) - Body ground	O - Body ground	RR speed signal output	Vehicle speed output	Pulse generation (see j waveform 7)
FLA+ (S41-1) - Body ground	G-Y - Body ground	FL solenoid (+) output	IG switch ON Brake pedal depressed approx. 1.5 sec. after turning IG switch ON	Pulse generation (see d waveform 1)
FLA- (S41-2) - Body ground	V - Body ground	FL solenoid (-) output	IG switch ON Approx. 1.5 sec. after turning IG switch ON	Below 1.5 V
SMC2 (S41-3) - Body ground	V - Body ground	Master cut solenoid 2 output	IG switch ON Brake pedal depressed approx. 1.5 sec. after turning IG switch ON	Below 1.5 V
GND6 (S41-4) - Body ground	W-B - Body ground	Skid control ECU ground	Always	Below 1 Ω
IG2 (S41-5) - Body ground	W - Body ground	IG2 power	IG switch ON	10 to 14 V
LBL S41-6) - Body ground	B - Body ground	Brake fluid level switch input	Reservoir level switch OFF → ON	4 to 4.65 V → Below 1.5 V
BS2 (S41-7) - Body ground	G - Body ground	Battery source 2	IG switch ON Approx. 1.5 sec. after turning IG switch ON	8.8 to 14 V
FLR+ (S41-8) - Body ground	L - Body ground	FL solenoid (+) output	IG switch ON After approx. 1.5 sec, brake pedal depressed → released	Pulse generation (see e waveform 2)
RRA- (S41-9) - Body ground	Y-R - Body ground	RR solenoid (-) output	IG switch ON Approx. 1.5 sec. after turning IG switch ON	Below 1.5 V
CR(S41-11)- Body ground	G - Body ground	Cruise relay output	Cruise control brake OFF → ON	Below 1 V → 10 to 14 V
SG2 (S41-12) - Body ground	Shielded - Body ground	Pressure sensor shield ground 2	IG switch OFF	Below 1 Ω
FSS (S41-13) - Body ground	LG - Body ground	Speed sensor shield ground	IG switch OFF	Below 1 Ω
VCM2 (S41-14) - Body ground	BR - Body ground	Pressure sensor power 2	IG switch ON	4.75 to 5.25 V
R4+ (S41-15) - Body ground	B-R - Body ground	Main relay output 2	IG switch ON Approx. 1.5 sec. after turning IG switch ON	Below 1 V
R2+ (S41-17) - Body ground	G-Y - Body ground	Main relay power 2	IG switch ON	9.1 to 13.6 V
RRR- (S41-18) - Body ground	G-R - Body ground	RR solenoid (-) output	IG switch ON Approx. 1.5 sec. after turning IG switch ON	Below 1.5 V
RRA+ (S41-19) - Body ground	Y-G - Body ground	RR solenoid (+) output	IG switch ON Brake pedal depressed approx. 1.5 sec. after turning IG switch ON	Pulse generation (see d waveform 1)
RRR+ (S41-20) - Body ground	G-O - Body ground	RR solenoid (+) output	IG switch ON Brake pedal depressed approx. 1.5 sec. after turning IG switch ON	Pulse generation (see d waveform 1)
PCK2 (S41-21) - Body ground	G - Body ground	Pressure sensor check output 2	IG switch ON	4.75 to 5.25 V
FL- (S41-22) - Body ground	R - Body ground	FL sensor (-) input	IG switch OFF	Below 1 Ω
PFL (S41-23) - Body ground	R - Body ground	FL pressure sensor input	IG switch ON Brake pedal released	0.3 to 0.8 V
MR2 (S41-25) - Body ground	Y-B - Body ground	Motor relay power 2	IG switch ON Approx. 1.5 sec. after turning IG switch ON	8.8 to Below 14 V
FLR- (S41-26) - Body ground	L-W - Body ground	FL solenoid (-) output	IG switch ON Approx. 1.5 sec. after turning IG switch ON	Below 1.5 V
PMC2 (S41-27) - Body ground	L - Body ground	Master pressure sensor input 2	IG switch ON Brake pedal released	0.3 to 0.8 V
FL+ (S41-28) - Body ground	G - Body ground	FL sensor (+) input	Vehicle speed input	Pulse generation (see f waveform 3)
E2 (S41-29) - Body ground	Y - Body ground	Pressure sensor ground 2	IG switch OFF	Below 1 Ω
R2- (S41-30) - Body ground	L-R - Body ground	Motor relay output 2	IG switch ON Pump motor is operating	Below 1.5 V
PRR (S41-31) - Body ground	W - Body ground	RR pressure sensor input	IG switch ON Brake pedal released	0.3 to 0.8 V

Waveform 1
NOTE: Normal waveform is output only when BS 1 and 2 voltages are normal (10 to 14 V).

HINT:
- While driving at approximately 12 mph (20 km/h).
- 5 V/DIV, 200 ms/DIV.
- Brake pedal depressed.
Fig 2: Waveform Graph 1
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Waveform 2
NOTE: Normal waveform is output only when BS 1 and 2 voltages are normal (10 to 14 V).

HINT:
- While driving at approximately 12 mph (20 km/h).
- 5 V/DIV, 200 ms/DIV.
- Brake pedal depressed → released
Fig 3: Waveform Graph 2
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Waveform 3
NOTE: As the vehicle speed (tire rotating speed) becomes faster, the cycle becomes shorter and the output voltage larger.

HINT:
- 1 V/DIV, 2 ms/DIV.
- While driving at approximately 18 mph (30 km/h).
Fig 4: Waveform Graph 3
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Waveform 4
NOTE: As the vehicle speed (tire rotating speed) becomes faster, the cycle becomes shorter.

HINT:
- 5 V/DIV, 50 ms/DIV.
- While driving at approximately 12 mph (20 km/h).
Fig 5: Waveform Graph 4
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Waveform 5
HINT:
- 5 V/DIV, 200 ms/DIV.
- IG switch ON
Fig 6: Waveform Graph 5
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Waveform 6
HINT:
- 5 V/DIV, 100 ms/DIV.
- IG switch ON
Fig 7: Waveform Graph 6
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Waveform 7
NOTE: As the vehicle speed (tire rotating speed) becomes faster, the cycle becomes shorter.

HINT:
- 1 V/DIV, 2 ms/DIV.
- While driving at approximately 12 mph (20 km/h).
Fig 8: Waveform Graph 7
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.