05–1027

DIAGNOSTICS – ELECTRONICALLY CONTOROLLED BRAKE SYSTEM 05IZI–01

DTC C1246/46 MALFUNCTION IN MASTER CYLINDER

PRESSURE SENSOR

DTC C1364/61 MALFUNCTION IN W/C PRESSURE SENSOR

CIRCUIT DESCRIPTION
The master cylinder pressure sensor and the wheel cylinder pressure sensor are built into the brake actuator,
and measure the master cylinder pressure and the wheel cylinder pressure send to the skid control ECU.
DTC No. Detailed Code DTC Detecting Condition Trouble Area
Sensor power source 1 (VMC1)
Brake actuator assy
C1246/46 191 voltage is less than 4.7 V or 5.3 V
Skid control ECU
or more for at least 0.05 sec.
Harness and connector
Ratio of master pressure sensor
output voltage 1 (PMC1) to sensor
Brake actuator assy
C1246/46 192 power source (VMC1) is less than
Skid control ECU
5% or 90.5% or more for at least
Harness and connector
0.05 sec.
Sensor power source 2 (VMC2)
Brake actuator assy
C1246/46 194 voltage is less than 4.7 V or 5.3 V
Skid control ECU
or more for at least 0.05 sec.
Harness and connector
Ratio of master pressure sensor
output voltage 2 (PMC2) to sen-
Brake actuator assy
C1246/46 195 sor power source (VMC2) is less
Skid control ECU
than 5% or 90.5% or more for at
Harness and connector
least 0.05 sec.
Master pressure sensor output
Brake actuator assy
C1246/46 197
voltage 1 (PMC1) is abnormal.
Skid control ECU
Master pressure sensor output
Brake actuator assy
C1246/46 198
voltage 2 (PMC2) is abnormal.
Skid control ECU

Brake actuator assy
Master pressure sensor output 1

Skid control ECU
C1246/46 199 (PMC1) is not approx. 0 Mpa when

Harness and connector
not braking.

Stop input signal

Brake actuator assy
Master pressure sensor output 2

Skid control ECU
C1246/46 200 (PMC2) is not approx. 0 Mpa when

Harness and connector
not braking.

Stop input signal

Brake actuator assy
PMC1 and PMC2 voltages are dif-
C1246/46 201
Skid control ECU
ferent when braking.

Harness and connector

Brake actuator assy
Master pressure sensor 1 data
C1246/46 202
Skid control ECU
(PMC1) is invalid.

Harness and connector

Brake actuator assy
Master pressure sensor 2 data
C1246/46 205
Skid control ECU
(PMC2) is invalid.

Harness and connector
Sensor power source 1 (VMC1)

Harness and connector
C1364/61 221 voltage is less than 4.7 V or 5.3 V

Skid control ECU
or more for at least 0.05 sec.
Raio of FR right sensor output
voltage (PFR) to sensor power
Brake actuator assy
C1364/61 222 source (VCM1) is less than 5% or
Skid control ECU
90.5% or more for at least 0.05
Harness and connector
sec.

2004 Prius – Preliminary Release (RM1075U)

Author: Date: 1191

05–1028
DIAGNOSTICS – ELECTRONICALLY CONTOROLLED BRAKE SYSTEM

DTC No. Detailed Code DTC Detecting Condition Trouble Area

FR right sensor output (PFR) is
not approx. 0 Mpa when not
braking.
Brake actuator assy
C1364/61 224
FR right sensor (PFR) zero point
Skid control ECU
malfunction.
Harness and connector

Open or short in FR right sensor
(PFR) circuit.
Ratio of FR right sensor output
voltage (PFR) to sensor power
Brake actuator assy
C1364/61 225 source (VCM1) is less than 90.5%
Skid control ECU
for at least 0.1 sec. when self–
Harness and connector
diagnosis signal is output.
Sensor power source 2 (VMC2)
Brake actuator assy
C1364/61 227 voltage is less than 4.7 V or 5.3 V
Skid control ECU
or more for at least 0.05 sec.
Harness and connector
Ratio of FR lefr sensor output volt-

Brake actuator assy
age (PFL) to sensor power source
C1364/61 228
Skid control ECU
(VCM2) is less than 5% or 90.5%

Harness and connector
or more for at least 0.05 sec.

FR left sensor (PFL) is not
approx. 0 Mpa when not braking.

Brake actuator assy

FR left sensor (PFL) zero point
C1364/61 230
Skid control ECU
malfunction

Harness and connector

Open or short in FR right sensor
(PFL) circuit.
Ratio of FR left sensor output volt-
age (PFL) to sensor power source
Brake actuator assy
C1364/61 231 (VCM2) is less than 90.5% for at
Skid control ECU
least 0.1 sec. when self–diagnosis
Harness and connector
signal is output.
Sensor power source 2 (VCM2)
Brake actuator assy
C1364/61 233 voltage is less than 4.7 V or 5.3 V
Skid control ECU
or more for at least 0.05 sec.
Harness and connector
Ratio of RR right sensor output
voltage (PRR) to sensor power
Brake actuator assy
C1364/61 234 source (VCM2) is less than 5% or
Skid control ECU
90.5% or more for at least 0.05
Harness and connector
sec.

RR right sensor output voltage
(PRR) is not approx. 0 Mpa when
not braking.
Brake actuator assy
C1364/61 236
RR right sensor (PRR) zero point
Skid control ECU
malfunction.
Harness and connector

Open or short in RR sensor
(PRR) circuit.
Ratio of RR right sensor output
voltage (PRR) to sensor power
Brake actuator assy
C1364/61 237 source (VCM2) is less than 90.5%
Skid control ECU
for at least 0.1 sec. when self–
Harness and connector
diagnosis signal is output.
Sensor power source (VMC1) volt-
Brake actuator assy
C1364/61 239 age is less than 4.7 V or 5.3 V or
Skid control ECU
more for at least 0.05 sec.
Harness and connector
Ratio of RR left sensor output volt-

Brake actuator assy
age (PRL) to sensor power source
C1364/61 240
Skid control ECU
(VCM1) is less than 5% or 90.5%

Harness and connector
or more for at least 0.05 sec.

2004 Prius – Preliminary Release (RM1075U)

Author: Date: 1192

 05–1029
DIAGNOSTICS – ELECTRONICALLY CONTOROLLED BRAKE SYSTEM

DTC No. Detailed Code DTC Detecting Condition Trouble Area

Voltage difference before and after

Brake actuator assy
changing the pull–up resistance in
C1364/61 226
Skid control ECU
the sensor signal input circuit is

Harness and connector
0.3 V or more (poor connection).
Voltage difference before and after

Brake actuator assy
changing the pull–up resistance in
C1364/61 232
Skid control ECU
the sensor signal input circuit is

Harness and connector
0.3 V or more (poor connection).
Voltage difference before and after

Brake actuator assy
changing the pull–up resistance in
C1364/61 238
Skid control ECU
the sensor signal input circuit is

Harness and connector
0.3 V or more (poor connection).

RR left sensor output (PRL) is
not approx. 0 Mpa when not
braking.
Brake actuator assy
C1364/61 242
RR left sensor (PRL) zero point
Skid control ECU
malfunction.
Harness and connector

Open or short in RR left sensor
(PRL) circuit.

Ratio of RR left sensor output
voltage (PRL) to sensor power
Brake actuator assy
C1364/61 243 source (VCM1) is less than
Skid control ECU
90.5% for at least 0.1 sec. when
Harness and connector
sel–diagnosis signal is output.
Voltage difference before and after

Brake actuator assy
changing the pull–up resistance in
C1364/61 244
Skid control ECU
the sensor signal input circuit is 03

Harness and connector
V or more (poor connection).

2004 Prius – Preliminary Release (RM1075U)

Author: Date: 1193

05–1030
DIAGNOSTICS – ELECTRONICALLY CONTOROLLED BRAKE SYSTEM

WIRING DIAGRAM

A2 Brake Actuator Skid Control ECU

18
G
PRL S7 PRL
36
23
Y
PFR S7 PFR
34
30
R
PMC1 S7 PMC1
38
21
W
PACC S7 PACC
46
31
B
PCK1 S7 PCK1
37
8
L
E1 S7 E
45
9
P
VCM1 S7 VCM1
35
29
G
E2 S10 E2
44
31
Y
PRR S10 PRR
41
23
R
PFL S10 PFL
39
27
W
PMC2 S10 PMC2
43
14
B
VCM2 S10 VCM2
40
21
L
PCK2 S10 PCK2
42

F47299

2004 Prius – Preliminary Release (RM1075U)

Author: Date: 1194

 05–1031
DIAGNOSTICS – ELECTRONICALLY CONTOROLLED BRAKE SYSTEM

INSPECTION PROCEDURE
1 CHECK HARNESS AND CONNECTOR

(a) Disconnect the skid control ECU connector and brake ac-
Skid Control ECU
tuator connector.
S7 S10 (b) Measure the resistance according to the value(s) in the
table below.
Standard:
VCM1 VCM2 Tester Connection Specified Condition
E S7–8 (E) – A2–45 (E1) Below 1 Ω

PRL S7–9 (VCM1) – A2–35 (VCM1) Below 1 Ω

PRR S7–18 (PRL) – A2–36 (PRL) Below 1 Ω

PMC1 PMC2
S7–21 (PACC) – A2–46 (PACC) Below 1 Ω
PFR PFL PCK2
PCK1 S7–23 (PFR) – A2–34 (PFR) Below 1 Ω
PACC E2
S7–30 (PMC1) – A2–38 (PMC1) Below 1 Ω
Brake Actuator Assy S7–31 (PCK1) – A2–37 (PCK1) Below 1 Ω
(harness side connector) A2 S10–14 (VCM2) – A2–40 (VCM2) Below 1 Ω
S10–21 (PCK2) – A2–42 (PCK2) Below 1 Ω
S10–23 (PFL) – A2–39 (PFL) Below 1 Ω
S10–27 (PMC2) – A2–43 (PMC2) Below 1 Ω
S10–29 (E2) – A2–44 (E2) Below 1 Ω
S10–31 (PRR) – A2–41 (PRR) Below 1 Ω
F47487
(c) Measure the resistance according to the value(s) in the
table below.
Standard:
Tester Connection Specified Condition
S7–8 (E) – Body ground 10 kΩ or higher
S7–9 (VCM1) – Body ground 10 kΩ or higher
S7–18 (PRL) – Body ground 10 kΩ or higher
S7–21 (PACC) – Body ground 10 kΩ or higher
S7–23 (PFR) – Body ground 10 kΩ or higher
S7–30 (PCM1) – Body ground 10 kΩ or higher
S7–31 (PCK1) – Body ground 10 kΩ or higher
S10–14 (VCM2) – Body ground 10 kΩ or higher
S10–21 (PCK2) – Body ground 10 kΩ or higher
S10–27 (PMC2) – Body ground 10 kΩ or higher
S10–29 (E2) – Body ground 10 kΩ or higher
S10–31 (PRR) – Body ground 10 kΩ or higher

NG REPAIR OR REPLACE HARNESS OR

CONNECTOR

OK

2004 Prius – Preliminary Release (RM1075U)

Author: Date: 1195

05–1032
DIAGNOSTICS – ELECTRONICALLY CONTOROLLED BRAKE SYSTEM

2 INSPECT SKID CONTROL ECU TERMINAL VOLTAGE

Skid Control ECU (a) Measure the voltage according to the value(s) in the table
VCM1 VCM2 below.
E
HINT:
Measure the voltage from behind the connector with the con-
nector connected to the skid control ECU.
Standard:
Tester Connection Condition Specified Condition
E2 S7–9 (VCM1) – Power switch ON
4.75 to 5.25 V
Body ground (READY)
F47485
S10–14 (VCM2) – Power switch ON
4.75 to 5.25 V
Body ground (READY)

(b) Measure the resistance according to the value(s) in the

table below.
Standard:
Tester Connection Specified Condition
S7–8 (E) – Body ground Below 1 Ω
S10–29 (E2) – Body ground Below 1 Ω

NG REPLACE SKID CONTROL ECU ASSY

(SEE PAGE 32–68)

OK

3 READ VALUE OF HAND–HELD TESTER

(a) Connect the hand–held tester to the DLC3.

(b) Select the DATA LIST mode on the hand–held tester.
Measurement Item /
Item Normal Condition
Range (Display)
Master cylinder pressure sensor 1 When brake pedal is released:
MAS CYL PRS 1
reading / min.: 0 V, max.: 5 V 0.3 to 0.9 V
Master cylinder pressure sensor 2 When brake pedal is released:
MAS CYL PRS 2
reading / min.: o V, max.: 5 V 0.3 to 0.9 V
(c) Check the output value of the master cylinder pressure sensor on the hand–held tester display.
OK:
When the pedal is depressed, displayed voltage on the hand–held tester increase.
NG REPLACE BRAKE ACTUATOR ASSY
(SEE PAGE 32–54)

OK

2004 Prius – Preliminary Release (RM1075U)

Author: Date: 1196

 05–1033
DIAGNOSTICS – ELECTRONICALLY CONTOROLLED BRAKE SYSTEM

4 READ VALUE OF HAND–HELD TESTER

(a) Connect the pedal effort gauge.

(b) Install the LSPV gauge (SST) and bleed air (see page 32–4).
SST 09709–29018
(c) Connect the hand–held tester to the DLC3.
(d) Select the DATA LIST mode on the hand–held tester.
Measurement Item /
Item Normal Condition
Range (Display)
Front Right pressure sensor / When brake pedal is released:
FR PRESS SENS
min.: 0 V, max.: 5 V 0.3 to 0.9 V
Front Left pressure sensor / When brake pedal is released:
FL PRESS SENS
min. 0 V, max.: 5 V 0.3 to 0.9 V
Rear Right pressure sensor / When brake pedal is released:
RR PRESS SENS
min.: 0 V, max.: 5 V 0.3 to 0.9 V
Rear Left pressure sensor / When brake pedal is released:
RL PRESS SENS
min. 0 V, max.: 5 V 0.3 to 0.9 V
(e) Check the output value of the wheel cylinder pressure sensor at each fluid pressure during the ECB
control.
Standard:
Fluid Pressure FR PRESS SENS FL PRESS SENS RR PRESS SENS RL PRESS SENS
MPa (kgf/cm2, psi) (DATA–LIST) (DATA–LIST) (DATA–LIST) (DATA–LIST)
1 (10.2, 145.0) 0.65 to 0.75 V 0.65 to 0.75 V 0.65 to 0.75 V 0.65 to 0.75 V
3 (30.6, 435.2) 1.05 to 1.2 V 1.05 to 1.2 V 1.05 to 1.2 V 1.05 to 1.2 V
7 (71.4, 1015.5) 1.8 to 2.05 V 1.8 to 2.05 V – –
10 (102.0, 1450.7) 2.4 to 2.7 V 2.4 to 2.7 V – –

NG REPLACE BRAKE ACTUATOR ASSY

(SEE PAGE 32–54)

OK

REPLACE SKID CONTROL ECU ASSY (SEE PAGE 32–68)

NOTICE:
When replacing the skid control ECU assy, perform initialization of linear solenoid valve and calibra-
tion (see page 05–958).

2004 Prius – Preliminary Release (RM1075U)

Author: Date: 1197