05–1045

DIAGNOSTICS – ELECTRONICALLY CONTOROLLED BRAKE SYSTEM 05IZL–01

DTC C1252/52 BRAKE BOOSTER PUMP MOTOR ON TIME

ABNORMALLY LONG

DTC C1253/53 BRAKE BOOSTER PUMP MOTOR CIRCUIT

CIRCUIT DESCRIPTION
The skid control ECU detects decreases in the accumulator pressure according to the data from the accumu-
lator pressure sensor, and then starts and stops the pump motor by operating the motor relay.
The skid control ECU usually drives the motor relay 1 for ECB control, and the motor relay 2 for ABS control.
If either is malfunctioning, the other substitutes.
DTC No. Detailed Code DTC Detecting Condition Trouble Area
Motor relay is ON for at least 5
C1252/52 130
Brake actuator assy
min.
Motor relay 1 coil (monitor) is en-
ABS MTR relay
ergized for at least 1 sec. when
ABS MTR2 relay
C1253/53 132
main relay 1 monitor (BS1) is 9.5
Harness and connector
V or more and motor relay 1 is off.
Brake actuator assy
Motor relay 1 coil (monitor) is not
ABS MTR relay
energized for at least 1 sec. when
ABS MTR2 relay
C1253/53 133
main relay 1 monitor (BS1) is 9.5
Harness and connector
V or more and motor relay 1 is on.
Brake actuator assy
MTT input is 3.5 V or less for at
ABS MTR relay
least 0.2 sec. when main relay 1
ABS MTR2 relay
C1253/53 134
monitor (BS1) is 9.5 V or more and
Harness and connector
motor relay 1 is on.
Brake actuator assy
Motor relay 2 coil (monitor) is en-
ABS MTR relay
ergized for at least 1 sec. when
ABS MTR2 relay
C1253/53 136
main relay 2 monitor (BS2) is 9.5
Harness and connector
V or more and motor relay 2 is off.
Brake actuator assy
Motor relay 2 coil (monitor) is not

ABS MTR relay
energized for at least 1 sec. (0.2

ABS MTR2 relay
C1253/53 137 sec. during initial check) when

Harness and connector
main rely 2 monitor (BS2) is 9.5 V

Brake actuator assy
or more and motor relay 2 is on.
MTT input is 3.5 V or less for at

ABS MTR relay
least 1 sec. (0.2 sec. during initial

ABS MTR2 relay
C1253/53 138 check) when main relay 1 monitor

Harness and connector
(BS1) is 9.5 V or more and motor

Brake actuator assy
relay 2 is on.

ABS MTR relay
MTT input is 3.5 V or more for at

ABS MTR2 relay
C1253/53 140 least 2 sec. when motor relay 1

Harness and connector
and 2 are off.

Brake actuator assy

2004 Prius – Preliminary Release (RM1075U)

Author: Date: 1209

05–1046
DIAGNOSTICS – ELECTRONICALLY CONTOROLLED BRAKE SYSTEM

WIRING DIAGRAM

A2 Brake Actuator Skid Control ECU

29
MTT 33 R
S7 MTT
11
GR
S7 MR1+
Engine Room R/B

ABS MTR Relay

25
3 3 S7 MR1
2 1
BM1 2 G
3 3
3 5
ABS MTR2 Relay
30
3 3 S10 MR2
2 1
BM2 1 R
3 3
3 5
Engine Room J/B 25
R
1 ABS–2 4 S10 MR2+
3M 3C L
1 2
ABS–1 3
B
3C
1 2 1
W
S7 GND
1
B B 2
BE1 W–B W
S8 GND2
GND1 31 W–B
1
GND 2 32 W–B W
S8 GND3
2
F15 W–B
S9 GND4
FL Block
1
W–B W–B
S9 GND5
1
MAIN 4
W–B
S10 GND6

Auxiliary
EF EE
Battery

F47849

2004 Prius – Preliminary Release (RM1075U)

Author: Date: 1210

 05–1047
DIAGNOSTICS – ELECTRONICALLY CONTOROLLED BRAKE SYSTEM

INSPECTION PROCEDURE
1 PERFORM ACTIVE TEST BY HAND–HELD TESTER(ABS MOTOR RELAY
OPERATION)

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

(b) Turn the power switch ON (READY).
(c) Select the ACTIVE TEST mode on the hand–held tester.
(d) Check the operation sound of the ABS motor individually when operating it with the hand–held tester.
Measurement Item /
Item Normal Condition
Range (Display)
Operation of solenoid
MOTOR RELAY 1 Turns MOTOR RELAY 1 ON / OFF
(clicking sound) can be heard
Operation of solenoid
MOTOR RELAY 2 Turns MOTOR RELAY 2 ON / OFF
(clicking sound) can be heard
OK:
The operation sound of the ABS motor should be heard.
NG Go to step 6

OK

2 INSPECT FUSE(ABS–1, ABS–2 FUSE)

Engine Room (a) Remove the ABS–1 and ABS–2 fuse from the engine
R/B room R/B
(b) Measure the resistance according to the value(s) in the
table below.
Standard:
ABS–1 ABS–1 Below 1 Ω (Continuity)
Fuse ABS–2 Below 1 Ω (Continuity)

ABS–2
Fuse

F47765 NG CHECK FOR SHORT IN ALL HARNESS AND

CONNECTOR CONNECTED TO FUSE AND
REPLACE FUSE

OK

2004 Prius – Preliminary Release (RM1075U)

Author: Date: 1211

05–1048
DIAGNOSTICS – ELECTRONICALLY CONTOROLLED BRAKE SYSTEM

3 INSPECT BRAKE ACTUATOR ASSY

Brake Actuator Assy (a) Disconnect the brake actuator assy connector.
(b) Measure the resistance according to the value(s) in the
BM1 BM2
table below.
Standard:
Tester Connection Specified Condition
1 (BM2) – 31 (GND1) Below 10 Ω
2 (BM1) – 31 (GND1) Below 10 Ω
MTT 1 (BM2) – 2 (BM1) Below 1 Ω
GND1
GND2 F47491
31 (GND1) – 32 (GND2) Below 1 Ω
1 (BM2) – 33 (MTT) About 33 Ω
2 (BM1) – 33 (MTT) About 33 Ω

NG REPLACE BRAKE ACTUATOR ASSY

OK

4 CHECK HARNESS AND CONNECTOR(SKID CONTROL ECU – BRAKE ACTUATOR

ASSY)

(a) Disconnect the skid control ECU connector and brake ac-
Skid Control ECU tuator assy connector.
(b) Measure the resistance according to the value(s) in the
S7 table below.
Standard:
Tester Connection Specified Condition
S7–29 (MTT) – A2–33 (MTT) Below 1 Ω
A2–31 (GND1) – Body ground Below 1 Ω
A2–32 (GND2) – Body ground Below 1 Ω
MTT

Brake Actuator Assy

A2
(harness side connector)

GND1 MTT
GND2 NG REPAIR OR REPLACE HARNESS OR
F47492 CONNECTOR

OK

2004 Prius – Preliminary Release (RM1075U)

Author: Date: 1212

 05–1049
DIAGNOSTICS – ELECTRONICALLY CONTOROLLED BRAKE SYSTEM

5 READ VALUE OF HAND–HELD TESTER

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

(b) Turn the power switch ON (READY).
(c) Select the DTA LIST mode on the hand–held tester.
Measurement Item /
Item Normal Condition
Range (Display)
Accumulator pressure sensor 1 / min.:
ACC PRESS SENS 1 Specified value: 3.2 to 4.0 V
0 V, max.: 5 V
(d) Depress the brake pedal 4 or 5 times to operate the pump motor, and check the output value on the
hand–held tester with the motor stopped (not braking).
OK:
Accumulator (ACC) pressure sensor voltage does not drop.
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).
6 INSPECT ABS MOTOR RELAY

(a) Remove the ABS motor relay and ABS motor relay 2.
(b) Measure the resistance according to the value(s) in the
table below.
Standard:
Tester Connection Connection Specified Resistance
10 kΩ or higher (No conti-
3–5 Always
nuity)
Apply B+ between termi-
3–5 Below 1 Ω
nal 1 and 2
B57491

NG REPLACE ABS MOTOR RELAY

OK

2004 Prius – Preliminary Release (RM1075U)

Author: Date: 1213

05–1050
DIAGNOSTICS – ELECTRONICALLY CONTOROLLED BRAKE SYSTEM

7 CHECK HARNESS AND CONNECTOR

Engine Room R/B (a) Remove the ABS motor relay and ABS motor relay 2.
ABS MTR Relay (b) Measure the voltage according to the value(s) in the table
(5)
below.
Standard:
Tester Connection Specified Condition
ABS Motor Relay (5) – Body ground 10 to 14 V
ABS Motor Relay 2 (5) – Body ground 10 to 14 V

ABS MTR
Relay 2
(5) F47688 NG REPAIR OR REPLACE HARNESS OR
CONNECTOR

OK

2004 Prius – Preliminary Release (RM1075U)

Author: Date: 1214

 05–1051
DIAGNOSTICS – ELECTRONICALLY CONTOROLLED BRAKE SYSTEM

8 CHECK HARNESS AND CONNECTOR(ENGINE ROOM R/B – BRAKE ACTUATOR)

(a) Disconnect the brake actuator assy connector.

Brake Actuator Assy
(b) Remove the ABS MTR Relay and ABS MTR Relay 2.
A2 (harness side connector)
(c) Measure the resistance according to the value(s) in the
table below.
Standard:
Tester Connection Specified Condition
A2–1 (BM2) – ABS MTR Relay 2 (3) Below 1 Ω
BM2 BM1
A2–2 (BM1) – ABS MTR Relay (3) Below 1 Ω

Engine Room R/B (d) Measure the resistance according to the value(s) in the
table below.
ABS Standard:
MTR Tester Connection Specified Condition
Relay (3) A2–1 (BM2) – Body ground 10 kΩ or higher
A2–2 (BM1) – Body ground 10 kΩ or higher

ABS MTR Relay 2 (3) F47493 NG REPAIR OR REPLACE HARNESS OR

CONNECTOR

OK

2004 Prius – Preliminary Release (RM1075U)

Author: Date: 1215

05–1052
DIAGNOSTICS – ELECTRONICALLY CONTOROLLED BRAKE SYSTEM

9 CHECK HARNESS AND CONNECTOR(ENGINE ROOM R/B – SKID CONTROL

ECU)

Skid Control ECU (a) Disconnect the skid control ECU connector.
(b) Remove the ABS MTR Relay and ABS MTR Relay 2.
S7 S10 (c) Measure the resistance according to the value(s) in the
table below.
Standard:
MR2+ Tester Connection Specified Condition
S7–11 (MR1+) – ABS MTR Relay (2) Below 1 Ω

MR1+ S7–25 (MR1) – ABS MTR Relay (1) Below 1 Ω

S10–25 (MR2+) – ABS MTR 2 Relay (2) Below 1 Ω
MR1 MR2
S10–30 (MR2) – ABS MTR 2 Relay (1) Below 1 Ω
Engine Room R/B
(d) Measure the resistance according to the value(s) in the
MR1 table below.
Standard:
MR1+ Tester Connection Specified Condition
S7–11 (MR1+) – Body ground 10 kΩ or higher
S7–25 (MR1) – Body ground 10 kΩ or higher
S10–25 (MR2+) – Body ground 10 kΩ or higher
S10–30 (MR2) – Body ground 10 kΩ or higher

MR2+

MR2 F47494 NG REPAIR OR REPLACE HARNESS OR

CONNECTOR

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: 1216