05–1088
DIAGNOSTICS – ELECTRONICALLY CONTOROLLED BRAKE SYSTEM 05IZU–01
DTC C1365/54 MALFUNCTION IN ACC PRESSURE
SENSOR
CIRCUIT DESCRIPTION
The accumulator (ACC) pressure sensor is built into the brake actuator.
The skid control ECU detects the accumulator pressure from the data sent from the accumulator pressure
sensor, and then runs and stops the pump motor by operating the motor relay.
DTCs may be output if the accumulator pressure drops due to frequent braking (this is not a malfunction).
DTC No. Detailed Code DTC Detecting Condition Trouble Area
Sensor power 1 (VCM1) voltage is Brake actuator assy (accumula-
C1365/54 211 4.7 V or less or 5.3 V or more for tor pressure sensor)
at least 0.05 sec. Skid control ECU
Ratio of accumulator pressure
sensor output voltage (PACC) to Brake actuator assy (accumula-
C1365/54 212 sensor power 1 (VCM1) voltage is tor pressure sensor)
5% or less or 90.5% or more for at Skid control ECU
least 0.05 sec.
Total wheel cylinder pressure sen-
sor exceeds 12 MPa after de-
Brake actuator assy (accumula-
pressing brake pedal, but accumu-
C1365/54 214 tor pressure sensor)
lator pressure sensor output volt-
Skid control ECU
age (PACC) changes less than 0.5
MPa for at least 0.5 sec.
Ratio of accumulator pressure
sensor output voltage (PACC) to Brake actuator assy (accumula-
C1365/54 215 sensor power 1 (VCM1) voltage is tor pressure sensor)
90.5% or less for at least 0.1 sec. Skid control ECU
during self–diagnosis.
Voltage difference is 0.3 V or more
Brake actuator assy (accumula-
before and after changing the pull
C1365/54 216 tor pressure sensor)
up resistance in sensor signal in-
Skid control ECU
put circuit (loose contact).
2004 Prius – Preliminary Release (RM1075U)
Author: Date: 1252
05–1089
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: 1253
05–1090
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.
(b) Measure the resistance according to the value(s) in the
S7 table below.
Standard:
Tester Connection Specified Condition
VCM1 S7–8 (E) – A2–45 (E1) Below 1 Ω
E S7–9 (VCM1) – A2–35 (VCM1) Below 1 Ω
S7–21 (PACC) – A2–46 (PACC) Below 1 Ω
PACC
S7–31 (PCK1) – A2–37 (PCK1) Below 1 Ω
PCK1
Brake Actuator Assy (c) Measure the resistance according to the value(s) in the
(harness side connector)
table below.
A2 PCK1
Standard:
Tester Connection Specified Condition
S7–8 (E) – Body ground 10 kΩ or higher
S7–9 (VCM1) – Body ground 10 kΩ or higher
S7–21 (PACC) – Body ground 10 kΩ or higher
VCM1 E1
S7–31 (PCK1) – Body ground 10 kΩ or higher
PACC
F47492
NG REPAIR OR REPLACE HARNESS OR
CONNECTOR
OK
2 INSPECT SKID CONTROL ECU TERMINAL VOLTAGE(VCM1 – GND)
Skid Control ECU (a) Measure the voltage according to the value(s) in the table
below.
VCM1 GND
HINT:
Measure the voltage from behind the connector with the con-
nector connected to the skid control ECU.
Standard:
Tester Connection Condition Specified Condition
S7
S7–9 (VCM1) – Power switch
4.75 to 5.25 V
F47485
S7–1 (GND) ON (READY)
NG REPLACE SKID CONTROL ECU ASSY
(SEE PAGE 32–54)
OK
2004 Prius – Preliminary Release (RM1075U)
Author: Date: 1254
05–1091
DIAGNOSTICS – ELECTRONICALLY CONTOROLLED BRAKE SYSTEM
3 INSPECT SKID CONTROL ECU TERMINAL VOLTAGE(PACC – GND)
Skid Control ECU (a) Check the auxiliary battery voltage.
Standard: 10 to 14 V
S7 GND
(b) Depress the brake pedal to operate the pump motor, and
then check that the pump motor stops.
(c) Measure the voltage according to the value(s) in the table
below.
Standard:
PACC
Tester Connection Specified Condition
F47485 S7–21 (PACC) – S7–1 (GND) 3.3 to 4.7 V
NOTICE:
Do not depress the brake until after the pump motor
stops and the voltage check is finished in order to
keep the accumulator pressure.
Check from behind the connector with the connector
connected to the skid control ECU.
Do not use a DATA LIST, as the sensor itself must be
checked.
NG REPLACE BRAKE ACTUATOR ASSY
(SEE PAGE 32–54)
OK
4 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 DATA 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 (no 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).
2004 Prius – Preliminary Release (RM1075U)
Author: Date: 1255
