BRAKE CONTROL – VEHICLE STABILITY CONTROL SYSTEM BC–107
DTC C1246/46 Master Cylinder Pressure Sensor Malfunction
Master Cylinder Pressure Sensor Output Mal-
DTC C1281/81
function (Test Mode DTC)
DESCRIPTION
BC
The master cylinder pressure sensor is connected to the skid control ECU in the master cylinder solenoid.
Master Cylinder Solenoid (Skid Control ECU with Actuator)
Master Cylinder
Pressure Sensor
Skid Control ECU
From Battery VM/C1
IG1 VC
(VCM)
From PM/C1
STP VOUT
Stop Light Switch (PMC)
To Body Ground GND M/C1 GND GND
VM/C1 (VCM): Master Cylinder Pressure Sensor Power Supply Output
PM/C1 (PMC ): Master Cylinder Pressure Sensor Signal Input
M/C1 GND: Master Cylinder Pressure Sensor Ground
C124773E01
BC–108 BRAKE CONTROL – VEHICLE STABILITY CONTROL SYSTEM
DTC No. DTC Detecting Conditions Trouble Areas
When any of following conditions detected:
1. Both of following conditions continue for at least 30
seconds.
• Vehicle speed more than 4 mph (7 km/h).
• PM/C1 terminal voltage does not change by more
than 0.005 V once it exceeds 0.86 V.
BC 2. PM/C1 terminal receives noise at least 7 times within
5 seconds.
3. Both of following conditions continue for at least 5
seconds. • Hydraulic brake booster (master cylinder pressure
• Stop switch OFF. sensor)
C1246/46
• PM/C1 terminal voltage more than 0.86 V or less • Master cylinder solenoid (skid control ECU)
than 0.3 V. • Stop light switch circuit
4. Both of following conditions continue for at least 1.2
seconds.
• IG1 terminal voltage between 9.5 V and 17.0 V.
• VM/C1 terminal voltage not within 4.4 V and 5.6 V.
5. Both of following conditions continue for at least 1.2
seconds.
• VM/C1 terminal voltage between 4.4 V and 5.6 V.
• PM/C1 terminal voltage not within 0.14 V and 4.85
V.
• Hydraulic brake booster (master cylinder pressure
sensor)
C1281/81 Detected only during test mode
• Master cylinder solenoid (skid control ECU)
• Stop light switch circuit
INSPECTION PROCEDURE
NOTICE:
When replacing the master cylinder solenoid, perform zero point calibration (See page BC-24).
1 READ VALUE OF DATA LIST (MASTER CYLINDER PRESSURE SENSOR)
(a) Connect the intelligent tester to the DLC3.
Intelligent Tester
(b) Start the engine.
(c) Turn the intelligent tester on.
(d) Select the DATA LIST mode on the intelligent tester.
CAN VIM
DLC3
H102157E03
DATA LIST: ABS/VSC
Measurement Item / Range
Item Normal Condition Diagnostic Note
(Display)
• When brake pedal released:
Master cylinder pressure sensor 0.3 to 0.9 V Reading increases when brake
MAS CYL PRS 1
1 reading / min.: 0 V, max.: 5 V • When stop lights turned on: pedal depressed
0.3 to 0.9 V
• When brake pedal released:
Master cylinder pressure sensor 0.3 to 0.9 V Reading increases when brake
MAS CYL PRESS 1
1 reading / min.: 0 V, max.: 5 V • When stop lights turned on: pedal depressed
0.3 to 0.9 V
BRAKE CONTROL – VEHICLE STABILITY CONTROL SYSTEM BC–109
(e) Check that the master cylinder pressure value of the
master cylinder pressure sensor displayed on the
intelligent tester changes when the brake pedal is
depressed.
Result
Result Proceed to
Master cylinder pressure sensor value normal A BC
Master cylinder pressure sensor value changes but not normal B
Master cylinder pressure sensor value does not change C
B Go to step 3
C REPLACE HYDRAULIC BRAKE BOOSTER
2 RECONFIRM DTC
(a) Clear the DTCs (See page BC-45).
(b) Check if the same DTC is detected (See page BC-45).
Result
Result Proceed to
DTC output A
DTC not output B
B END
REPLACE MASTER CYLINDER SOLENOID
3 CHECK BRAKE PEDAL HEIGHT
(a) Check the brake pedal height.
(b) Check the stop light switch installation.
OK:
The brake pedal and stop light switch are normal.
NG ADJUST BRAKE PEDAL HEIGHT
OK
BC–110 BRAKE CONTROL – VEHICLE STABILITY CONTROL SYSTEM
4 INSPECT SKID CONTROL ECU TERMINAL VOLTAGE (STP TERMINAL)
(a) Disconnect the skid control ECU connector.
Skid Control ECU (b) Measure the voltage.
(harness side connector): Standard voltage
BC Tester Connection Condition Specified Condition
STP A4-7 (STP) - Body
Stop light switch ON
A4 (Brake pedal 8 to 14 V
ground
depressed)
A4-7 (STP) - Body Stop light switch OFF
Below 1.5 V
ground (Brake pedal released)
NG REPAIR OR REPLACE HARNESS OR
CONNECTOR
C121700E51
OK
5 RECONFIRM DTC
(a) Clear the DTC (See page BC-45).
(b) Check if the same DTC is detected (See page BC-45).
Result
Result Proceed to
DTC output A
DTC not output B
B END
REPLACE MASTER CYLINDER SOLENOID
