2001 TOYOTA PRIUS brake light

F12396
TOYOTA
Hand±held Tester
DLC3
DI±462
± DIAGNOSTICSELECTRIC MOTOR POWER STEERING
2001 PRIUS (RM778U)
(b) In case of using TOYOTA hand±held tester:
Check the input signal.
(1) Hook up the TOYOTA hand±held tester to the
DLC3.
(2) Check the warning light goes off with driving more
than 20 km/h (12 mph).
(3) Read the DTC by following the prompts on the tes-
ter screen.
HINT:

Please refer to the TOYOTA hand±held tester operator's
manual for further details.

See the list of DTC shown on the bottom of this page.

Even a sensor is normal, it output codes 71 and 72 during
test mode.
DTC of input signal check function:
Code No.
(See page)DiagnosisTrouble Area
C1515/15
(DI±468)Calibration of torque sensor zero point Not Performed±
C1516/16
(DI±469)Calibration of torque sensor zero point Not completed±
C1571/71
C1572/72
(DI±474)
Speed sensor malfunction (Test mode)

Right rear or left rear speed sensor

Sensor installation

Right rear or left rear speed sensor rotor

Right rear or left rear speed sensor circuit

Brake ECU

EMPS ECU
3. CALIBRATION OF TORQUE SENSOR ZERO POINT
HINT:
Perform this operation in the following cases.

When removing and installing ºsteering wheelº, ºtilt steer-
ing columnºand ºelectric power steering gearº.

When replacing EMPS ECU.
(a) Place front wheels and steering wheel facing straight
ahead.
(b) In case of using TOYOTA hand±held tester:
Perform the torque sensor zero point initialization.
HINT:
If the EMPS ECU is replaced, however, this operation is not
necessary.
(1) Stop the vehicle.

DI7QX±01
± DIAGNOSTICSELECTRIC MOTOR POWER STEERING
DI±465
2001 PRIUS (RM778U)
DIAGNOSTIC TROUBLE CODE CHART
HINT:

Using SST 09843±18040, connect terminals Tc and CG of the DLC3.

If a malfunction code is displayed during the DTC check, check the circuit listed for the code. For details
of each code, turn to the page referred to under the ºSee pageº for respective ºDTC No.º in the DTC
chart.
DTC No.
(See page)Detection ItemTrouble Area
C1511/11
(DI±465)
C1512/12
(DI±465)
T i it lf ti
Torque sensor
C1513/13
(DI±465)Torque sensor circuit malfunction
Torque sensor

EMPS ECU
C1514/14
(DI±465)
C1521/21
(DI±471)
C1522/22
(DI±471)
Mt i it lf ti
Power steering gear assembly with motor
C1523/23
(DI±471)Motor circuit malfunction
Power steering gear assembly with motor

EMPS ECU
C1524/24
(DI±471)
C1531/31
(DI±473)
C1532/32
(DI±473)EMPS ECU malfunctionEMPS ECU
C1533/33
(DI±473)
C1541/41
(DI±474)
C1542/42
(DI±474)Speed sensor malfunction

Speed sensor

Brake ECU

EMPS ECUC1543/43
(DI±474)
EMPS ECU
C1551/51
(DI±476)IG power source circuit malfunction

EMPS ECU

Power source circuit

Charging system
C1552/52
(DI±479)PIG power source drop voltage malfunction
EMPS ECU

Power source circuit
C1553/53
(DI±482)When resetting voltage, vehicle is being drivenEMPS ECU
C1554/54
(DI±483)EMPS relay circuit malfunction

EMPS relay

EMPS ECU

EMPS relay circuit
C1555/55
(DI±473)EMPS ECU malfunctionEMPS ECU
C1556/56
(DI±486)P/S warning light circuit
Multiinformation display

EMPS ECU

DI±654
± DIAGNOSTICSCRUISE CONTROL SYSTEM
2001 PRIUS (RM778U)
CIRCUIT INSPECTION
DTC P1520 Stop light switch circuit
CIRCUIT DESCRIPTION
When the brake pedal is depressed, the stop light switch sends a signal to the hybrid vehicle control ECU.
When the hybrid vehicle control ECU receives this signal, it cancels the cruise control.
A fail±safe function is provided so that the cancel functions normally, even if there is a malfunction in the stop
light signal circuit.
The cancel condition is that battery voltage is supplied to terminal STP.
When the brake is on, battery voltage is normally applied through the STOP fuse and stop light switch to
terminal STP of the hybrid vehicle control ECU, and the hybrid vehicle control ECU turns the cruise control
OFF.
If the harness connected to terminal STP has an open circuit, terminal STP will have battery voltage and
the cruise control will be turned OFF.
DTC No.Detection ItemTrouble Area
P1520Stop light switch circuit.

Stop light switch

Harness or connector between hybrid vehicle control ECU
and stop light switch circuit

Hybrid vehicle control ECU
DI7NI±01

I19096
ON
STP
(+) (±)
DI±656
± DIAGNOSTICSCRUISE CONTROL SYSTEM
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check operation of stop light.
CHECK:
Check that stop light comes on when brake pedal is depressed, and turns off when brake pedal is released.
NG Check stop light system (See page BE±2).
OK
2 Check voltage between terminal STP of hybrid vehicle control ECU connector
and body ground.
PREPARATION:
(a) Remove the hybrid vehicle control ECU with connectors
still connected.
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminal STP of hybrid vehicle con-
trol ECU connector and body ground, when the brake pedal is
depressed and released.
OK:
Depressed10 ± 14 V
ReleasedBelow 1 V
OK Proceed to next circuit inspection shown in
problem symptom table (See page DI±648).
NG

I19096
ON
ST1±
(+) (±)
± DIAGNOSTICSCRUISE CONTROL SYSTEM
DI±657
2001 PRIUS (RM778U)
3 Check voltage between terminal ST1± of hybrid vehicle control ECU connector
and body ground.
PREPARATION:
(a) Remove the hybrid vehicle control ECU with connectors
still connected.
(b) Turn ignition switch ON.
CHECK:
Measure voltage between terminal ST1± of hybrid vehicle con-
trol ECU connector and body ground, when the brake pedal is
depressed and released.
OK:
DepressedBelow 1 V
Released10 ± 14 V
OK Proceed to next circuit inspection shown in
problem symptoms table (See page DI±648).
NG
4 Check wire harness and connector between terminal STP of hybrid vehicle con-
trol ECU and stop light switch, and terminal ST1± of hybrid vehicle control ECU
and stop light switch (See page IN±41).
NG Repair or replace harness or connector.
OK
Check and replace hybrid vehicle control
ECU (See page DI±174
).

DI7XS±01
DI±674
± DIAGNOSTICSCOMBINATION METER SYSTEM
2001 PRIUS (RM778U)
PROBLEM SYMPTOMS TABLE
TROUBLESHOOTING:
Flow chart No.SymptomSee page
1Check the communication between the combination meter and the multiplex com-
munication circuit.DI±671
2The whole meter does not functionDI±672
3The margin of error in speedometer is large. Or it remains as 0 mph.DI±673
4Fuel receiver gauge is inoperative or improper.DI±674
5Indicators or warning lights do not light up.DI±676
Fuel gauge:
SymptomSuspect AreaSee page
Displayed level is higher or lower than the actual level.1. Inclination sensor resetting
2. Body ECUBE±47
IN±41
General:
SymptomSuspect area
Meter display does not properly function.3. Combination meter ECU
Entirely black screen appears.1. Fuse
2. Wire harness and connector
3. Combination meter ECU
Turning the light control switch ON does not dim the light.1. Illumination switch
2. Wire harness and connector
3. Combination meter ECU
Brightness cannot be changed by the illumination switch operation.1. Illumination switch
2. Wire harness and connector
3. Combination meter ECU
Speedometer:
SymptomSuspect area
Improper display (Remained as 0 km/h)1. Accessory that utilizes vehicle speed signals
2. Brake ECU
3. Combination meter ECU
4. Wire harness and connector
Speedometer only does not light up.1. Combination meter ECU
Abnormal display (Incomplete numbers displayed)1. Combination meter ECU
DIsplayed value changes frequently or sharply.1. Accessory that utilizes vehicle speed signals
2. Brake ECU
3. Combination meter ECU
4. Wire harness and connector
Margin of error in speedometer is large.1. Accessory that utilizes vehicle speed signals
2. Brake ECU
3. Combination meter ECU
4. Wire harness and connector
ODO/TRIP Meter:
SymptomSuspect area
ODO/TRIP only does not light up.1. Combination meter ECU
Abnormal display (Incomplete number displayed)1. Combination meter ECU
Both meters do not integrate values. (When speedometer is normal)1. Combination meter ECU
Trip meter only does not integrate values.1. ODO/TRIP switch
2. Combination meter ECU

± DIAGNOSTICSCOMBINATION METER SYSTEM
DI±675
2001 PRIUS (RM778U) Trip meter cannot be reset.
1. ODO/TRIP switch
2. Combination meter ECU
Display cannot be shifted among ODO, TRIPA and TRIPB.1. ODO/TRIP switch
2. Combination meter ECU
Without resetting, the display returns to 0.0 km.1. ODO/TRIP switch
2. +B wire harness
3. Combination meter ECU
Error of accumulated distance is large.1. Accessory that utilizes vehicle speed signals.
2. GND wire harness
3. Brake ECU
4. Wire harness and connector
5. Combination meter ECU
Others:
SymptomSuspect area
Some indicators or warning lights are always ON.1. Meter circuit plate
2. Corresponding switch and ECU
3. Combination meter ECU
4. Multiplex communication circuit
Some indicators or warning lights do not light up.1. Bulb
2. Meter circuit plate
3. Corresponding switch and ECU
4. Combination meter ECU
5. Multiplex communication circuit
Buzzer does not stop.1. Combination meter ECU
2. Corresponding switch and ECU

I15461
Display
check screen switch
DI±812
± DIAGNOSTICSNAVIGATION SYSTEM
2001 PRIUS (RM778U)
(e) VEHICLE SIGNAL CHECK MODE SCREEN
(1) Status of the Vehicle Signal which has been loaded into the display is checked in this screen.
(2) Signal Description
Battery: Displays battery voltage in V.
IG: Displays ON or OFF of the ignition switch.
PKB: Displays ON (applied) or OFF (released) of the parking brake.
SPEED: Displays the vehicle speed in km/h.
TAIL: Displays ON or OFF of the tail light switch.
(3) Display Check Screen Switch
Pressing this switch activates the Display Check Mode screen.