2001 TOYOTA PRIUS warning light

DI±448
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
5 Check BRAKE warning light.
See combination meter troubleshooting on page BE±2.
NG Repair or replace combination meter.
OK
6 Check multiplex communication system (See page DI±752).
NG Repair or replace multiplex communication cir-
cuit.
OK
Check and replace brake ECU.

F12686
DLC3
2DTc 3
Tc
8
4 CG13ID1 P±B P±B
B11
W±B
AJ11
J/C
A
ID C
Instrument Panel J/BBrake ECU
J16
J/C J26
J/C
J24
J/CP±B P±B
E E
C
W±B W±B
A2K 82
F09678
CG TcDLC3 ON
(+) (±)
DI±452
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
2001 PRIUS (RM778U)
Tc Terminal Circuit
CIRCUIT DESCRIPTION
Connecting terminals Tc and CG of the DLC3 causes the ECU to display the DTC by flashing the ABS warn-
ing light.
WIRING DIAGRAM
INSPECTION PROCEDURE
1 Check voltage between terminals Tc and CG of DLC3.
PREPARATION:
Turn the ignition switch ON.
CHECK:
Measure voltage between terminal Tc and CG of DLC3.
OK:
Voltage: 10 ± 14 V
OK If ABS warning light does not blink even after Tc
and CG are connected, the ECU may be defec-
tive.
NG
DI29I±13

F09679
ON
DLC3 (+) (±)
Ts
CG
± DIAGNOSTICSANTI±LOCK BRAKE SYSTEM WITH EBD & RBS
DI±455
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check voltage between terminals Ts and CG of DLC3.
CHECK:
(a) Turn the ignition switch ON.
(b) Measure voltage between terminals Ts and CG of DLC3.
OK:
Voltage: 10 ± 14 V
OK If ABS warning light does not blink even after Ts
and CG are connected, the ECU may be defec-
tive.
NG
2 Check for open and short circuit in harness and connector between brake ECU
and DLC3, DLC3 and body ground (See page IN±41).
NG Repair or replace harness or connector.
OK
Check and replace brake ECU.

DI7QW±01
F12845
F12874
F12846
Tc
CG
F12873
WL
PGND
± DIAGNOSTICSELECTRIC MOTOR POWER STEERING
DI±459
2001 PRIUS (RM778U)
PRE±CHECK
1. DIAGNOSIS SYSTEM
(a) Check the indicator.
When the ignition switch is turned ON, check that the PS
warning light goes on for 1.5 seconds.
HINT:

If the indicator check result is not normal, proceed to trou-
bleshooting for the PS warning light circuit (See page
DI±486).

When the EMPS system is faulty, the master warning light
in the combination meter and the PS warning light in the
multiinformation display lights up.
(b) In case of not using TOYOTA hand±held tester:
Check the DTC.
(1) Using SST, connect terminals Tc and CG of the
DLC3.
SST 09843±18040
(2) Remove the EMPS ECU with connector still con-
nected.
(3) Connect the both terminals of the 1kW resistance
and LED (Light Emitting Diode) circuit to terminals
WL and PGND of the EMPS ECU.
(4) Turn the ignition switch ON.
(5) Read the DTC from the PS warning light.

F12870
Normal Code
0.25 sec.
0.25 sec.
ON
OFF
ON
OFF0.5 sec.
0.5 sec.
Codes 21 and 22
1.5 sec.2.5 sec.
Code 21Code 22
4 sec.0.5 sec.
F12396
TOYOTA
Hand±held Tester
DLC3
F12861
Ts
CG
DI±460
± DIAGNOSTICSELECTRIC MOTOR POWER STEERING
2001 PRIUS (RM778U)
HINT:

If no code appears, inspect the diagnostic circuit and PS
warning light circuit (See page DI±491 or DI±486).

As an example, the blinking patterns for normal code and
codes 21 and 22 are shown on the left.
(6) Codes are explained in the DTC chart on page
DI±460.
(7) After completing the check, disconnect terminals Tc
and CG of the DLC3, and turn off the display.
If 2 or more malfunctions are indicated at the same
time, the lowest numbered DTC will be displayed
first.
(c) In case of using TOYOTA hand±held tester:
Check the DTC.
(1) Hook up the TOYOTA hand±held tester to the
DLC3.
(2) Turn the ignition switch ON.
(3) Read the DTC by following the prompts on the tes-
ter screen.
HINT:
Please refer to the TOYOTA hand±held tester operator's manu-
al for further details.
(d) In case of not using TOYOTA hand±held tester:
Clear the DTC.
(1) Using SST, connect terminals Ts and CG of DLC3.
SST 09843±18040
(2) Turn the ignition switch ON.
(3) ON and OFF the terminal CG of the DLC3 4 times
or more within 8 seconds, delete DTC of the EMPS
ECU.
(4) Check that the PS warning light shows the normal
code.
(5) Remove the SST from the DLC3.
SST 09843±18040

F12396
TOYOTA
Hand±held Tester
DLC3
F12848
Tc
CG
Ts
F12871
Malfunction Code (Example Code 72)
7
2
ON
OFF
0.5 sec. 0.5 sec.
0.5 sec.
1.5 sec.4 sec.
Repeat
0.5 sec. ON
OFF
0.25 sec.
0.25 sec. Normal Code
A Cycle
± DIAGNOSTICSELECTRIC MOTOR POWER STEERING
DI±461
2001 PRIUS (RM778U)
(e) In case of using TOYOTA hand±held tester:
Clear the DTC.
(1) Hook up the TOYOTA hand±held tester to the
DLC3.
(2) Turn the ignition switch ON.
(3) Operate the TOYOTA hand±held tester to erase the
codes. (See TOYOTA hand±held tester operator's
manual.)
2. INPUT SIGNAL CHECK (TEST MODE)
(a) In case of not using TOYOTA hand±held tester:
Check the input signal.
(1) Turn the ignition switch OFF.
(2) Using SST, connect terminals Ts and CG of DLC3.
SST 09843±18040
(3) Check the warning light goes off with driving more
than 20 km/h (12 mph).
HINT:
If the warning light goes off during driving, the sensor can be
judged to normal.
(4) Stop the vehicle.
(5) Using SST, connect terminals Tc and CG of DLC3.
SST 09843±18040
(6) Read the number of blinks of the PS warning light.
HINT:

See the list of DTC shown on the next page.

Even a sensor is normal, it output codes 71 and 72 during
test mode.
(7) After doing check, disconnect the SST from the ter-
minals Ts and CG, Tc and CG of DLC3, and turn the
ignition switch OFF.
SST 09843±18040

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