2001 TOYOTA PRIUS Service Repair Manual

DI±214
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check for open, short and +B short in wire harness between HV ECU and accel-
erator pedal position sensor (See page IN±41).
Terminals for checking open and short:
Accelerator pedal position sensor
TerminalsHV ECU Terminals
VCP1VCP1
VPA1VPA1
EP1EP1
VCP2VCP2
VPA2VPA2
EP2EP2
HINT:
The acceleration pedal position sensor circuit has +B short if the voltage at the HV ECU VPA1 or VPA2 termi-
nal is more than 5V with the ignition ON.
NG Repair or replace wire harness.
OK
Check and replace accelerator pedal position sensor (See page SF±59).
DTC P1120 ± Information code 106, 109, 110, 111, 112, 113, 114
INF. code.Detecting ConditionTrouble Area
106Main sensor internal error
109Sub sensor internal error
11 0When difference between main sensor value and sub sensor
value is large
111When sub sensor value changes while main sensor value does
not

Accelerator pedal position sensor
11 2When main sensor value changes while sub sensor value does
not
Accelerator edal osition sensor
11 3When any of the information code 104 ± 112 continues to ap-
pear
11 4Accelerator pedal not smoothly returning to original position
INSPECTION PROCEDURE
If the information code 106 or 109 ± 114 is output,check and replace the accelerator pedal position sensor
(See page SF±59).

A14147
H14Hybrid Vehicle
Control ECU
H14
BatteryMAIN
B±G1 1
F1811 1
111
F13 2
3
2
2 Engine Room J/BSTP
ST1± G±W
J15 E
2 J14D J/C
G±W S3
Stop Light
SW
R±B
R±B4B±Y B±W B±W B
B
J24 J25 ID1J/C
B±W
I15
Ignition SW
W±RW±R
67
9
IG2AM2
Instrument Panel J/B
STOP 2C
2K2H 2G9
1J 1BAM2
B
W
F12 F11
DC/DC
Fusible Link Block No. 1 Fusible Link
Block No. 16
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
DI±215
2001 PRIUS (RM778U)
DTC P1520 Stop Light Switch (Cruise Control System)
Malfunction
CIRCUIT DESCRIPTION
The HV ECU detects the malfunction of the cruise control system and inhibits the operation of the cruise
control.
It detects faulty output of the STP and ST1± signals sent from the stop light switch or an error signal from
the brake ECU.
DTC P1520 ± Information code 115
INF. code.Detecting ConditionTrouble Area
11 5Open or short in stop light switch circuit

Stop light switch

Wire harness

Brake ECU
WIRING DIAGRAM
DI82R±02

DI±216
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Is DTC of brake ECU being output?
YES Check DTC of brake ECU (See page DI±358).
NO
2 Check voltage between terminal 2, 3 of stop light switch and body ground.
NG Repair or replace wire harness or connector.
OK
3 Check for open and short in wire harness between stop light switch and termi-
nals STP, ST1± of HV ECU (See page IN±41).
NG Repair or replace wire harness.
OK
Check and replace stop light switch (See page BE±32).

± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
DI±217
2001 PRIUS (RM778U)
DTC P1566 Cruise Control System Malfunction
CIRCUIT DESCRIPTION
The HV ECU and the brake ECU monitor the same STP signal. If any difference is identified between both
received signals, the HV ECU outputs an error.
DTC P1566 ± Information code 116
INF. code.Detecting ConditionTrouble Area
11 6When STP signal of HV ECU is inconsistent with that of brake
ECU, with cruise control indicator ON.
Brake ECU

Wire harness

Stop light switch
WIRING DIAGRAM
Refer to DI±215.
INSPECTION PROCEDURE
1 Is DTC of brake ECU being output (See page DI±351)?
YES Check DTC of brake ECU (See page DI±351).
NO
2 Check for +B short in wire harness between stop light switch and terminals STP,
ST1±of HV ECU (See page IN±41).
HINT:
Under the normal condition, the voltage of the HV ECU STP terminal is 0V when the brake pedal is released
with the ignition OFF. If there is any output of voltage at this time, the stop light switch circuit has +B short.
NG Repair or replace wire harness.
OK
DI82S±02

DI±218
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
2001 PRIUS (RM778U)
3 Check for open and short in wire harness between stop light switch and brake
ECU.
NG Repair or replace wire harness.
OK
Check and replace stop light switch (See page BE±32).