TOYOTA PRIUS 2001 Service Repair Manual

A14122
Motor Generator No. 1Hybrid Vehicle
Control ECU
7
M2
2
M2
1
M2
6
M2
3
M2
8
M2G
RGSNG
GSN
GRF
GRFG
GCS
GCSG B
W
Y
BR11
H10
4
H10
10
H10
17
H10
5
H10
12
H10 GSNG
GSN
GRF
GRFG
GCS
GCSG DI±260
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
2001 PRIUS (RM778U)
CIRCUIT DESCRIPTION
The HV ECU checks the generator resolver signal voltage and circuit impedance to detect malfunction.
DTC P3120 ± Information code 253, 255
INF. Code.Detecting ConditionTrouble Area
253Generator resolver inter±phase short
HV transaxle (generator)
255Open or short in generator resolver circuit

HV transaxle (generator)

Wire harness
WIRING DIAGRAM

± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
DI±261
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check for open and short in wire harness between HV transaxle and HV ECU
(See page IN±41).
Terminals for checking open and short:
MG1 TerminalsHV ECU Terminals
GSNGGSNG
GSNGSN
GCSGCS
GCSGGCSG
GRFGRF
GRFGGRFG
NG Repair or replace wire harness.
OK
Check for open in generator resolver or inter±phase short and then replace HV transaxle genera-
tor.
Check generator resolver (See page HV±40).

A14122
Motor Generator No. 1Hybrid Vehicle
Control ECU
7
M2
2
M2
1
M2
6
M2
3
M2
8
M2G
RGSNG
GSN
GRF
GRFG
GCS
GCSG B
W
Y
BR11
H10
4
H10
10
H10
17
H10
5
H10
12
H10 GSNG
GSN
GRF
GRFG
GCS
GCSG DI±262
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
2001 PRIUS (RM778U)
CIRCUIT DESCRIPTION
The HV ECU checks the generator resolver signal voltage and circuit impedance to detect malfunction.
DTC P3120 ± Information code 254, 256
INF. Code.Detecting ConditionTrouble Area
254
Generator resolver inter±phase short (when there is a histo-
ry that the state of malfunction continued during inverter fail
safe mode)

HV transaxle (generator)
256
Open or short in generator resolver circuit (when there is a
history that the state of malfunction continued during invert-
er fail safe mode)

HV transaxle (generator)

Wire harness
WIRING DIAGRAM

± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
DI±263
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check for open and short in wire harness between HV transaxle and HV ECU
(See page IN±41).
Terminals for checking open and short:
MG2 TerminalsHV ECU Terminals
MSNGMSNG
MSNMSN
MCSMCS
MCSGMCSG
MRFMRF
MRFGMRFG
NG Repair or replace wire harness.
OK
2 Is there DTC P3100 being output?
YES Check applicable DTC.
NO
3 Is there DTC P3125 being output?
YES Check applicable DTC.
NO
Replace HV transaxle generator.

A14121
Motor Generator No. 1Hybrid Vehicle
Control ECU
4
M2
9
M2B±R
GMT
GMTG G±W1
H10
8
H10 GMT
GMTG DI±264
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
2001 PRIUS (RM778U)
CIRCUIT DESCRIPTION
The HV ECU checks the generator temperature and controls the load limitation in order to prevent the gener-
ator from overheating. Also, it detects the abnormality of the line connection of the generator temperature
sensor and the malfunction of the sensor itself.
DTC P3120 ± Information code 257, 259
INF. Code.Detecting ConditionTrouble Area
257GND short in generator temperature sensor
HV transaxle
259Open or +B short in generator temperature sensor

HV transaxle

Wire harness
WIRING DIAGRAM

± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
DI±265
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check for open, short and +B short in wire harness between HV transaxle gener-
ator temperature sensor GMT and GMTG terminals and HV ECU GMT and GMTG
terminals (See page IN±41).
HINT:
Confirm that there is no open circuit in the wire harness. If the voltage of the HV ECU GMT terminal is always
more than 5V with the ignition ON, the generator temperature sensor circuit has +B short.
NG Repair or replace wire harness.
OK
Check for open in generator temperature sensor and then replace HV transaxle generator.
Check generator temperature sensor (See page HV±40).
CIRCUIT DESCRIPTION
DTC P3120 ± Information code 258, 260
INF. Code.Detecting ConditionTrouble Area
258Generator temperature sensor malfunctionHV t l ( t )260Generator temperature sensor performance problem
HV transaxle (generator)
INSPECTION PROCEDURE
If the information code 258 or 260 is output, replace the HV transaxle generator.

A14140
C4
ConverterHybrid Vehicle
Control ECU
NODD
4L ± O
NODD 4
H12 DI±266
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
2001 PRIUS (RM778U)
DTC P3125 Converter & Inverter Assembly Malfunction
CIRCUIT DESCRIPTION
If driving the vehicle with the DCDC converter malfunctioning, the voltage of the auxiliary battery will drop,
which will make it impossible to keep driving the vehicle. Therefore, HV ECU checks the operation of the
DCDC converter and gives warning to the driver if malfunction is detected.
HINT:

When using an OBD scan tool other than TOYOTA hand±held tester, check all the steps.

When using TOYOTA hand±held tester, confirm the information code and check it.
DTC P3125 ± Information code 263, 264, 265
INF. Code.Detecting ConditionTrouble Area
263+B short in DCDC converter NODD wiring
264DCDC converter malfunction
Converter & inverter assembly

Wire harness265Open or GND short in DCDC converter NODD wiring
Wire harness
WIRING DIAGRAM
DI838±02

± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
DI±267
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check for open, short and +B short in wire harness between HV ECU NODD ter-
minal and converter & inverter NODD terminal (See page IN±41).
HINT:
The converter has +B short if the battery voltage is always applied to the HV ECU NODD terminal with the
ignition ON.
NG Repair or replace wire harness.
OK
Replace converter & inverter assembly.

A14121
InverterHybrid Vehicle
Control ECU
VBY 5
I10
6
I9 M±GINVB20
H11
26
H11VB
MIVG DI±268
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
2001 PRIUS (RM778U)
CIRCUIT DESCRIPTION
The HV ECU checks the inverter voltage and detects malfunction.
DTC P3125 ± Information code 266, 267, 268, 269, 270
INF. Code.Detecting ConditionTrouble Area
266Open or GND short in inverter voltage signal circuit
267+B short in inverter voltage signal circuit
268Inverter voltage signal is inconsistent with battery voltage
Converter & inverter assembly269Inverter voltage sensor malfunction
Converter & inverter assembly

Wire harness
270
Abnormality of line connection of inverter voltage signal
circuit (when there is a history that the state of malfunction
continued during inverter fail safe mode)

Wire harness
WIRING DIAGRAM

± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
DI±269
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check for open, short and +B short in wire harness between HV ECU VB and
MIVG terminals and converter & inverter assembly VB and M±GINV terminal (See
page IN±41).
HINT:
Confirm that there is no open circuit in the wire harness. If the voltage between the HV ECU VB or MIVG
terminal and body ground is always more than 5V with the ignition ON, the inverter voltage signal circuit has
+B short.
NG Repair or replace wire harness.
OK
2 Is there DTC P3100 being output?
YES Check applicable DTC.
NO
Replace converter & inverter assembly.