2001 TOYOTA PRIUS Service Repair Manual

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.

A14124
InverterHybrid Vehicle
Control ECU
G 3
I91
I9 M±VUW6
H11
5
H11MWU
MVU MUU 4
H11 R I9
2 M±UU M±WU DI±270
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
2001 PRIUS (RM778U)
CIRCUIT DESCRIPTION
The HV ECU detects faulty line connection inside the inverter.
DTC P3125 ± Information code 272
INF. Code.Detecting ConditionTrouble Area
272
Abnormality of line connection of motor PWM (when there
is a history that the state of malfunction continued during
inverter fail safe mode)
Wire harness

Converter & inverter assembly
WIRING DIAGRAM

± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
DI±271
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check open and short in wire harness between HV ECU terminals (MUU, MVU,
MWU) and inverter terminals.
NG Repair or replace wire harness.
OK
2 Is there DTC P3100 being output?
YES Check applicable DTC.
NO
Replace converter & inverter assembly.

A14120
InverterHybrid Vehicle
Control ECU
M±SDOWNY 4
I913
MSDN
H11
DI±272
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
2001 PRIUS (RM778U)
CIRCUIT DESCRIPTION
The HV ECU detects faulty line connection inside the inverter.
DTC P3125 ± Information code 273
INF. Code.Detecting ConditionTrouble Area
273Motor inverter malfunction
Converter & inverter assembly

Wire harness
WIRING DIAGRAM
INSPECTION PROCEDURE
1 Check for open and short in wire harness between HV ECU MSDN terminal and
converter & inverter M±SDOWN terminal.
NG Repair or replace wire harness.
OK
Replace converter & inverter assembly.