2001 TOYOTA PRIUS Service Repair Manual

DI±274
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
2001 PRIUS (RM778U)
INSPECTION PROCEDURE
1 Check for open, short and +B short in wire harness between HV ECU MIT and
MIVG terminals and converter & inverter M±INVT, M±GINV terminals (See page
IN±41).
HINT:
Confirm that there is no open circuit in the wire harness. If the voltage between the HV ECU MIT or MIVG
terminal and body ground is always more than 5V with the ignition ON, the motor inverter temperature sensor
circuit has +B short.
NG Repair or replace wire harness.
OK
Check for open in motor inverter temperature sensor and then replace converter & inverter as-
sembly. Check motor inverter temperature sensor (See page HV±14).

A14121
InverterHybrid Vehicle Control ECU
M±SINVG 7
I10
6
I9 M±GINVB21
MSIV
MIVG 26
H11H11
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
DI±275
2001 PRIUS (RM778U)
CIRCUIT DESCRIPTION
The HV ECU checks the line connection of the motor inverter stop signal circuit and enters the fail safe mode
(limited output driving) if malfunction is detected.
DTC P3125 ± Information code 278, 280
INF. Code.Detecting ConditionTrouble Area
278+B short in motor inverter stop signal circuit
Converter & inverter assembly
280Open or GND short in motor inverter stop signal circuit

Converter & inverter assembly

Wire harness
WIRING DIAGRAM
INSPECTION PROCEDURE
1 Check for open, short and +B short in wire harness between HV ECU MSIV and
MIVG terminals and converter & inverter assembly M±SINV and M±GIVN termi-
nals (See page IN±41).
HINT:
The motor inverter stop signal circuit has +B short if the voltage between the HV ECU MSIV or MIGV terminal
and body ground is always more than 13 V with the ignition ON (ºREADYº light OFF).
NG Repair or replace wire harness.
OK
Replace converter & inverter assembly.

DI±276
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
2001 PRIUS (RM778U)
CIRCUIT DESCRIPTION
DTC P3125 ± Information code 279, 281, 282
INF. Code.Detecting ConditionTrouble Area
279Over voltage of inverter
281Voltage drop of inverter power source
Converter & inverter assembly
282Inverter circuit broken
Converter & inverter assembly
INSPECTION PROCEDURE
If the information code 279 or 281 is output, check if other DTC or information codes are recorded. If they
are recorded, check and repair those codes first.
If the information code 279 or 281 alone is recorded, replace the converter & inverter assembly.
If the information code 282 is output, replace the converter & inverter assembly.

A14121
InverterHybrid Vehicle Control ECU
M±GINVB 6
I9
8
I10 M±FINVB26
MFIV 14 H11
H11MIVG
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
DI±277
2001 PRIUS (RM778U)
CIRCUIT DESCRIPTION
The HV ECU checks the line connection of the motor inverter fail signal circuit and detects malfunction.
DTC P3125 ± Information code 283, 285
INF. Code.Detecting ConditionTrouble Area
283+B short in motor inverter fail signal circuit
Converter & inverter assembly
285Open or GND short in motor inverter fail signal circuit

Converter & inverter assembly

Wire harness
WIRING DIAGRAM
INSPECTION PROCEDURE
1 Check for open, short and +B short in wire harness between HV ECU MFIV and
MIVG terminals and converter & inverter assembly M±FINV and M±GINV termi-
nals (See page IN±41).
HINT:
The motor inverter fail signal circuit has +B short if the voltage between the HV ECU MIVG or MFIV terminal
and body ground is always more than 13 V with the ignition ON (ºREADYº light OFF).
NG Repair or replace wire harness.
OK
Replace converter & inverter assembly.

DI±278
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
2001 PRIUS (RM778U)
CIRCUIT DESCRIPTION
DTC P3125 ± Information code 284, 286, 287
INF. Code.Detecting ConditionTrouble Area
284Inverter overheating
286Inverter circuit broken
Converter & inverter assembly
287Inverter internal short
Converter & inverter assembly
INSPECTION PROCEDURE
If the information code 284 or 287 is output, check if other DTC or information codes are recorded. If they
are recorded, check and repair those codes first.
If the information code 284 or 287 alone is recorded, replace the converter & inverter assembly.
If the information code 286 is output, replace the converter & inverter assembly.

A14123
InverterHybrid Vehicle Control ECU
M±GINVB
2
I10 M±IWAR B
W
G 4
I103
I101
I106
I9
M±IWB M±IVB M±IVAMIVG
MIWAMIWB MIVB MIVA 26
16
7
17
25
H11 H11 H11 H11 H11
± DIAGNOSTICSHYBRID VEHICLE CONTROL SYSTEM
DI±279
2001 PRIUS (RM778U)
CIRCUIT DESCRIPTION
The HV ECU detects the malfunction of the motor inverter current sensor. It detects the malfunction of the
sensor system, not of the high voltage system.
DTC P3125 ± Information code 288, 289, 290, 292, 294, 296, 297, 298, 300, 302,
INF. Code.Detecting ConditionTrouble Area
289Open in motor inverter current sensor (V phase sub sensor)
292Open in motor inverter current sensor (V phase main sen-
sor)
297Open in motor inverter current sensor (W phase sub sen-
sor)
300Open in motor inverter current sensor (W phase main sen-
sor)
288Motor inverter current sensor malfunction (V phase sub
sensor)
Ct&it bl
290Motor inverter current sensor malfunction (V phase main
sensor)
Converter & inverter assembly

Wire harness
294Motor inverter current sensor V phase performance prob-
lem
296Motor inverter current sensor malfunction (W phase sub
sensor)
298Motor inverter current sensor malfunction (W phase main
sensor)
302Motor inverter current sensor W phase performance prob-
lem
WIRING DIAGRAM