Nissan Altima HL32 Hybrid. Manual - part 631

P0A78-306

HBC-273

< COMPONENT DIAGNOSIS >

D

E

F

G

H

I

J

K

L

M

A

B

HBC

N

O

P

OK

>> GO TO 4.

NG

>> Connect securely.

4.

CHECK INVERTER WITH CONVERTER ASSEMBLY (MOTOR CABLE CONNECTION CONDITION)

See 

HBC-177, "Diagnosis Procedure"

.

OK or NG

OK

>> GO TO 5.

NG

>> Tighten to specified torque.

5.

INSPECT HYBRID TRANSAXLE (MG2)

See 

HBC-177, "Diagnosis Procedure"

.

OK or NG

OK

>> Replace inverter with converter assembly (See 

HBC-638, "Removal and Installation"

).

NG

>> Replace hybrid transaxle (See 

TM-36, "Removal and Installation"

).

HBC-274

< COMPONENT DIAGNOSIS >

P0A78-503, P0A78-504

P0A78-503, P0A78-504

Description

INFOID:0000000004211936

The inverter converts high-voltage direct current from the HV battery and alternating current for MG2 and

MG1. The inverter contains a three-phase bridge circuit, which consists of six power transistors each for MG2

and MG1, that converts direct current to three-phase alternating current. The MG ECU controls the actuation

of the power transistors. The inverter transmits information that is necessary for effecting control, such as the

amperage and voltage, to the MG ECU.

The MG ECU uses a voltage sensor, which is built into the inverter, to detect boosted high voltage to allow

control of the voltage boost.

The inverter voltage sensor outputs voltage that varies between 0 and 5 V in accordance with the changes in

the high voltage. The higher the high voltage, the higher the output voltage, and the lower the high voltage, the

lower the output voltage.

P0A78-503, P0A78-504

HBC-275

< COMPONENT DIAGNOSIS >

D

E

F

G

H

I

J

K

L

M

A

B

HBC

N

O

P

The MG ECU monitors the inverter voltage and detects malfunctions.

DTC Logic

INFOID:0000000004211937

DTC DETECTION LOGIC

If the motor inverter detects overvoltage, it transmits an overvoltage signal to the MG ECU. Upon receiving this

signal, the hybrid vehicle control ECU will illuminate the MIL and set a DTC.

JMCIA0099GB

HBC-276

< COMPONENT DIAGNOSIS >

P0A78-503, P0A78-504

Diagnosis Procedure

INFOID:0000000004211938

1.

PRECONDITIONING

• Before inspecting the high-voltage system or disconnecting the low voltage connector of the inverter with

converter assembly, take safety precautions such as wearing insulated gloves and removing the service

plug grip to prevent electrical shocks. After removing the service plug grip, put it in your pocket to prevent

other technicians from accidentally reconnecting it while you are working on the high-voltage system.

• After disconnecting the service plug grip, wait for at least 10 minutes before touching any of the high-voltage

connectors or terminals.

• Waiting for at least 10 minutes is required to discharge the high-voltage capacitor inside the inverter with

converter assembly.

>> GO TO 2.

2.

CHECK DTC OUTPUT (HYBRID SYSTEM)

1. Turn ignition switch ON.

2. Check DTC.

NOTE:

P0A78-503 or 504 may be set due to a malfunction which also causes DTCs in the table above to be set.

In this case, first troubleshoot the output DTCs in the table above. Then, perform a test to attempt to

reproduce the problems, and check that no DTCs are output.

DTC No.

INF Code

Trouble diagnosis name

DTC detecting condition

Possible cause

P0A78

503

Drive Motor “A” Inverter 
Performance

Motor inverter overvoltage signal de-
tection (overvoltage due to MG ECU 
malfunction)

• Wire harness or connector
• Inverter with converter assembly
• Hybrid transaxle

504

Motor inverter overvoltage signal de-
tection (overvoltage due to hybrid 
transaxle malfunction)

DTC No.

Relevant Diagnosis

P0A1D (Except INF code 390)

Hybrid Powertrain Control Module

P0A1A (all INF codes)

Generator Control Module

P0A1B (all INF codes)

Drive Motor “A” Control Module

P0A72 (all INF codes)

Generator Phase V Current

P0A75 (all INF codes)

Generator Phase W Current

P0A60 (all INF codes)

Drive Motor “A” Phase V Current

P0A63 (all INF codes)

Drive Motor “A” Phase W Current

P0A4B-253

Generator Position Sensor Circuit

P0A4D-255

Generator Position Sensor Circuit Low

P0A4C-513

Generator Position Sensor Circuit Range/Performance

P0A3F-243

Drive Motor “A” Position Sensor Circuit

P0A41-245

Drive Motor “A” Position Sensor Circuit Low

P0A40-500

Drive Motor “A” Position Sensor Circuit Range / Performance

P0A78-266, 267, 523, 586, 505, 287, 506, 806, 807, 808

Drive Motor “A” Inverter Performance

P0A94-585, 587, 589, 590, 554, 555, 556

DC/DC Converter Performance

P0A7A-517, 325, 518, 809, 810, 811

Generator Inverter Performance

P3004-803

High Voltage Power Resource

P0ADB-227

Hybrid Battery Positive Contactor Control Circuit Low

P0ADC-226

Hybrid Battery Positive Contactor Control Circuit High

P0ADF-229

Hybrid Battery Negative Contactor Control Circuit Low