Nissan Altima HL32 Hybrid. Manual - part 607

P0A1B-788

HBC-177

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P0A1B-788

Description

INFOID:0000000004211828

If the inverter with converter assembly (MG ECU) is reset due to a problem with the power source in the

inverter, the hybrid vehicle control ECU will set this DTC.

NOTE:

Clearing the DTCs using the CONSULT-III when DTC U0110-657 is detected and the problem is still occurring

will cause DTC P0A1B-788 to be stored. However, it is not necessary to perform inspection for DTC P0A1B-

788 because DTC P0A1B-788 indicates a communication system malfunction.

DTC Logic

INFOID:0000000004211829

DTC DETECTION LOGIC

If an abnormal power source IC CPU reset is detected in the MG ECU, the hybrid vehicle control ECU will illu-

minate the MIL and set a DTC.

Diagnosis Procedure

INFOID:0000000004211830

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 CONNECTOR CONNECTION CONDITION (INVERTER WITH CONVERTER ASSEMBLY CON-

NECTOR)

See 

HBC-109, "Diagnosis Procedure"

.

DTC No.

INF code

Trouble diagnosis name

DTC detecting condition

Possible cause

P0A1B

788

Drive Motor “A” Control Module

Error in reset signal from power 
source IC

• Wire harness or connector
• Inverter with converter assembly 

(MG ECU)

• Hybrid transaxle

JMCIA0190GB

HBC-178

< COMPONENT DIAGNOSIS >

P0A1B-788

OK or NG

OK

>> GO TO 3.

NG

>> Connect securely.

3.

CHECK HARNESS AND CONNECTOR (INVERTER WITH CONVERTER ASSEMBLY - HIGH VOLTAGE

FUSE AND FUSIBLE LINK BOX)

CAUTION:

Be sure to wear insulated gloves.

1. Turn ignition switch OFF and remove the service plug grip (See 

HBC-632, "Precautions for Inspecting the

Hybrid Control System"

).

NOTE:

After removing the service plug grip, do not turn ignition switch to READY position, unless instructed by

the service manual because this may cause a malfunction.

2. Remove the IGCT relay from the high voltage fuse and fusible link box.

3. Disconnect the inverter with converter assembly harness connector E69.

4. Measure the resistance according to the value(s) in the table below.

Check for open

Check for short

5. Remove 10A fuse (No. 67).

6. Measure the resistance according to the value(s) in the table below.

Check for short

OK or NG

OK

>> GO TO 4.

NG

>> Repair or replace harness or connector.

4.

CHECK INVERTER WITH CONVERTER ASSEMBLY (MOTOR CABLE CONNECTION CONDITION)

CAUTION:

Be sure to wear insulated gloves.

1. Check that the service plug grip is not installed.

Inverter with converter assembly

High voltage fuse and fusible link 

box

Resistance

Harness

connector

Terminal

Harness

connector

Terminal

E69

1 (+B)

V-1

5 (IGCT relay)

Below 1 

Ω

2 (+B2)

Inverter with converter assembly

Ground

Resistance

Harness

connector

Terminal

E69

3 (GND1)

Ground

Below 1 

Ω

4 (GND2)

Inverter with converter assembly

Ground

Resistance

Harness

connector

Terminal

E69

1 (+B)

Ground

150 

Ω or higher

2 (+B2)

Inverter with converter assembly

Ground

Resistance

Harness

connector

Terminal

E69

1 (+B)

Ground

10 k

Ω or higher

2 (+B2)

P0A1B-788

HBC-179

< COMPONENT DIAGNOSIS >

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2. Check that the bolts for the motor cable are tightened to the

specified torque.

NOTE:

Make sure that the tightening torque of the bolts is between 3.0

and 5.0 N·m (0.3 and 0.5 kg-m, 27 and 44 in-lb).

OK or NG

OK

>> GO TO 5.

NG

>> Tighten to specified torque.

5.

CHECK INVERTER WITH CONVERTER ASSEMBLY (GENERATOR CABLE CONNECTION CONDITION)

CAUTION:

Be sure to wear insulated gloves.

1. Check that the service plug grip is not installed.

2. Check that the bolts for the generator cable are tightened to the

specified torque.

NOTE:

Make sure that the tightening torque of the bolts is between 3.0

and 50 N·m (0.3 and 0.5 kg-m, 27 and 44 in-lb).

OK or NG

OK

>> GO TO 6.

NG

>> Tighten to specified torque.

6.

INSPECT HYBRID TRANSAXLE (MG1)

CAUTION:

Be sure to wear insulated gloves.

1. Check that the service plug grip is not installed.

2. Disconnect the generator cable and motor cable from the inverter with converter assembly (See 

HBC-

638, "Removal and Installation"

).

3. Check that dirt or foreign objects have not entered the connection, or there is no evidence of contamina-

tions.

4. Using a milliohmmeter, measure the resistance according to the

value(s) in the table below. (Check MG1 for an interphase

short.)

NOTE:

If the MG1 temperature is high, the resistance varies greatly.

Therefore, measure the resistance at least 8 hours after the

vehicle is stopped.

NOTE:

To correct the variation of the measured resistance due to temperature, use the following formula to calcu-

late the resistance at 20

°C.

Torque

: 4.0 N·m (0.4 kg-m, 35 in-lb)

ALCIA0105ZZ

Torque

: 4.0 N·m (0.4 kg-m, 35 in-lb)

ALCIA0106ZZ

Terminal

Terminal

Resistance

U

V

59 to 65 m

Ω

V

W

56 to 62 m

Ω

W

U

56 to 62 m

Ω

R20 = Rt / [1 + 0.00393 X (T - 20)]
The calculation is based on the following:
R20

: Resistance at 20

°C (mΩ)

Rt

: Measured resistance (m

Ω)

T

: Temperature when the resistance is measured (

°C)

JMCIA0137GB

HBC-180

< COMPONENT DIAGNOSIS >

P0A1B-788

5. Using a megohmmeter (500 V range), measure the resistance according to the value(s) in the table

below.

NOTE:

Be sure to set the megohmmeter to 500 V when performing this test. Using a setting higher than 500 V

can result in damage to the component being inspected.

OK or NG

OK

>> GO TO 7.

NG

>> Replace hybrid transaxle (See 

TM-36, "Removal and Installation"

).

7.

INSPECT HYBRID TRANSAXLE (MG2)

CAUTION:

Be sure to wear insulated gloves.

1. Check that the service plug grip is not installed.

2. Disconnect the generator cable and motor cable from the inverter with converter assembly (See 

HBC-

638, "Removal and Installation"

).

3. Using a milliohmmeter, measure the resistance according to the

value(s) in the table below. (Check MG2 for an interphase

short.)

NOTE:

If the MG2 temperature is high, the resistance varies greatly.

Therefore, measure the resistance at least 8 hours after the

vehicle is stopped.

NOTE:

To correct the variation of the measured resistance due to temperature, use the following formula to calcu-

late the resistance at 20

°C.

4. Using a megohmmeter (500 V range), measure the resistance according to the value(s) in the table

below.

NOTE:

Be sure to set the megohmmeter to 500 V when performing this test. Using a setting higher than 500 V

can result in damage to the component being inspected.

OK or NG

OK

>> Replace inverter with converter assembly (See 

HBC-638, "Removal and Installation"

).

Terminal

Ground

Resistance

U

Body ground and 
shielded wire ground

20 M

Ω or higher

V

W

Terminal

Terminal

Resistance

U

V

69.5 to 76.5 m

Ω

V

W

66.5 to 73.5 m

Ω

W

U

66.5 to 73.5 m

Ω

R20 = Rt / [1 + 0.00393 X (T - 20)]
The calculation is based on the following:
R20

: Resistance at 20

°C (mΩ)

Rt

: Measured resistance (m

Ω)

T

: Temperature when the resistance is measured (

°C)

Terminal

Ground

Resistance

U

Body ground and 
shielded wire ground

20 M

Ω or higher

V

W

JMCIA0138GB