Nissan Altima HL32 Hybrid. Manual - part 545

P0A1F-123

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COMPONENT DIAGNOSIS

P0A1F-123

Description

INFOID:0000000004212249

The hybrid vehicle control ECU alerts the driver and performs fail safe control based on error signals sent from

the battery smart unit.

DTC Logic

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DTC DETECTION LOGIC

If the battery smart unit detects an internal malfunction in the unit itself, the hybrid vehicle control ECU will illu-

minate the MIL and set a DTC.

Diagnosis Procedure

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1.

PRECONDITIONING

• Before inspecting the high-voltage system, 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-volt-

age 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.

• After completing repairs, restart the system [turn ignition switch ON (READY)] and recheck for DTCs.

>> GO TO 2.

2.

CHECK AUXILIARY BATTERY

1. Turn ignition switch OFF.

2. Measure the voltage between the terminals of the auxiliary battery.

OK or NG

OK

>> GO TO 3.

NG

>> Charge or replace auxiliary battery.

3.

CHECK HARNESS AND CONNECTOR (IGCT VOLTAGE)

CAUTION:

Be sure to wear insulated gloves.

1. Remove the service plug grip (Refer to 

HBB-92, "Precautions for Inspecting the Hybrid Control System"

).

2. Remove the battery smart unit (Refer to 

HBB-101, "Removal and Installation"

).

NOTE:

Do not disconnect the battery smart unit harness connectors.

3. Disconnect battery smart unit harness connector B130.

4. Turn ignition switch ON.

DTC No.

INF code

Trouble diagnosis name

DTC detecting condition

Possible cause

P0A1F

123

Battery energy control module

Reception of an error signal from 
the battery smart unit

• Battery smart unit
• Auxiliary battery
• Wire harness or connector
• Fuse (No. 69)

Standard voltage: 11 to 14 V

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P0A1F-123

5. Measure the voltage according to the value(s) in the table below.

OK or NG

OK

>> Replace battery smart unit. (Refer to 

HBB-101,

"Removal and Installation"

).

NG

>> GO TO 4.

4.

CHECK FUSE

1. Turn ignition switch OFF.

2. Remove 10A fuse (No. 69) from the high voltage fuse and fusible link box.

3. Measure the resistance of the fuse.

OK or NG

OK

>> GO TO 5.

NG

>> Replace fuse.

5.

CHECK HARNESS AND CONNECTOR (BATTERY SMART UNIT - IGCT RELAY)

CAUTION:

Be sure to wear insulated gloves.

1. Install the 10A fuse (No. 69) to the high voltage fuse and fusible link box.

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

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

Check for open

OK or NG

OK

>> Check and repair power source circuit.

NG

>> Repair or replace harness or connector.

Battery Smart Unit (A)

Battery Smart Unit (A)

Voltage

Connector

Terminal

Connector

Terminal

B130

1 (IGCT [LH6])

B130

10 (GND)

9 to 14 V

JMCIA0249ZZ

Standard resistance: Below 1

Ω

Battery Smart Unit

High voltage fuse and fusible link 

box

Resistance

Connector

Terminal

Connector

Terminal

B130

1 (IGCT [LH6])

—

5

Below 1

Ω

P0A7F-123

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P0A7F-123

Description

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The battery smart unit and the hybrid vehicle control ECU calculate the SOC (state of charge) of the HV bat-

tery based on the accumulated amperage in the HV battery. The battery smart unit sends a signal indicating

the condition of the HV battery to the hybrid vehicle control ECU. The hybrid vehicle control ECU then calcu-

lates the SOC based on this information and controls HV battery charge and discharge according to the driv-

ing conditions.

DTC Logic

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DTC DETECTION LOGIC

The battery smart unit calculates the resistance of the HV battery using amperage and voltage, and uses this

resistance to determine the extent of deterioration of the HV battery. If the battery smart unit detects that the

resistance of the HV battery has exceeded the standard, it determines that a malfunction has occurred. In

addition, the battery smart unit monitors the SOC, and if the difference between the maximum and minimum

SOC values exceeds the standard, it determines that a malfunction has occurred. When either of the DTC

detection conditions is met, the hybrid vehicle control ECU will illuminate the MIL and set a DTC.

NOTE:

P0A7F cannot be set unless the vehicle is driven for approximately 10 minutes after clearing the DTCs.

(For 2 trip detection, turn ignition switch OFF and perform a road test again after the first road test.)

Diagnosis Procedure

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1.

CHECK FOR DTC (DTC P0A1F-123 IS OUTPUT)

1. Turn ignition switch ON.

2. Check DTC.
Is DTC P0A1F-123 detected?

YES

>> Go to Diagnosis Procedure relevant to output DTC.

NO

>> GO TO 2.

2.

READ VALUE ON CONSULT-III

1. Ensure the safety of the areas in front and at the back of the vehicle.

2. Turn ignition switch ON (READY).

3. Select “V1 BATT BLOCK” to “V17 BATT BLOCK” in “DATA MONITOR” mode with CONSULT-III.

JMCIA0085GB

DTC No.

INF code

Trouble diagnosis name

DTC detecting condition

Possible cause

P0A7F

123

Hybrid battery pack deterioration

• Internal resistance of HV battery is higher 

than the standard (1 trip detection)

• Difference in the capacity between battery  

block is larger than the standard (2 trip de-
tection)

• HV  battery
• Battery smart unit

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P0A7F-123

4. Fully warm up the engine and turn the air conditioning off.

5. Firmly depress the brake pedal with your left foot.

6. Move the shift lever to the D position.

7. Record each monitor item (V1 to V17 BATT BLOCK) while fully depressing the accelerator pedal.

8. Compare the battery block voltages (V1 to V17 BATT BLOCK) between the even and odd number groups

in each combination shown in the table below.

9. Check the voltage difference in the all 9 combinations.

YES or NO

YES

>> Replace battery smart unit (Refer to 

HBB-101, "Removal and Installation"

).

NO

>> Replace HV battery (Refer to 

HBB-97, "Removal and Installation"

).

Even number group

Odd number group

Battery block voltages to be compared

V1 BATT BLOCK

V2 BATT BLOCK

VB1 

←→ VB2

V3 BATT BLOCK

V4 BATT BLOCK

VB2 

←→ VB4

V5 BATT BLOCK

V6 BATT BLOCK

VB5 

←→ VB6

V7 BATT BLOCK

V8 BATT BLOCK

VB7 

←→ VB8

V9 BATT BLOCK

V10 BATT BLOCK

VB9 

←→ VB10

V11 BATT BLOCK

V12 BATT BLOCK

VB11 

←→ VB12

V13 BATT BLOCK

V14 BATT BLOCK

VB13 

←→ VB14

V15 BATT BLOCK

V16 BATT BLOCK

VB15 

←→ VB16

V17 BATT BLOCK

V16 BATT BLOCK

VB17 

←→ VB16

The difference in voltage of all combinations is 0.3 V or more.