Infiniti G37 Coupe. Manual - part 559

P1554 BATTERY CURRENT SENSOR

EC-417

< COMPONENT DIAGNOSIS >

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P1554 BATTERY CURRENT SENSOR

Description

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The power generation voltage variable control enables fuel consumption to be decreased by reducing the
engine load which is caused by the power generation of the generator. The battery current sensor is installed
to the battery cable at the negative terminal. The sensor measures the charging/discharging current of the bat-
tery. Based on the sensor signal, ECM judges whether or not the power generation voltage variable control is
performed. When performing the power generation voltage variable control, ECM calculates the target power
generation voltage based on the sensor signal. And ECM sends the calculated value as the power generation
command value to IPDM E/R. For the details of the power generation voltage variable control, refer to 

CHG-8,

"System Description"

.

CAUTION:

Do not connect the electrical component or the ground wire directly to the battery terminal. The con-
nection causes the malfunction of the power generation voltage variable control, and then the battery
discharge may occur.

DTC Logic

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DTC DETECTION LOGIC

NOTE:
If DTC P1554 is displayed with DTC P0643, first perform the trouble diagnosis for DTC P0643. Refer to 

EC-

358, "DTC Logic"

.

DTC CONFIRMATION PROCEDURE

1.

PERFORM COMPONENT FUNCTION CHECK

Perform component function check. Refer to 

EC-417, "Component Function Check"

.

NOTE:
Use component function check to check the overall function of the battery current sensor circuit. During this
check, a 1st trip DTC might not be confirmed.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Go to 

EC-418, "Diagnosis Procedure"

.

Component Function Check

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1.

PRECONDITIONING

TESTING CONDITION:
• Before performing the following procedure, confirm that battery voltage is more than 12.8V at idle.
• Before performing the following procedure, confirm that all load switches and A/C switch are turned

OFF.

>> GO TO 2.

2.

PERFORM COMPONENT FUNCTION CHECK

With CONSULT-III

1.

Start engine and let it idle.

2.

Select “BAT CUR SEN” in “DATA MONITOR” mode with CONSULT-III.

3.

Check “BAT CUR SEN” indication for 10 seconds.
“BAT CUR SEN” should be above 2,300mV at least once.

Without CONSULT-III

1.

Start engine and let it idle.

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P1554

Battery current sensor perfor-
mance

The output voltage of the battery current 
sensor is lower than the specified value 
while the battery voltage is high enough.

• Harness or connectors

(Battery current sensor circuit is open 
or shorted.)

• Battery current sensor

EC-418

< COMPONENT DIAGNOSIS >

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P1554 BATTERY CURRENT SENSOR

2.

Check the voltage between ECM harness connector and ground.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Go to 

EC-418, "Diagnosis Procedure"

Diagnosis Procedure

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1.

CHECK GROUND CONNECTION

1.

Turn ignition switch OFF.

2.

Check ground connection M95. Refer to Ground Inspection in 

GI-41, "Circuit Inspection"

.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Repair or replace ground connection.

2.

CHECK BATTERY CURRENT SENSOR POWER SUPPLY CIRCUIT-I

1.

Disconnect battery current sensor harness connector.

2.

Turn ignition switch ON.

3.

Check the voltage between battery current sensor harness connector and ground.

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> GO TO 3.

3.

CHECK BATTERY CURRENT SENSOR POWER SUPPLY CIRCUIT-II

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Check the continuity between battery current sensor harness connector and ECM harness connector.

4.

Also check harness for short to ground and short to power.

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> GO TO 4.

4.

DETECT MALFUNCTIONING PART

Check the following.
• Harness connectors F1, E3
• Harness for open or short between battery current sensor and ECM

>> Repair open circuit or short to ground or short to power in harness connectors.

5.

CHECK BATTERY CURRENT SENSOR GROUND CIRCUIT FOR OPEN AND SHORT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

ECM

Ground

Voltage

Connector

Terminal

F102

91

(Battery current sensor signal)

Ground

Above 2.3V at least once

Battery current sensor

Ground

Voltage

Connector

Terminal

E21

1

Ground

Approx. 5V

Battery current sensor

ECM

Continuity

Connector

Terminal

Connector

Terminal

E21

1

F102

64

Existed

P1554 BATTERY CURRENT SENSOR

EC-419

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3.

Check the continuity between battery current sensor harness connector and ECM harness connector.

4.

Also check harness for short to ground and short to power.

Is the inspection result normal?

YES

>> GO TO 7.

NO

>> GO TO 6.

6.

DETECT MALFUNCTIONING PART

Check the following.
• Harness connectors F1, E3
• Harness for open or short between battery current sensor and ECM

>> Repair open circuit or short to ground or short to power in harness or connectors.

7.

CHECK BATTERY CURRENT SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.

Check the continuity between battery current sensor harness connector and ECM harness connector.

2.

Also check harness for short to ground and short to power.

Is the inspection result normal?

YES

>> GO TO 9.

NO

>> GO TO 8.

8.

DETECT MALFUNCTIONING PART

Check the following.
• Harness connectors F1, E3
• Harness for open or short between battery current sensor and ECM

>> Repair open circuit or short to ground or short to power in harness or connectors.

9.

CHECK BATTERY CURRENT SENSOR

Refer to 

EC-419, "Component Inspection"

.

Is the inspection result normal?

YES

>> GO TO 10.

NO

>> Replace battery negative cable assembly.

10.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-38, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection

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1.

CHECK BATTERY CURRENT SENSOR

1.

Turn ignition switch OFF.

2.

Reconnect harness connectors disconnected.

Battery current sensor

ECM

Continuity

Connector

Terminal

Connector

Terminal

E21

2

F102

95

Existed

Battery current sensor

ECM

Continuity

Connector

Terminal

Connector

Terminal

E21

3

F102

91

Existed

EC-420

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P1554 BATTERY CURRENT SENSOR

3.

Disconnect battery negative cable (1).

4.

Install jumper cable (A) between battery negative terminal and
body ground.

5.

Turn ignition switch ON.

6.

Check the voltage between ECM harness connector and
ground.

Before measuring the terminal voltage, confirm that the battery is fully charged. Refer to 

PG-3, "How to Handle Battery"

.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace battery negative cable assembly.

: To body ground

ECM

Ground

Voltage

Connector

Terminal

F102

91

(Battery current sensor signal)

Ground

Approx. 2.5V

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