Nissan Frontier. Manual - part 451

P1551, P1552 BATTERY CURRENT SENSOR

EC-375

< DTC/CIRCUIT DIAGNOSIS >

[QR25DE]

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P1551, P1552 BATTERY CURRENT SENSOR

Component Description

INFOID:0000000009481063

The power generation voltage variable control enables fuel con-

sumption to be decreased by reducing the engine load which is

caused by the power generation of the generator. The battery cur-

rent 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 per-

forming the power generation voltage variable control, ECM calcu-

lates the target power generation voltage based on the sensor

signal. And ECM sends the calculated value as the power genera-

tion command value to IPDM E/R. For the details of the power gen-

eration voltage variable control, refer to 

CHG-9, "System

Description"

.

CAUTION:

Never 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.

On Board Diagnosis Logic

INFOID:0000000009481064

The MIL will not light up for these diagnosis.

NOTE:

If DTC P1551 or P1552 is displayed with DTC P0643, first perform the trouble diagnosis for DTC P0643.

Refer to 

EC-350

.

DTC Confirmation Procedure

INFOID:0000000009481065

If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at

least 10 seconds before conducting the next test.

TESTING CONDITION:

Before performing the following procedure, confirm that battery voltage is more than 10V with ignition

switch ON

 WITH CONSULT

1. Turn ignition switch ON and wait at least 10 seconds.
2. Check 1st trip DTC.
3. If 1st trip DTC is detected, go to 

EC-375, "Diagnosis Procedure"

.

 WITH GST

Follow the procedure “WITH CONSULT” above.

Diagnosis Procedure

INFOID:0000000009481066

1.

CHECK GROUND CONNECTIONS

1. Turn ignition switch OFF.

2. Loosen and retighten two ground screws on the body.

BBIA0630E

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P1551
1551

Battery current sensor circuit 
low input

An excessively low voltage from the 
sensor is sent to ECM.

• Harness or connectors

(The sensor circuit is open or shorted.)

• Battery current sensor

P1552
1552

Battery current sensor circuit 
high input

An excessively high voltage from the 
sensor is sent to ECM.

EC-376

< DTC/CIRCUIT DIAGNOSIS >

[QR25DE]

P1551, P1552 BATTERY CURRENT SENSOR

Refer to 

EC-149, "Ground Inspection"

.

OK or NG

OK

>> GO TO 2.

NG

>> Repair or replace ground connections.

2.

CHECK BATTERY CURRENT SENSOR POWER SUPPLY CIRCUIT

1. Disconnect battery current sensor harness connector.

2. Turn ignition switch ON.

3. Check voltage between battery current sensor terminal 1 and

ground with CONSULT or tester.

OK or NG

OK

>> GO TO 4.

NG

>> GO TO 3.

3.

DETECT MALFUNCTIONING PART

Check the following.

• Harness connectors E5, F14

• Harness for open or short between battery current sensor and ECM

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

4.

CHECK BATTERY CURRENT SENSOR GROUND CIRCUIT FOR OPEN AND SHORT

1. Turn ignition switch OFF.

2. Disconnect ECM harness connector.

3. Check harness continuity between battery current sensor terminal 2 and ECM terminal 44.

Refer to Wiring Diagram.

4. Also check harness for short to ground and short to power.
OK or NG

OK

>> GO TO 6.

NG

>> GO TO 5.

BBIA0614E

BBIA0630E

Voltage: Approximately 5V

PBIA9891J

Continuity should exist.

P1551, P1552 BATTERY CURRENT SENSOR

EC-377

< DTC/CIRCUIT DIAGNOSIS >

[QR25DE]

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5.

DETECT MALFUNCTIONING PART

Check the following.

• Harness connectors E5, F14

• Harness for open or short between battery current sensor and ECM

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

6.

CHECK BATTERY CURRENT SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1. Check harness continuity between battery current sensor terminal 3 and ECM terminal 42.

Refer to Wiring Diagram.

2. Also check harness for short to ground and short to power.
OK or NG

OK

>> GO TO 8.

NG

>> GO TO 7.

7.

DETECT MALFUNCTIONING PART

Check the following.

• Harness connectors E5, F14

• Harness for open or short between battery current sensor and ECM

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

8.

CHECK BATTERY CURRENT SENSOR

Refer to 

EC-377, "Component Inspection"

.

OK or NG

OK

>> GO TO 9.

NG

>> Replace battery negative cable assembly.

9.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-42, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection

INFOID:0000000009481067

BATTERY CURRENT SENSOR

1. Reconnect harness connectors disconnected.
2. Disconnect battery negative cable.
3. Install jumper cable between battery negative terminal and body

ground.

4. Turn ignition switch ON.
5. Check voltage between ECM terminal 42 (battery current sensor

signal) and ground.

6. If NG, replace battery negative cable assembly.

Continuity should exist.

Voltage: Approximately 2.5V

BBIA0631E

EC-378

< DTC/CIRCUIT DIAGNOSIS >

[QR25DE]

P1553 BATTERY CURRENT SENSOR

P1553 BATTERY CURRENT SENSOR

Component Description

INFOID:0000000009481068

The power generation voltage variable control enables fuel con-

sumption to be decreased by reducing the engine load which is

caused by the power generation of the generator. The battery cur-

rent 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 per-

forming the power generation voltage variable control, ECM calcu-

lates the target power generation voltage based on the sensor

signal. And ECM sends the calculated value as the power genera-

tion command value to IPDM E/R. For the details of the power gen-

eration voltage variable control, refer to 

CHG-9, "System

Description"

.

CAUTION:

Never 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.

On Board Diagnosis Logic

INFOID:0000000009481069

The MIL will not light up for this self-diagnosis.

NOTE:

If DTC P1553 is displayed with DTC P0643, first perform the trouble diagnosis for DTC P0643. Refer to

EC-350

.

DTC Confirmation Procedure

INFOID:0000000009481070

If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at

least 10 seconds before conducting the next test.

TESTING CONDITION:

Before performing the following procedure, confirm that battery voltage is more than 10V at idle.

 WITH CONSULT

1. Start engine and wait at least 10 seconds.
2. Check 1st trip DTC.
3. If 1st trip DTC is detected, go to 

EC-378, "Diagnosis Procedure"

.

 WITH GST

Follow the procedure “WITH CONSULT” above.

Diagnosis Procedure

INFOID:0000000009481071

1.

CHECK GROUND CONNECTIONS

1. Turn ignition switch OFF.

2. Loosen and retighten two ground screws on the body.

BBIA0630E

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P1553
1553

Battery current sensor 
performance

The signal voltage transmitted from the 
sensor to ECM is higher than the amount of 
the maximum power generation.

• Harness or connectors

(The sensor circuit is open or shorted.)

• Battery current sensor