2007 INFINITI QX56 engine

EC-486
< SERVICE INFORMATION >
DTC P1550 BATTERY CURRENT SENSOR
*: Before measuring the terminal voltage, confirm that the battery is fully charged. Refer to SC-4, "How to Handle Battery".
Diagnosis ProcedureINFOID:0000000003532016
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten ground screws on the body.
Refer to EC-143, "
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 (1) harness connector.
2. Turn ignition switch ON.
TER-
MI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
49 R/YSensor power supply
(Battery current sensor)[Ignition switch: ON]Approximately 5V
67 BSensor ground
(Battery current sensor)[Engine is running]
•Warm-up condition
• Idle speedApproximately 0V
71 R Battery current sensor[Engine is running]
• Battery: Fully charged*
• Idle speedApproximately 2.6 - 3.5V
BBIA0354E
BBIA0744E

DTC P1551, P1552 BATTERY CURRENT SENSOR
EC-489
< SERVICE INFORMATION >
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DTC P1551, P1552 BATTERY CURRENT SENSOR
Component DescriptionINFOID:0000000003532018
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 (1) is installed to the battery cable at the negative termi-
nal. The sensor measures the charging/discharging current of the
battery. 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 SC section.
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.
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000003532019
Specification data are reference values.
*: Before measuring the terminal voltage, confirm that the battery is fully charged. Refer to SC-4, "How to Handle Battery".
On Board Diagnosis LogicINFOID:0000000003532020
The MIL will not light up for these self-diagnoses.
NOTE:
If DTC P1551 or P1552 is displayed with DTC P0643, first perform the trouble diagnosis for DTC P0643.
Refer to EC-447
.
DTC Confirmation ProcedureINFOID:0000000003532021
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 8V with ignition
switch ON
WITH CONSULT-II
1. Turn ignition switch ON.
BBIA0744E
MONITOR ITEM CONDITION SPECIFICATION
BAT CUR SEN• Engine speed: Idle
• Battery: Fully charged*
• Selector lever: P or N
• Air conditioner switch: OFF
•No loadApprox. 2,600 - 3,500mV
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1551
1551Battery current sensor circuit
low inputAn excessively low voltage from the sensor
is sent to ECM.• Harness or connectors
(The sensor circuit is open or shorted.)
• Battery current sensor P1552
1552Battery current sensor circuit
high inputAn excessively high voltage from the sensor
is sent to ECM.

EC-492
< SERVICE INFORMATION >
DTC P1551, P1552 BATTERY CURRENT SENSOR
*: Before measuring the terminal voltage, confirm that the battery is fully charged. Refer to SC-4, "How to Handle Battery".
Diagnosis ProcedureINFOID:0000000003532023
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten ground screws on the body.
Refer to EC-143, "
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 (1) harness connector.
2. Turn ignition switch ON.
TER-
MI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
49 R/YSensor power supply
(Battery current sensor)[Ignition switch: ON]Approximately 5V
67 BSensor ground
(Battery current sensor)[Engine is running]
•Warm-up condition
• Idle speedApproximately 0V
71 R Battery current sensor[Engine is running]
• Battery: Fully charged*
• Idle speedApproximately 2.6 - 3.5V
BBIA0354E
BBIA0744E

DTC P1553 BATTERY CURRENT SENSOR
EC-495
< SERVICE INFORMATION >
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DTC P1553 BATTERY CURRENT SENSOR
Component DescriptionINFOID:0000000003532025
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 (1) is installed to the battery cable at the negative termi-
nal. The sensor measures the charging/discharging current of the
battery. 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 SC section.
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.
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000003532026
Specification data are reference values.
*: Before measuring the terminal voltage, confirm that the battery is fully charged. Refer to SC-4, "How to Handle Battery".
On Board Diagnosis LogicINFOID:0000000003532027
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-447
.
DTC Confirmation ProcedureINFOID:0000000003532028
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 8V at idle.
WITH CONSULT-II
1. Turn ignition switch ON.
BBIA0744E
MONITOR ITEM CONDITION SPECIFICATION
BAT CUR SEN• Engine speed: Idle
• Battery: Fully charged*
• Selector lever: P or N
• Air conditioner switch: OFF
•No loadApprox. 2,600 - 3,500mV
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1553
1553Battery current sensor performanceThe 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

EC-496
< SERVICE INFORMATION >
DTC P1553 BATTERY CURRENT SENSOR
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Start engine and wait at least 10 seconds.
4. If 1st trip DTC is detected, go to EC-498, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-II” above.
SEF058Y

EC-498
< SERVICE INFORMATION >
DTC P1553 BATTERY CURRENT SENSOR
*: Before measuring the terminal voltage, confirm that the battery is fully charged. Refer to SC-4, "How to Handle Battery".
Diagnosis ProcedureINFOID:0000000003532030
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten ground screws on the body.
Refer to EC-143, "
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 (1) harness connector.
2. Turn ignition switch ON.
TER-
MI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
49 R/YSensor power supply
(Battery current sensor)[Ignition switch: ON]Approximately 5V
67 BSensor ground
(Battery current sensor)[Engine is running]
•Warm-up condition
• Idle speedApproximately 0V
71 R Battery current sensor[Engine is running]
• Battery: Fully charged*
• Idle speedApproximately 2.6 - 3.5V
BBIA0354E
BBIA0744E

DTC P1554 BATTERY CURRENT SENSOR
EC-501
< SERVICE INFORMATION >
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EC
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DTC P1554 BATTERY CURRENT SENSOR
Component DescriptionINFOID:0000000003532032
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 (1) is installed to the battery cable at the negative termi-
nal. The sensor measures the charging/discharging current of the
battery. 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 SC section.
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.
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000003532033
Specification data are reference values.
*: Before measuring the terminal voltage, confirm that the battery is fully charged. Refer to SC-4, "How to Handle Battery".
On Board Diagnosis LogicINFOID:0000000003532034
The MIL will not light up for this self-diagnosis.
NOTE:
If DTC P1554 is displayed with DTC P0643, first perform the trouble diagnosis for DTC P0643. Refer to
EC-447
.
Overall Function CheckINFOID:0000000003532035
Use this procedure to check the overall function of the battery current sensor circuit. During this check, a 1st
trip DTC might not be confirmed.
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.
WITH CONSULT-II
1. Start engine and let it idle.
BBIA0744E
MONITOR ITEM CONDITION SPECIFICATION
BAT CUR SEN• Engine speed: Idle
• Battery: Fully charged*
• Selector lever: P or N
• Air conditioner switch: OFF
•No loadApprox. 2,600 - 3,500mV
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1554
1554Battery current sensor performanceThe output voltage of the battery current
sensor is lower than the specified value
while the battery voltage is high enough.• Harness or connectors
(The sensor circuit is open or shorted.)
• Battery current sensor

EC-502
< SERVICE INFORMATION >
DTC P1554 BATTERY CURRENT SENSOR
2. Select “BAT CUR SEN” in “DATA MONITOR” mode with CON-
SULT-II.
3. Check “BAT CUR SEN” indication for 10 seconds.
“BAT CUR SEN” should be above 2,300mV at least once.
4. If NG, go to EC-504, "
Diagnosis Procedure".
WITH GST
1. Start engine and let it idle.
2. Check voltage between ECM terminal 71 (battery current sensor
signal) and ground for 10 seconds.
The voltage should be above 2.3V at least once.
3. If NG, go to EC-504, "
Diagnosis Procedure".
PBIB2615E
PBIB2616E