2009 INFINITI QX56 battery

EC-318
< COMPONENT DIAGNOSIS >[VK56DE]
P1553 BATTERY CURRENT SENSOR
5.DETECT MALFUNCTIONING PART
Check the following.
 Harness connectors E5, F14
 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.
6.CHECK BATTERY CURRENT SENSOR INPUT SI GNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between battery curr ent sensor terminal 3 and ECM terminal 71.
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 E2, F32
 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.
8.CHECK BATTERY CURRENT SENSOR
Refer to EC-318, "Component Inspection"
.
OK or NG
OK >> GO TO 9.
NG >> Replace battery negative cable assembly.
9.CHECK INTERMITTENT INCIDENT
Refer to GI-35, "How to Check Terminal"
and GI-38, "Intermittent Incident".
>> INSPECTION END
Component InspectionINFOID:0000000003771619
BATTERY CURRENT SENSOR
1. Reconnect harness connectors disconnected.
2. Disconnect battery negative cable (1).
3. Install jumper cable (A) between battery negative terminal and
body ground.
4. Turn ignition switch ON. Continuity should exist.
BBIA0745E
Revision: December 20092009 QX56

P1553 BATTERY CURRENT SENSOREC-319
< COMPONENT DIAGNOSIS > [VK56DE]
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5. Check voltage between ECM terminal 71 (battery current sensor
signal) and ground.
6. If NG, replace battery negative cable assembly. Voltage: Approximately 2.5V
PBIB2617E
Revision: December 20092009 QX56

EC-320
< COMPONENT DIAGNOSIS >[VK56DE]
P1554 BATTERY CURRENT SENSOR
P1554 BATTERY CURRENT SENSOR
Component DescriptionINFOID:0000000003771620
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
CHG-7, "System
Description".
: Vehicle front
CAUTION:
Do not connect the electrical compon ent or the ground wire directly to the battery terminal. The con-
nection causes the malfunction of th e power generation voltage variable control, and then the battery
discharge may occur.
On Board Diagn osis LogicINFOID:0000000003771621
The MIL will not light up for this self-diagnosis.
NOTE:
If DTC P1554 is displayed with DTC P0643, first pe rform the trouble diagnosis for DTC P0643. Refer to
EC-285, "On Board Diagnosis Logic"
.
Overall Function CheckINFOID:0000000003771622
Use this procedure to check the overall function of the bat tery current sensor circuit. During this check, a 1st
trip DTC might not be confirmed.
TESTING CONDITION:
 Before performing the following procedure, confirm th at battery voltage is more than 12.8V at idle.
 Before performing the following procedure, confi rm that all load switches and A/C switch are turned
OFF.
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.
4. If NG, go to EC-321, "Diagnosis Procedure"
.
WITH GST
1. Start engine and let it idle.
BBIA0744E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1554
1554 Battery current sensor performance The 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
Revision: December 20092009 QX56

P1554 BATTERY CURRENT SENSOREC-321
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2. Check voltage between ECM terminal 71 (battery current sensor
signal) and ground for 10 seconds.
The voltage should be ab ove 2.3V at least once.
3. If NG, go to EC-321, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771623
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten ground screws on the body. Refer to EC-85, "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. : Vehicle front
3. Check voltage between battery current sensor terminal 1 and ground with CONSULT-III or tester.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
3.DETECT MALFUNCTIONING PART
PBIB2616E
BBIA0354E
BBIA0744E
Voltage: Approximately 5V
PBIA9891J
Revision: December 20092009 QX56

EC-322
< COMPONENT DIAGNOSIS >[VK56DE]
P1554 BATTERY CURRENT SENSOR
Check the following.
 Harness connectors E5, F14
 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.
4.CHECK BATTERY CURRENT SENSOR GRO UND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between battery curr ent sensor terminal 2 and ECM terminal 67.
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.
5.DETECT MALFUNCTIONING PART
Check the following.
 Harness connectors E5, F14
 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.
6.CHECK BATTERY CURRENT SENSOR INPUT SI GNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between battery curr ent sensor terminal 3 and ECM terminal 71.
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 E2, F32
 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.
8.CHECK BATTERY CURRENT SENSOR
Refer to EC-322, "Component Inspection"
.
OK or NG
OK >> GO TO 9.
NG >> Replace battery negative cable assembly.
9.CHECK INTERMITTENT INCIDENT
Refer to GI-35, "How to Check Terminal"
and GI-38, "Intermittent Incident".
>> INSPECTION END
Component InspectionINFOID:0000000003771624
BATTERY CURRENT SENSOR
Continuity should exist.
Continuity should exist.
Revision: December 20092009 QX56

P1554 BATTERY CURRENT SENSOREC-323
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1. Reconnect harness connectors disconnected.
2. Disconnect battery negative cable (1).
3. Install jumper cable (A) between battery negative terminal and
body ground.
4. Turn ignition switch ON.
5. Check voltage between ECM terminal 71 (battery current sensor signal) and ground.
6. If NG, replace battery negative cable assembly.
BBIA0745E
Voltage: Approximately 2.5V
PBIB2617E
Revision: December 20092009 QX56

EC-334
< COMPONENT DIAGNOSIS >[VK56DE]
P1572 ICC BRAKE SWITCH
5. Check 1st trip DTC.
6. If 1st trip DTC is detected, go to
EC-334, "Diagnosis Procedure"
.
If 1st trip DTC is not detec ted, go to the following step.
7. Drive the vehicle for at least 5 consec utive seconds under the following conditions.
8. Check 1st trip DTC.
9. If 1st trip DTC is detected, go to EC-334, "Diagnosis Procedure"
.
Diagnosis ProcedureINFOID:0000000003771641
1.CHECK OVERALL FUNCTION-I
With CONSULT-IIl
1. Turn ignition switch ON.
2. Select “BRAKE SW1” in “DAT A MONITOR” mode with CONSULT-IIl.
3. Check “BRAKE SW1” indication under the following conditions.
Without CONSULT-IIl
1. Turn ignition switch ON.
2. Check voltage between ECM terminal 108 and ground under the following conditions.
OK or NG
OK >> GO TO 2.
NG >> GO TO 3.
2.CHECK OVERALL FUNCTION-II
With CONSULT-IIl
Check “BRAKE SW2” indication in “DATA MONITOR” mode.
Without CONSULT-IIl
VHCL SPEED SE More than 30 km/h (19 MPH)
Selector lever Suitable position
VHCL SPEED SE More than 30 km/h (19 MPH)
Selector lever Suitable position
Driving location Depress the brake pedal for more than
five seconds so as not to come off from
the above-mentioned vehicle speed.
CONDITION INDICATION
Brake pedal: Slightly depressed OFF
Brake pedal: Fully released ON
CONDITION VOLTAGE
Brake pedal: Slightly depressed Approximately 0V
Brake pedal: Fully released Battery voltage
MBIB0061E
CONDITION INDICATION
Brake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
Revision: December 20092009 QX56

P1572 ICC BRAKE SWITCHEC-335
< COMPONENT DIAGNOSIS > [VK56DE]
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Check voltage between ECM terminal 101 and ground under the fol-
lowing conditions.
OK or NG
OK >> GO TO 14.
NG >> GO TO 7.
3.CHECK ICC BRAKE SWITCH POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ICC brake switch harness connector.
3. Turn ignition switch ON.
4. Check voltage between ICC brake switch terminal 1 and ground with CONSULT-lll or tester.
OK or NG
OK >> GO TO 5.
NG >> GO TO 4.
4.DETECT MALFUNCTIONING PART
Check the following.
 Harness connectors M31, E152
 Fuse block (J/B) connector M4
 10A fuse
 Harness for open or short between ICC brake switch and fuse
>> Repair open circuit or short to ground or short to power in harness or connectors.
5.CHECK ICC BRAKE SWITCH INPUT SIGN AL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between ICC brake switch terminal 2 and ECM terminal 108. Refer Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 6.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
6.CHECK ICC BRAKE SWITCH
Refer to EC-337, "Component Inspection"
.
OK or NG
OK >> GO TO 14.
NG >> Replace ICC brake switch.
7.CHECK DTC WITH ICC UNIT
CONDITION VOLTAGE
Brake pedal: Fully released Approximately 0V
Brake pedal: Slightly depressed Battery voltage
PBIB1537E
Voltage: Battery voltage
BBIA0470E
Continuity should exist.
Revision: December 20092009 QX56