light INFINITI QX56 2007 Factory Service Manual

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.

DTC P1553 BATTERY CURRENT SENSOR
EC-495
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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

DTC P1554 BATTERY CURRENT SENSOR
EC-501
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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

DTC P1564 ICC STEERING SWITCH
EC-507
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DTC P1564 ICC STEERING SWITCH
Component DescriptionINFOID:0000000003532039
ICC steering switch has variant values of electrical resistance for each button. ECM reads voltage variation of
switch, and determines which button is operated.
Refer to EC-30, "
System Description" for the ICC function.
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000003532040
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000003532041
This self-diagnosis has the one trip detection logic.
The MIL will not light up for this self-diagnosis.
NOTE:
If DTC P1564 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605. Refer to
EC-444
.
DTC Confirmation ProcedureINFOID:0000000003532042
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
PBIB2640E
MONITOR ITEM CONDITION SPECIFICATION
MAIN SW • Ignition switch: ONMAIN switch: Pressed ON
MAIN switch: Released OFF
CANCEL SW • Ignition switch: ONCANCEL switch: Pressed ON
CANCEL switch: Released OFF
RESUME/ACC SW • Ignition switch: ONRESUME/ACCELERATE switch:
PressedON
RESUME/ACCELERATE switch: Re-
leasedOFF
SET SW • Ignition switch: ONSET/COAST switch: Pressed ON
SET/COAST switch: Released OFF
DIST SW • Ignition switch: ONDISTANCE switch: Pressed ON
DISTANCE switch: Released OFF
DTC No.Trouble diagnosis
nameDTC detecting condition Possible cause
P1564
1564ICC steering switch• An excessively high voltage signal from the
ICC steering switch is sent to ECM.
• ECM detects that input signal from the ICC
steering switch is out of the specified range.
• ECM detects that the ICC steering switch is
stuck ON.• Harness or connectors
(The switch circuit is open or shorted.)
• ICC steering switch
• Combination switch (spiral cable)
•ECM

DTC P1564 ASCD STEERING SWITCH
EC-513
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DTC P1564 ASCD STEERING SWITCH
Component DescriptionINFOID:0000000003532046
ASCD steering switch has variant values of electrical resistance for each button. ECM reads voltage variation
of switch, and determines which button is operated.
Refer to EC-30
for the ASCD function.
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000003532047
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000003532048
•This self-diagnosis has the one trip detection logic.
•The MIL will not light up for this self-diagnosis.
NOTE:
If DTC P1564 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605. Refer to
EC-444
.
DTC Confirmation ProcedureINFOID:0000000003532049
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
WITH CONSULT-II
1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Wait at least 10 seconds.
PBIB2640E
MONITOR ITEM CONDITION SPECIFICATION
MAIN SW • Ignition switch: ONMAIN switch: Pressed ON
MAIN switch: Released OFF
CANCEL SW • Ignition switch: ONCANCEL switch: Pressed ON
CANCEL switch: Released OFF
RESUME/ACC SW • Ignition switch: ONRESUME/ACCELERATE switch: Pressed ON
RESUME/ACCELERATE switch: Released OFF
SET SW • Ignition switch: ONSET/COAST switch: Pressed ON
SET/COAST switch: Released OFF
DTC No. Trouble Diagnosis Name DTC Detecting Condition Possible Cause
P1564
1564ASCD steering switch• An excessively high voltage signal from the ASCD
steering switch is sent to ECM.
• ECM detects that input signal from the ASCD steer-
ing switch is out of the specified range.
• ECM detects that the ASCD steering switch is stuck
ON.• Harness or connectors
(The switch circuit is open or
shorted.)
• ASCD steering switch
• Combination meter (spiral cable)
•ECM

DTC P1568 ICC FUNCTION
EC-519
< SERVICE INFORMATION >
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DTC P1568 ICC FUNCTION
On Board Diagnosis LogicINFOID:0000000003532053
•This self-diagnosis has the one trip detection logic.
•The MIL will not light up for this self-diagnosis.
NOTE:
•If DTC P1568 is displayed with DTC U1000, U1001, first perform the trouble diagnosis for DTC U1000,
U1001. Refer to EC-145
.
•If DTC P1568 is displayed with DTC U1010, first perform the trouble diagnosis for DTC U1010. Refer
to EC-147
.
•If DTC P1568 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605. Refer
to EC-444
.
DTC Confirmation ProcedureINFOID:0000000003532054
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
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:
Step 4 may be conducted with the drive wheels lifted in the shop or by driving the vehicle. If a road test
is expected to be easier, it is unnecessary to lift the vehicle.
WITH CONSULT-II
1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Press MAIN switch on ICC steering switch.
4. Drive the vehicle at more than 40 km/h (25 MPH).
5. Press SET/COAST switch.
6. If DTC is detected, go to EC-519, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-II” above.
Diagnosis ProcedureINFOID:0000000003532055
1.REPLACE ICC UNIT
1. Replace ICC unit.
2. Perform ACS-9
.
3. Check DTC of ICC unit. Refer to ACS-34
.
>>INSPECTION END
DTC No.Trouble Diagnosis
NameDTC Detecting Condition Possible Cause
P1568
1568ICC functionECM detects a difference between signals
from ICC unit is out of specified range.• Harness or connectors
(The CAN communication line is open or
shorted.)
• ICC unit
•ECM
SEF058Y

EC-520
< SERVICE INFORMATION >
DTC P1572 ICC BRAKE SWITCH
DTC P1572 ICC BRAKE SWITCH
Component DescriptionINFOID:0000000003532056
When the brake pedal is depressed, ICC brake switch is turned OFF
and stop lamp switch is turned ON. ECM detects the state of the
brake pedal by this input of two kinds (ON/OFF signal).
Refer to ACS-6
for the ICC function.
CONSULT-II Reference Value in Data Monitor ModeINFOID:0000000003532057
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000003532058
•This diagnosis has the one trip detection logic.
•The MIL will not light up for this self-diagnosis.
NOTE:
•If DTC P1572 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605. Refer
to EC-444
.
•This self-diagnosis has the one trip detection logic. When malfunction A is detected, DTC is not
stored in ECM memory. And in that case, 1st trip DTC and 1st trip freeze frame data are displayed.
1st trip DTC is erased when ignition switch OFF. And even when malfunction A is detected in two
consecutive trips, DTC is not stored in ECM memory.
DTC Confirmation ProcedureINFOID:0000000003532059
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
• If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
BBIA0470E
MONITOR ITEM CONDITION SPECIFICATION
BRAKE SW1
(ICC brake switch)• Ignition switch: ONBrake pedal: Fully released ON
Brake pedal: Slightly depressed OFF
BRAKE SW2
(stop lamp switch)• Ignition switch: ONBrake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
DTC No.Trouble diagnosis
nameDTC detecting condition Possible cause
P1572
1572ICC brake switchA)When vehicle speed is above 30 km/h (19
MPH), ON signals from the stop lamp
switch and the ICC brake switch are sent to
ECM at the same time.• Harness or connectors
(The stop lamp switch circuit is shorted.)
• Harness or connectors
(The ICC brake switch circuit is shorted.)
• Stop lamp switch
• ICC brake switch
• ICC brake hold relay
• Incorrect stop lamp switch installation
• Incorrect ICC brake switch installation
•ECM B)ICC brake switch signal is not sent to ECM
for extremely long time while the vehicle is
driving

DTC P1572 ICC BRAKE SWITCH
EC-521
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• Procedure for malfunction B is not described here. It takes extremely long time to complete procedure for
malfunction B. By performing procedure for malfunction A, the incident that causes malfunction B can be
detected.
TESTING CONDITION:
Steps 4 and 5 may be conducted with the drive wheels lifted in the shop or by driving the vehicle. If a
road test is expected to be easier, it is unnecessary to lift the vehicle.
WITH CONSULT-II
1. Start engine (VDC switch OFF).
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Press MAIN switch and make sure that CRUISE lamp lights up.
4. Drive the vehicle for at least 5 consecutive seconds under the
following conditions.
If 1st trip DTC is detected, go to EC-523, "
Diagnosis Procedure".
If 1st trip DTC is not detected, go to the following step.
5. Drive the vehicle for at least 5 consecutive seconds under the following conditions.
6. If 1st trip DTC is detected, go to EC-523, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-II” above.
VHCL SPEED SE More than 30 km/h (19 MPH)
Selector lever Suitable position
PBIB2386E
VHCL SPEED SE More than 30 km/h (19 MPH)
Selector lever Suitable position
Driving locationDepress the brake pedal for more than
five seconds so as not to come off from
the above-mentioned vehicle speed.

DTC P1572 ICC BRAKE SWITCH
EC-523
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Diagnosis ProcedureINFOID:0000000003532061
1.CHECK OVERALL FUNCTION-I
With CONSULT-II
1. Turn ignition switch ON.
2. Select “BRAKE SW1” in “DATA MONITOR” mode with CON-
SULT-II.
3. Check “BRAKE SW1” indication under the following conditions.
Without CONSULT-II
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-II
Check “BRAKE SW2” indication in “DATA MONITOR” mode.
TER-
MI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
101 R/W Stop lamp switch[Ignition switch: OFF]
• Brake pedal: Fully releasedApproximately 0V
[Ignition switch: OFF]
• Brake pedal: Slightly depressedBATTERY VOLTAGE
(11 - 14V)
108 BR/W ICC brake switch[Ignition switch: ON]
• Brake pedal: Slightly depressedApproximately 0V
[Ignition switch: ON]
• Brake pedal: Fully releasedBATTERY VOLTAGE
(11 - 14V)
CONDITION INDICATION
Brake pedal: Slightly depressed OFF
Brake pedal: Fully released ON
SEC011D
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
SEC013D

EC-524
< SERVICE INFORMATION >
DTC P1572 ICC BRAKE SWITCH
Without CONSULT-II
Check voltage between ECM terminal 101 and ground under the fol-
lowing conditions.
OK or NG
OK >> GO TO 14.
NG >> GO TO 10.
3.CHECK DTC WITH ICC UNIT
Refer to ACS-34
.
OK or NG
OK >> GO TO 4.
NG >> Repair or replace.
4.CHECK ICC BRAKE HOLD RELAY POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect ICC brake hold relay.
3. Turn ignition switch ON.
4. Check voltage between ICC brake hold relay terminal 4 and
ground with CONSULT-II or tester.
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5.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 hold relay and fuse
>> Repair open circuit or short to ground or short to power in harness or connectors.
CONDITION VOLTAGE
Brake pedal: Fully released Approximately 0V
Brake pedal: Slightly depressed Battery voltage
PBIB1537E
BBIA0471E
Voltage: Battery voltage
MBIB0059E