ecm INFINITI QX56 2010 Factory Service Manual

P1574 ASCD VEHICLE SPEED SENSOREC-351
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P1574 ASCD VEHICLE SPEED SENSOR
Component DescriptionINFOID:0000000005149413
The ECM receives two vehicle speed sensor signals via
CAN communication line. One is sent from combina-
tion meter and the other is from TCM (Transmission control module). The ECM uses these signals for ASCD
control. Refer to EC-33, "
System Description" for ASCD functions.
On Board Diagnosis LogicINFOID:0000000005149414
• This self-diagnosis has the one trip detection logic.
• The MIL will not light up for this self-diagnosis.
NOTE:
• If DTC P1574 is displayed with DTC UXXXX, first perform the tr ouble diagnosis for DTC UXXXX.
• If DTC P1574 is displayed with DT C P0500, first perform the trouble diagnosis for DTC P0500. Refer
to EC-275, "
On Board Diagnosis Logic".
• If DTC P1574 is displayed with DT C P0605, first perform the trouble diagnosis for DTC P0605. Refer
to EC-286, "
On Board Diagnosis Logic".
• If DTC P1574 is displayed with DT C P0607, first perform the trouble diagnosis for DTC P0607. Refer
to EC-288, "
On Board Diagnosis Logic".
DTC Confirmation ProcedureINFOID:0000000005149415
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure
before conducting the next step.
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
TESTING CONDITION:
Step 3 may be conducted with the dr ive 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.
1. Start engine (VDC switch OFF).
2. Drive the vehicle at more than 40 km/h (25 MPH).
3. Check DTC.
4. If DTC is detected, go to EC-351, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000005149416
1.CHECK DTC WITH TCM
Check DTC with TCM. Refer to TM-30, "
OBD-II Diagnostic Trouble Code (DTC)".
OK or NG
OK >> GO TO 2.
NG >> Perform trouble shooting relevant to DTC indicated.
2.CHECK DTC WITH ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT)
Refer to BRC-23, "
CONSULT-III Function (ABS)".
DTC No. Trouble Diagnosis
Name DTC Detecting Condit
ion Possible Cause
P1574
1574 ASCD vehicle speed
sensor ECM detects a difference between two vehicle
speed signals is out of the specified range. • Harness or connectors
(The CAN communication line is open or
shorted.)
• Combination meter
• ABS actuator and electric unit (control unit)
• Wheel sensor
•TCM
•ECM
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P1805 BRAKE SWITCHEC-353
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P1805 BRAKE SWITCH
DescriptionINFOID:0000000005149417
Brake switch signal is applied to the ECM through t
he stop lamp switch when the brake pedal is depressed.
This signal is used mainly to decrease the engine speed when the vehicle is driving.
On Board Diagnosis LogicINFOID:0000000005149418
The MIL will not light up for this self-diagnosis.
FA I L - S A F E M O D E
When the malfunction is detected, the ECM enters fail-safe mode.
DTC Confirmation ProcedureINFOID:0000000005149419
1. Turn ignition switch ON.
2. Fully depress the brake pedal for at least 5 seconds.
3. Erase the DTC with CONSULT-III.
4. Check 1st trip DTC.
5. If 1st trip DTC is detected, go to EC-353, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000005149420
1.CHECK OVERALL FUNCTION-II
With CONSULT-III
Check “BRAKE SW2” indication in “DATA MONITOR” mode.
Without CONSULT-III
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1805
1805 Brake switch A brake switch signal is not sent to ECM for ex-
tremely long time while the vehicle is driving. • Harness or connectors
(Stop lamp switch circuit is open or short-
ed.)
• Stop lamp switch
Engine operating condition in fail-safe mode
ECM controls the electric throttle control actuator by regulating the throttle opening to a small range.
Therefore, acceleration will be poor. Vehicle condition Driving condition
When engine is idling Normal
When accelerating Poor acceleration
CONDITIONINDICATION
Brake pedal: Fully released OFF
Brake pedal: Slightly depressed ON
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EC-354
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P1805 BRAKE SWITCH
Check voltage between ECM terminal 101 and ground under the fol-
lowing conditions.
OK or NG
OK >> GO TO 6.
NG >> GO TO 2.
2.CHECK STOP LAMP SWIT
CH POWER SUPPLY CIRCUIT
1. Disconnect stop lamp switch harness connector.
2. Check voltage between stop lamp switch terminal 3 and ground with CONSULT-III or tester.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
3.DETECT MALFUNCTIONING PART
Check the following.
• Harness connectors M31, E152
• Fuse block (J/B) connector M60
• 10 A fuse (No. 20)
• Harness for open and short between stop lamp switch and battery
>> Repair open circuit or short to ground or short to power in harness or connectors.
4.CHECK STOP LAMP SWITCH INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminal 101 and stop lamp switch terminal 4. Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
CONDITION VOLTAGE
Brake pedal: Fully released Approximately 0 V
Brake pedal: Slightly depressed Battery voltage
PBIB1537E
BBIA0373E
Voltage: Battery voltage
PBIB2102E
Continuity should exist.
Revision: April 20092010 QX56

EC-356
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P2100, P2103 THROTTLE
CONTROL MOTOR RELAY
P2100, P2103 THROTTLE CONTROL MOTOR RELAY
Component DescriptionINFOID:0000000005149422
Power supply for the throttle control motor is provided to the ECM via throttle control motor relay. The throttle
control motor relay is ON/OFF controlled by the ECM. When the ignition switch is turned ON, the ECM sends
an ON signal to throttle control motor relay and battery voltage is provided to the ECM. When the ignition
switch is turned OFF, the ECM sends an OFF signal to throttle control motor relay and battery voltage is not
provided to the ECM.
On Board Diagn osis LogicINFOID:0000000005149423
These self-diagnoses have the one trip detection logic.
FA I L - S A F E M O D E
When the malfunction is detected, ECM enters fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureINFOID:0000000005149424
NOTE:
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure
before conducting the next step.
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
PROCEDURE FOR DTC P2100
1. Turn ignition switch ON and wait at least 2 seconds.
2. Start engine and let it idle for 5 seconds.
3. Check DTC.
4. If DTC is detected, go to EC-356, "
Diagnosis Procedure".
PROCEDURE FOR DTC P2103
TESTING CONDITION:
Before performing the following procedure, co nfirm that battery voltage is more than 8 V.
1. Turn ignition switch ON and wait at least 1 second.
2. Check DTC.
3. If DTC is detected, go to EC-356, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000005149425
1.CHECK THROTTLE CONTROL MOTOR RELAY POWER SUPPLY CIRCUIT-I
1. Turn ignition switch OFF.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P2100
2100 Throttle control motor
relay circuit open ECM detects a voltage of power source for
throttle control motor is excessively low. • Harness or connectors
(Throttle control motor relay circuit is
open)
• Throttle control motor relay
P2103
2103 Throttle control motor
relay circuit short ECM detect the throttle control motor relay is
stuck ON. • Harness or connectors
(Throttle control motor relay circuit is
shorted)
• Throttle control motor relay
Engine operating condition in fail-safe mode
ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) b y the return
spring.
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P2100, P2103 THROTTLE CONTROL MOTOR RELAYEC-357
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2. Check voltage between ECM terminal 104 and ground with
CONSULT-III or tester.
OK or NG
OK >> GO TO 4.
NG >> GO TO 2.
2.CHECK THROTTLE CONTROL MOTOR RELAY POWER SUPPLY CIRCUIT-II
1. Disconnect ECM harness connector.
2. Disconnect IPDM E/R harness connector E122.
3. Check continuity between ECM terminal 104 and IPDM E/R terminal 47. Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 3.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
3.CHECK FUSE
1. Disconnect 20A fuse.
2. Check 20A fuse (No. 52) for blown.
OK or NG
OK >> GO TO 7.
NG >> Replace 20A fuse.
4.CHECK THROTTLE CONTROL MOTOR RELAY INPUT SIGNAL CIRCUIT-I
Check voltage between ECM terminal 3 and ground under the fol-
lowing conditions with CONSULT-III or tester.
OK or NG
OK >> GO TO 7.
NG >> GO TO 5.
5.CHECK THROTTLE CONTROL MOTOR RELAY INPUT SIGNAL CIRCUIT-II
1. Turn ignition switch OFF.
2. Disconnect ECM harness connector.
3. Disconnect IPDM E/R harness connector E119.
4. Check continuity between ECM terminal 3 and IPDM E/R terminal 6. Refer to Wiring Diagram.
5. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 7.
NG >> GO TO 6. Voltage: Battery voltage
PBIB1171E
Continuity should exist.
Ignition switch
Voltage
OFF Approximately 0 V
ON Battery voltage
(11 - 14 V)
MBIB0028E
Continuity should exist.
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EC-358
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P2100, P2103 THROTTLE
CONTROL MOTOR RELAY
6.DETECT MALFUNCTIONING PART
Check the following.
• Harness connectors E2, F32
• Harness for open or short between ECM and IPDM E/R
>> Repair open circuit or short to ground or short to power in harness or connectors.
7.CHECK INTERMITTENT INCIDENT
Refer to GI-35, "
How to Check Terminal" and GI-38, "Intermittent Incident".
OK or NG
OK >> Replace IPDM E/R. Refer to PCS-35, "Removal and Installation of IPDM E/R".
NG >> Repair or replace harness or connectors.
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P2101 ELECTRIC THROTTLE CONTROL FUNCTIONEC-359
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P2101 ELECTRIC THROTTLE CONTROL FUNCTION
DescriptionINFOID:0000000005149426
NOTE:
If DTC P2101 is displayed with DTC P2100 or 2119,
first perform the trouble diagnosis for DTC P2100
or P2119. Refer to EC-356
or EC-365.
Electric throttle control actuator consists of throttle control mo tor, throttle position sensor, etc.
The throttle control motor is operated by the ECM and it opens and closes the throttle valve.
The current opening angle of the throttle valve is detected by the throttle position sensor and it provides feed-
back to the ECM to control the throttle control motor to make the throttle valve opening angle properly in
response to driving condition.
On Board Diagnosis LogicINFOID:0000000005149427
This self-diagnosis has the on e trip detection logic.
FA I L - S A F E M O D E
When the malfunction is detected, ECM ent ers fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureINFOID:0000000005149428
NOTE:
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure
before conducting the next step.
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 11 V when
engine is running.
1. Turn ignition switch ON and wait at least 2 seconds.
2. Start engine and let it idle for 5 seconds.
3. Check DTC.
4. If DTC is detected, go to EC-359, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000005149429
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P2101
2101 Electric throttle control
performance Electric throttle control function does not oper-
ate properly. • Harness or connectors
(Throttle control motor circuit is open or
shorted)
• Electric throttle control actuator
Engine operating condition in fail-safe mode
ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) b y the return
spring.
Revision: April 20092010 QX56

EC-360
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P2101 ELECTRIC THROTTLE CONTROL FUNCTION
Refer to EC-85, "Ground Inspection".
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2.CHECK THROTTLE CONTROL MOTOR RELAY INPUT SIGNAL CIRCUIT-I
1. Check voltage between ECM terminal 3 and ground under the following conditions with CONSULT-III or tester.
OK or NG
OK >> GO TO 9.
NG >> GO TO 3.
3.CHECK THROTTLE CONTROL MOTOR RELAY POWER SUPPLY CIRCUIT-I
1. Turn ignition switch OFF.
2. Check voltage between ECM terminal 104 and ground with CONSULT-III or tester.
OK or NG
OK >> GO TO 6.
NG >> GO TO 4.
4.CHECK THROTTLE CONTROL MOTOR RELAY POWER SUPPLY CIRCUIT-II
1. Disconnect ECM harness connector.
2. Disconnect IPDM E/R harness connector E122.
3. Check harness continuity between ECM terminal 104 and IPDM E/R terminal 47. Refer to Wiring Diagram.
4. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 5.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
5.CHECK FUSE
1. Disconnect 20A fuse.
2. Check 20A fuse (No. 52) for blown.
OK or NG
BBIA0354E
Ignition switch Voltage
OFF Approximately 0 V
ON Battery voltage
(11 - 14 V)
MBIB0028E
Voltage: Battery voltage
PBIB1171E
Continuity should exist.
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P2101 ELECTRIC THROTTLE CONTROL FUNCTIONEC-361
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OK >> GO TO 8.
NG >> Replace 20A fuse.
6.CHECK THROTTLE CONTROL MOTOR
RELAY INPUT SIGNAL CIRCUIT-II
1. Disconnect ECM harness connector.
2. Disconnect IPDM E/R harness connector E119.
3. Check harness continuity between ECM terminal 3 and IPDM E/R terminal 6. Refer to Wiring Diagram.
4. 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 ECM and IPDM E/R
>> Repair open circuit or short to ground or short to power in harness or connectors.
8.CHECK INTERMITTENT INCIDENT
Refer to GI-35, "
How to Check Terminal" and GI-38, "Intermittent Incident".
OK or NG
OK >> Replace IPDM E/R. Refer to PCS-35, "Removal and Installation of IPDM E/R".
NG >> Repair or replace harness or connectors.
9.CHECK THROTTLE CONTROL MOTOR OUTPUT SIGNAL CIRCUIT FOR OPEN OR SHORT
1. Turn ignition switch OFF.
2. Disconnect electric throttle c ontrol actuator harness connector.
3. Disconnect ECM harness connector.
4. Check harness continuity between the following terminals. Refer to Wiring Diagram.
5. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 10.
NG >> Repair or replace.
10.CHECK ELECTRIC THROTTLE CONTROL ACTUATOR VISUALLY
1. Remove the intake air duct. Continuity should exist.
Electric throttle control
actuator terminal ECM terminal
Continuity
5 5
Should not exist
4 Should exist
6 5
Should exist
4 Should not exist
PBIB1480E
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P2118 THROTTLE CONTROL MOTOREC-363
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P2118 THROTTLE CONTROL MOTOR
Component DescriptionINFOID:0000000005149431
The throttle control motor is operated by the
ECM and it opens and closes the throttle valve.
The current opening angle of the throttle valve is detected by the throttle position sensor and it provides feed-
back to the ECM to control the throttle control motor to make the throttle valve opening angle properly in
response to driving condition.
On Board Diagnosis LogicINFOID:0000000005149432
This self-diagnosis has the on e trip detection logic.
FA I L - S A F E M O D E
When the malfunction is detected, the ECM enters fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureINFOID:0000000005149433
1. If DTC Confirmation Procedure has been previously conducted, always perform the following procedure
before conducting the next step.
a. Turn ignition switch OFF and wait at least 10 seconds.
b. Turn ignition switch ON.
c. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON and wait at least 2 seconds.
3. Start engine and let it idle for 5 seconds.
4. Check DTC.
5. If DTC is detected, go to EC-363, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000005149434
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. Refer to EC-85, "
Ground Inspection".
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P2118
2118 Throttle control motor
circuit short ECM detects short in both circuits between
ECM and throttle control motor. • Harness or connectors
(Throttle control motor circuit is shorted.)
• Electric throttle control actuator
(Throttle control motor)
Engine operating condition in fail-safe mode
ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) b y the return
spring.
BBIA0354E
Revision: April 20092010 QX56