ignition INFINITI QX4 2001 Factory Service Manual

TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
91 R Throttle position sensor[Engine is running]
IWarm-up condition
IAccelerator pedal fully released0.15 - 0.85V
[Ignition switch ªONº]
IAccelerator pedal fully depressed3.5 - 4.7V
92 G/BFuel tank temperature
sensor[Engine is running]Approximately 0 - 4.8V
Output voltage varies with
fuel tank temperature.
93 W Knock sensor[Engine is running]
IIdle speedApproximately 2.5V
101
102
103
104
105
107R/B
L/W
R/W
PU/R
R/Y
R/LInjector No. 1
Injector No. 5
Injector No. 2
Injector No. 6
Injector No. 3
Injector No. 4[Engine is running]
IIdle speedBATTERY VOLTAGE
(11 - 14V)
106
108B
BECM ground[Engine is running]
IIdle speedEngine ground
11 0
11 2B/W
B/WPower supply for ECM[Ignition switch ªONº]BATTERY VOLTAGE
(11 - 14V)
111 P/B Sensors' power supply[Ignition switch ªONº]Approximately 5V
114 G/RCommunication line
(LAN)[Engine is running]
IIdle speedApproximately 2V
115 LG/R Data link connector[Ignition switch ªONº]
ICONSULT-II or GST is disconnected.Approximately 2V
H: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)
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TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
ECM Terminals and Reference Value (Cont'd)
EC-135

ECM Terminals and Reference ValueNBEC0648Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
26 L/BECM relay
(Self shutt-off)[Engine is running]
[Ignition switch ªOFFº]
IFor a few seconds after turning ignition switch
ªOFFº0 - 1.5V
[Ignition switch ªOFFº]
IA few seconds passed after turning ignition
switch ªOFFºBATTERY VOLTAGE
(11 - 14V)
43 R Ignition switch[Ignition switch ªOFFº]0V
[Ignition switch ªONº]BATTERY VOLTAGE
(11 - 14V)
48 B ECM ground[Engine is running]
IIdle speedEngine ground
[Probe this terminal with (±)
tester probe when measuring]
57 B ECM ground[Engine is running]
IIdle speedEngine ground
12
67W/RPower supply for ECM
(Buck-up)[Ignition switch ªOFFº]BATTERY VOLTAGE
(11 - 14V)
108 B ECM ground[Engine is running]
IIdle speedEngine ground
11 0
11 2B/W
B/WPower supply for ECM[Ignition switch ªONº]BATTERY VOLTAGE
(11 - 14V)
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TROUBLE DIAGNOSIS FOR POWER SUPPLY
ECM Terminals and Reference Value
EC-141

DIAGNOSTIC PROCEDURENBEC0049
1 INSPECTION START
Start engine.
Is engine running?
YesorNo
Ye s©GO TO 9.
No©GO TO 2.
2 CHECK ECM POWER SUPPLY CIRCUIT-I
1. Turn ignition switch ªOFFº and then ªONº.
2. Check voltage between ECM terminal 43 and ground with CONSULT-II or tester.
SEF291X
OK or NG
OK©GO TO 4.
NG©GO TO 3.
3 DETECT MALFUNCTIONING PART
Check the following.
I10A fuses
IHarness connectors M33, F22
IHarness for open or short between ECM and ignition switch
©Repair harness or connectors.
4 CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-I
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminals 48, 57, 106, 108 and engine ground.
Refer to WIRING DIAGRAM.
Continuity should exist.
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.
TROUBLE DIAGNOSIS FOR POWER SUPPLY
Main Power Supply and Ground Circuit (Cont'd)
EC-144

5 CHECK POWER SUPPLY-II
1. Disconnect ECM relay.
SEF681UB
2. Check voltage between ECM relay terminals 1, 5 and ground with CONSULT-II or tester.
SEF956Y
OK or NG
OK©GO TO 7.
NG©GO TO 6.
6 DETECT MALFUNCTIONING PART
Check the following.
I7.5A and 10A fuses
IHarness for open or short between ECM relay and battery
©Repair open circuit or short to ground or short to power in harness or connectors.
7 CHECK OUTPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between ECM terminal 26 and ECM relay terminal 2.
Continuity should exist.
2. Also check harness for short to ground and short to power.
OK or NG
OK©Go to ªDTC P1320 IGNITION SIGNALº, EC-499.
NG©GO TO 8.
8 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors E1, M1 and M32, F23
IHarness for open or short between ECM relay and ECM
©Repair open circuit or short to ground or short to power in harness or connectors.
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TROUBLE DIAGNOSIS FOR POWER SUPPLY
Main Power Supply and Ground Circuit (Cont'd)
EC-145

9 CHECK ECM POWER SUPPLY CIRCUIT-II
1. Stop engine.
2. Check voltage between ECM terminal 67 and ground with CONSULT-II or tester.
SEF293X
OK or NG
OK©GO TO 11.
NG©GO TO 10.
10 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors E1, M1 and M32, F23
IHarness for open or short between ECM and fuse
©Repair harness or connectors.
11 CHECK ECM POWER SUPPLY CIRCUIT-III
1. Turn ignition switch ªONº and then ªOFFº.
2. Check voltage between ECM terminals 110, 112 and ground with CONSULT-II or tester.
SEF294X
OK or NG
OK©GO TO 17.
NG (Battery voltage
does not exist.)©GO TO 12.
NG (Battery voltage
exists for more than a
few seconds.)©GO TO 14.
TROUBLE DIAGNOSIS FOR POWER SUPPLY
Main Power Supply and Ground Circuit (Cont'd)
EC-146

12 CHECK ECM POWER SUPPLY CIRCUIT-IV
1. Disconnect ECM relay.
SEF681UB
2. Check voltage between ECM relay terminal 7 and ground with CONSULT-II or tester.
SEF957Y
OK or NG
OK©GO TO 14.
NG©GO TO 13.
13 DETECT MALFUNCTIONING PART
Check the following.
IHarness for open or short between ECM relay and 7.5A fuse
©Repair open circuit or short to ground or short to power in harness or connectors.
14 CHECK ECM POWER SUPPLY-V
1. Turn ignition switch ªOFFº and then ªONº.
2. Check voltage between ECM terminal 12 and ground with CONSULT-II or tester.
SEF331Z
OK or NG
OK©GO TO 16.
NG©GO TO 15.
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TROUBLE DIAGNOSIS FOR POWER SUPPLY
Main Power Supply and Ground Circuit (Cont'd)
EC-147

15 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors E1, M1
IHarness connectors M94, F27
I10A fuse
©Repair harness or connectors.
16 CHECK HARNESS CONTINUITY BETWEEN ECM RELAY AND ECM FOR OPEN AND SHORT
1. Check harness continuity between ECM terminals 110, 112 and ECM relay terminal 6.
Refer to WIRING DIAGRAM.
Continuity should exist.
2. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 18.
NG©GO TO 17.
17 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors E1, M1 and M32, F23
IHarness for open or short between ECM and ECM relay
©Repair open circuit or short to ground or short to power in harness or connectors.
18 CHECK ECM RELAY
1. Apply 12V direct current between ECM relay terminals 1 and 2.
2. Check continuity between relay terminals 3 and 5, 6 and 7.
SEF296X
OK or NG
OK©GO TO 19.
NG©Replace ECM relay.
19 CHECK ECM GROUND CIRCUIT FOR OPEN AND SHORT-II
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Check harness continuity between ECM terminals 48, 57, 106, 108 and engine ground.
Refer to WIRING DIAGRAM.
Continuity should exist.
4. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 20.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
TROUBLE DIAGNOSIS FOR POWER SUPPLY
Main Power Supply and Ground Circuit (Cont'd)
EC-148

SEF958Y
Component DescriptionNBEC0050The mass air flow sensor is placed in the stream of intake air. It
measures the intake flow rate by measuring a part of the entire
intake flow. It consists of a hot film that is supplied with electric
current from the ECM. The temperature of the hot film is controlled
by the ECM a certain amount. The heat generated by the hot film
is reduced as the intake air flows around it. The more air, the
greater the heat loss.
Therefore, the ECM must supply more electric current to maintain
the temperature of the hot film as air flow increases. The ECM
detects the air flow by means of this current change.
CONSULT-II Reference Value in Data Monitor
Mode
NBEC0051Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
MAS A/F SE-B1IEngine: After warming up
IAir conditioner switch: ªOFFº
IShift lever: ªNº
INo-loadIdle 1.2 - 1.8V
2,500 rpm 1.6 - 2.2V
CAL/LD VALUE dittoIdle 14.0 - 33.0%
2,500 rpm 12.0 - 25.0%
MASS AIRFLOW dittoIdle 2.0 - 6.0 g´m/s
2,500 rpm 7.0 - 20.0 g´m/s
ECM Terminals and Reference ValueNBEC0649Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
61 OR Mass air flow sensor[Engine is running]
IWarm-up condition
IIdle speed1.2 - 1.8V
[Engine is running]
IWarm-up condition
IEngine speed is 2,500 rpm.1.6 - 2.2V
73 B/PMass air flow sensor
ground[Engine is running]
IWarm-up condition
IIdle speedApproximately 0V
111 P/B Sensors' power supply[Ignition switch ªONº]Approximately 5V
DTC P0100 MASS AIR FLOW SENSOR (MAFS)
Component Description
EC-150

On Board Diagnosis LogicNBEC0053Malfunction is detected when
(Malfunction A)an excessively high voltage from the sensor is
sent to ECM when engine is not running,
(Malfunction B)an excessively low voltage from the sensor is sent
to ECM when engine is running,
(Malfunction C)a high voltage from the sensor is sent to ECM
under light load driving condition,
(Malfunction D)a low voltage from the sensor is sent to ECM
under heavy load driving condition,
(Malfunction E)a voltage from the sensor is constantly approx.
1.0V when engine is running.
FAIL-SAFE MODENBEC0053S02When the malfunction B is detected, the ECM enters fail-safe mode
and the MIL lights up.
Detected items Engine operating condition in fail-safe mode
Mass air flow sensor circuit Engine speed will not rise more than 2,400 rpm due to the fuel cut.
Possible CauseNBEC0426MALFUNCTION A OR CNBEC0426S01IHarness or connectors
(The sensor circuit is open or shorted.)
IMass air flow sensor
MALFUNCTION B, D OR ENBEC0426S02IHarness or connectors
(The sensor circuit is open or shorted.)
IIntake air leaks
IMass air flow sensor
DTC Confirmation ProcedureNBEC0054Perform ªPROCEDURE FOR MALFUNCTION Aº first.
If the 1st trip DTC cannot be confirmed, perform ªPROCE-
DURE FOR MALFUNCTION B AND Eº.
If there is no problem on ªPROCEDURE FOR MALFUNCTION
B AND Eº, perform ªPROCEDURE FOR MALFUNCTION Cº.
If there is no problem on ªPROCEDURE FOR MALFUNCTION
Cº, perform ªPROCEDURE FOR MALFUNCTION Dº.
NOTE:
If ªDTC Confirmation Procedureº has been previously conducted,
always turn ignition switch ªOFFº and wait at least 10 seconds
before conducting the next test.
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DTC P0100 MASS AIR FLOW SENSOR (MAFS)
On Board Diagnosis Logic
EC-151

SEF058Y
PROCEDURE FOR MALFUNCTION ANBEC0054S01With CONSULT-IINBEC0054S01011) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Wait at least 6 seconds.
4) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-155.
With GSTNBEC0054S0102Follow the procedure ªWith CONSULT-IIº above.
SEF058Y
PROCEDURE FOR MALFUNCTION B AND ENBEC0054S02With CONSULT-IINBEC0054S02011) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Start engine and wait 5 seconds at most.
4) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-155.
With GSTNBEC0054S0202Follow the procedure ªWith CONSULT-IIº above.
NOTE:
If 1st trip DTC is confirmed after more than 5 seconds, there may
be malfunction C.
SEF174Y
PROCEDURE FOR MALFUNCTION CNBEC0054S03NOTE:
If engine will not start or stops soon, wait at least 10 seconds with
engine stopped (Ignition switch ªONº) instead of running engine at
idle speed.
With CONSULT-IINBEC0054S03011) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Start engine and warm it up to normal operating temperature.
4) Run engine for at least 10 seconds at idle speed.
5) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-155.
With GSTNBEC0054S0302Follow the procedure ªWith CONSULT-IIº above.
DTC P0100 MASS AIR FLOW SENSOR (MAFS)
DTC Confirmation Procedure (Cont'd)
EC-152