relay INFINITI QX4 2001 Factory Owner's Manual

Fail-safe Chart=NBEC0040The ECM enters fail-safe mode, if any of the following malfunctions is detected due to the open or short cir-
cuit. When the ECM enters the fail-safe mode, the MIL illuminates.
DTC No. Detected items Engine operating condition in fail-safe mode
P0100 Mass air flow sensor circuit Engine speed will not rise more than 2,400 rpm due to the fuel cut.
P0115 Engine coolant temperature
sensor circuitEngine coolant temperature will be determined by ECM based on the time after
turning ignition switch ªONº or ªSTARTº.
CONSULT-II displays the engine coolant temperature decided by ECM.
ConditionEngine coolant temperature decided
(CONSULT-II display)
Just as ignition switch is turned
ON or Start40ÉC (104ÉF)
More than approx. 4 minutes
after ignition ON or Start80ÉC (176ÉF)
Except as shown above40 - 80ÉC (104 - 176ÉF)
(Depends on the time)
P0120 Throttle position sensor cir-
cuitThrottle position will be determined based on the injected fuel amount and the
engine speed.
Therefore, acceleration will be poor.
Condition Driving condition
When engine is idling Normal
When accelerating Poor acceleration
P1335 Crankshaft position sensor
(REF) circuitCompression TDC signal (120É signal) is controlled by camshaft position sensor
(PHASE) signal and crankshaft position sensor (POS) signal. Ignition timing will be
delayed 0É to 2É.
Unable to
access ECMECMECM fail-safe activating condition
The computing function of the ECM was judged to be malfunctioning.
When the fail-safe system activates (i.e., if the ECM detects a malfunction condi-
tion in the CPU of ECM), the MIL on the instrument panel lights to warn the driver.
However it is not possible to access ECM and DTC cannot be confirmed.
Engine control with fail-safe
When ECM fail-safe is operating, fuel injection, ignition timing, fuel pump operation,
IACV-AAC valve operation and cooling fan operation are controlled under certain
limitations.
ECM fail-safe operation
Engine speedEngine speed will not rise more than 3,000
rpm
Fuel injection Simultaneous multiport fuel injection system
Ignition timing Ignition timing is fixed at the preset valve
Fuel pumpFuel pump relay is ªONº when engine is running
and ªOFFº when engine stalls
IACV-AAC valve Full open
Replace ECM, if ECM fail-safe condition is confirmed.
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TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
Fail-safe Chart
EC-117

TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
25 W/G Tachometer[Engine is running]
IWarm-up condition
IIdle speed7-8VH
SEF579X
[Engine is running]
IWarm-up condition
IEngine speed is 2,500 rpm.7-8VH
SEF580X
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)
27 LG Air conditioner relay[Engine is running]
IBoth A/C switch and blower switch are ªONº
(Compressor is operating).0 - 1.0V
[Engine is running]
IA/C switch is ªOFFº.BATTERY VOLTAGE
(11 - 14V)
28 R/L Fuel pump relay[Ignition switch ªONº]
IFor 1 second after turning ignition switch ªONº
[Engine is running]0 - 1.5V
[Ignition switch ªONº]
I1 second passed after turning ignition switch
ªONº.BATTERY VOLTAGE
(11 - 14V)
29 GSwirl control valve con-
trol solenoid valve[Engine is running]
IIdle speed
IEngine coolant temperature is between 15 to
50ÉC (59 to 122ÉF).0 - 1.0V
[Engine is running]
IIdle speed
IEngine coolant temperature is above 55ÉC
(131ÉF).BATTERY VOLTAGE
(11 - 14V)
38 OR MIL[Ignition switch ªONº]0 - 1.0V
[Engine is running]
IIdle speedBATTERY VOLTAGE
(11 - 14V)
39 G/WVacuum cut valve
bypass valve[Ignition switch ªONº]BATTERY VOLTAGE
(11 - 14V)
40 G/YEVAP canister vent
control valve[Ignition switch ªONº]BATTERY VOLTAGE
(11 - 14V)
TROUBLE DIAGNOSIS Ð GENERAL DESCRIPTION
ECM Terminals and Reference Value (Cont'd)
EC-130

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

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

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

4 CHECK MAFS POWER SUPPLY CIRCUIT
1. Disconnect mass air flow sensor (MAFS) harness connector.
SEF960Y
2. Turn ignition switch ªONº.
3. Check voltage between MAFS terminals 2, 4 and ground with CONSULT-II or tester.
SEF297X
OK or NG
OK©GO TO 6.
NG©GO TO 5.
5 DETECT MALFUNCTIONING PART
Check the following.
IHarness for open or short between ECM relay and mass air flow sensor
IHarness for open or short between mass air flow sensor and ECM
©Repair harness or connectors.
6 CHECK MAFS GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Check harness continuity between MAFS terminal 3 and ECM terminal 73.
Refer to Wiring Diagram.
Continuity should exist.
4. Also check harness for short to power.
OK or NG
OK©GO TO 7.
NG©Repair open circuit or short to power in harness or connectors.
DTC P0100 MASS AIR FLOW SENSOR (MAFS)
Diagnostic Procedure (Cont'd)
EC-156

3 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors E132, E135
IHarness for open or short between ECM and crankshaft position sensor (POS)
IHarness for open or short between ECM relay and crankshaft position sensor (POS)
©Repair open circuit or short to ground or short to power in harness or connectors.
4 CHECK CKPS (POS) GROUND CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between harness connector E135 terminal 1 and engine ground. Refer to Wiring Diagram.
Continuity should exist.
2. Also check harness for short to power.
OK or NG
OK©GO TO 6.
NG©GO TO 5.
5 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors E132, E135
IHarness connectors E116, M114
IHarness connectors M32, F23
IHarness for open between crankshaft position sensor (POS) and ground.
©Repair open circuit or short to ground or short to power in harness or connectors.
6 CHECK CKPS (POS) INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal 85 and harness connector E135 terminal 5.
Refer to Wiring Diagram.
Continuity should exist.
3. 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.
IHarness connectors E132, E135
IHarness connectors E116, M114
IHarness connectors M32, F23
IHarness for open or short between ECM and crankshaft position sensor (POS)
©Repair open circuit or short to ground or short to power in harness or connectors.
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DTC P0335 CRANKSHAFT POSITION SENSOR (CKPS) (POS)
Diagnostic Procedure (Cont'd)
EC-339

Diagnostic ProcedureNBEC0255
1 CHECK IACV-AAC VALVE POWER SUPPLY CIRCUIT
1. Stop engine.
2. Disconnect IACV-AAC valve harness connector.
SEF994Y
3. Turn ignition switch ªONº.
4. Check voltage between IACV-AAC valve terminals 2, 5 and ground with CONSULT-II or tester.
SEF343X
OK or NG
OK©GO TO 3.
NG©GO TO 2.
2 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors E1, M1
IHarness connectors M33, F22
IHarness for open or short between IACV-AAC valve and ECM relay
©Repair harness or connectors.
DTC P0505 IDLE AIR CONTROL VALVE (IACV) Ð AUXILIARY AIR CONTROL
(AAC) VALVE
Diagnostic Procedure
EC-426

3 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors M32, F23
IHarness connectors E1, M1
IHarness for open or short between ECM and intake valve timing control position sensor
IHarness for open or short between ECM relay and intake valve timing control position sensor
©Repair open circuit or short to ground or short to power in harness or connectors.
4 CHECK INTAKE VALVE TIMING CONTROL POSITION SENSOR GROUND CIRCUIT FOR OPEN AND
SHORT
1. Turn ignition switch ªOFFº.
2. Check harness connector continuity between intake valve timing control position sensor harness connector terminal 1
and engine ground. Refer to Wiring Diagram.
Continuity should exist.
3. Also check harness for short to power.
OK or NG
OK©GO TO 5.
NG©Repair open circuit or short to power in harness or connectors.
5 CHECK INTAKE VALVE TIMING CONTROL POSITION SENSOR INPUT SIGNAL CIRCUIT
1. Disconnect ECM harness connector.
2. Check harness connectors continuity between ECM terminal 79 (Right) or 89 (Left) and terminal 2. Refer to Wiring Dia-
gram.
Continuity should exist.
3. 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 INTAKE VALVE TIMING CONTROL POSITION SENSOR INSTALLATION
Check that intake valve timing control position sensor is installed correctly as shown below.
SEF361Z
OK or NG
OK©GO TO 7.
NG©Install intake valve timing control position sensor correclty.
DTC P1140 (RIGHT, -B1), P1145 (LEFT, -B2) INTAKE VALVE TIMING CONTROL
POSITION SENSOR (CIRCUIT)
Diagnostic Procedure (Cont'd)
EC-488