2001 INFINITI QX4 ignition

8 CHECK FUEL PRESSURE
1. Install all removed parts.
2. Release fuel pressure to zero. Refer to EC-39.
3. Install fuel pressure gauge and check fuel pressure. Refer to EC-39.
At idle:
Approx. 235 kPa (2.4 kg/cm
2, 34 psi)
OK or NG
OK©GO TO 10.
NG©GO TO 9.
9 DETECT MALFUNCTIONING PART
Check the following.
IFuel pump and circuit (Refer to EC-625.)
IFuel pressure regulator (Refer to EC-40.)
IFuel lines (Refer to MA-16, ªChecking Fuel Linesº.)
IFuel filter for clogging
©Repair or replace.
10 CHECK IGNITION TIMING
Check the following items. Refer to ªBasic Inspectionº, EC-101.
MTBL0655
OK or NG
OK (With CONSULT-II)©GO TO 11.
OK (Without CONSULT-
II)©GO TO 12.
NG©Follow the ªBasic Inspectionº.
DTC P0300 - P0306 NO.6-1CYLINDER MISFIRE, MULTIPLE CYLINDER
MISFIRE
Diagnostic Procedure (Cont'd)
EC-324

12 CHECK HEATED OXYGEN SENSOR 1 (FRONT)
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Set voltmeter probes between ECM terminal 63 (HO2S1 bank 1 right signal) or 62 (HO2S1 bank 2 left signal) and
engine ground.
3. Check the following with engine speed held at 2,000 rpm constant under no load.
SEF967XA
CAUTION:
Discard any heated oxygen sensor which has been dropped from a height of more than 0.5 m (19.7 in) onto a
hard surface such as a concrete floor; use a new one.
OK or NG
OK©GO TO 14.
NG©GO TO 13.
13 REPLACE HEATED OXYGEN SENSOR 1 (FRONT)
1. Turn ignition switch ªOFFº.
2. Check heated oxygen sensor 1 (front) harness protector color.
SEF505Y
©Replace malfunctioning heated oxygen sensor 1 (front).
DTC P0300 - P0306 NO.6-1CYLINDER MISFIRE, MULTIPLE CYLINDER
MISFIRE
Diagnostic Procedure (Cont'd)
EC-326

SEF332I
Component DescriptionNBEC0185The knock sensor is attached to the cylinder block. It senses
engine knocking using a piezoelectric element. A knocking vibration
from the cylinder block is sensed as vibrational pressure. This
pressure is converted into a voltage signal and sent to the ECM.
Freeze frame data will not be stored in the ECM for the knock
sensor. The MIL will not light for knock sensor malfunction.
The knock sensor has one trip detection logic.
ECM Terminals and Reference ValueNBEC0663Specification 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)
93 W Knock sensor[Engine is running]
IIdle speedApproximately 2.5V
On Board Diagnosis LogicNBEC0187Malfunction is detected when an excessively low or high voltage
from the knock sensor is sent to ECM.
Possible CauseNBEC0491IHarness or connectors
(The knock sensor circuit is open or shorted.)
IKnock sensor
SEF058Y
DTC Confirmation ProcedureNBEC0188NOTE:
If ªDTC Confirmation Procedureº has been previously conducted,
always turn ignition switch ªOFFº and wait at least 10 seconds
before conducting the next test.
TESTING CONDITION:
Before performing the following procedure, confirm that bat-
tery voltage is more than 10V at idle.
DTC P0325 KNOCK SENSOR (KS)
Component Description
EC-328

WITH CONSULT-IINBEC0188S011) Turn ignition switch ªONº and select ªDATA MONITORº mode
with CONSULT-II
2) Start engine and run it for at least 5 seconds at idle speed.
3) If DTC is detected, go to ªDiagnostic Procedureº, EC-331.
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DTC P0325 KNOCK SENSOR (KS)
DTC Confirmation Procedure (Cont'd)
EC-329

Diagnostic ProcedureNBEC0190
1 CHECK KNOCK SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT-I
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Check resistance between ECM terminal 93 and engine ground.
NOTE:
It is necessary to use an ohmmeter which can measure more than 10 MW.
SEF321X
4. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 5.
NG©GO TO 2.
2 CHECK KNOCK SENSOR INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT-II
1. Disconnect knock sensor harness connector.
2. Check harness continuity between ECM terminal 93 and knock sensor terminal 2. 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 4.
NG©GO TO 3.
3 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors F19, F116
IHarness for open or short between ECM and knock sensor
©Repair open circuit or short to ground or short to power in harness or connectors.
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DTC P0325 KNOCK SENSOR (KS)
Diagnostic Procedure
EC-331

SEF058Y
DTC Confirmation ProcedureNBEC0194NOTE:
If ªDTC Confirmation Procedureº has been previously conducted,
always turn ignition switch ªOFFº and wait at least 10 seconds
before conducting the next test.
TESTING CONDITION:
Before performing the following procedure, confirm that bat-
tery voltage is more than 10.5V.
WITH CONSULT-IINBEC0194S011) Turn ignition switch ªONº and select ªDATA MONITORº mode
with CONSULT-II.
2) Crank engine for at least two seconds.
3) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-338.
WITH GSTNBEC0194S02Follow the procedure ªWith CONSULT-IIº above.
DTC P0335 CRANKSHAFT POSITION SENSOR (CKPS) (POS)
DTC Confirmation Procedure
EC-336

Diagnostic ProcedureNBEC0196
1 RETIGHTEN GROUND SCREWS
1. Turn ignition switch ªOFFº.
2. Loosen and retighten engine ground screws.
SEF959Y
©GO TO 2.
2 CHECK CKPS (POS) POWER SUPPLY CIRCUIT
1. Disconnect harness connectors E132, E135.
SEF978Y
2. Check voltage between harness connector E135 terminal 6 and ground with CONSULT-II or tester.
SEF979Y
3. Also check harness for short to ground and short to power.
OK or NG
OK©GO TO 4.
NG©GO TO 3.
DTC P0335 CRANKSHAFT POSITION SENSOR (CKPS) (POS)
Diagnostic Procedure
EC-338

10 CHECK CRANKSHAFT POSITION SENSOR (POS)-II
1. Reconnect disconnected harness connectors.
2. Turn ignition switch ªONº.
3. Check voltage between ECM terminal 85 and ground by briefly touching the sensor core with a flat-bladed screwdriv-
ers.
SEF343Z
OK or NG
OK©GO TO 11.
NG©Replace crankshaft position sensor (POS).
11 CHECK CKPS (POS) SHIELD CIRCUIT FOR OPEN AND SHORT
1. Disconnect harness connectors E132, E135.
2. Check harness continuity between harness connector E135 terminal 2 and engine ground. Refer to Wiring Diagram.
Continuity should exist.
3. Also check harness for short to power.
OK or NG
OK©GO TO 13.
NG©GO TO 12.
12 DETECT MALFUNCTIONING PART
Check the following.
IHarness connectors E132, E135
IHarness connectors E116, M114
IHarness connectors M32, F23
IHarness for open between harness connector E135 and engine ground
©Repair open circuit or short to power in harness or connectors.
13 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-140.
©INSPECTION END
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DTC P0335 CRANKSHAFT POSITION SENSOR (CKPS) (POS)
Diagnostic Procedure (Cont'd)
EC-341