2001 INFINITI QX4 engine

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

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

SEF252P
Component DescriptionNBEC0197The camshaft position sensor (PHASE) is located on the engine
front cover facing the camshaft sprocket. It detects the cylinder No.
signal.
The sensor consists of a permanent magnet, core and coil.
When engine is running, the gap between the sensor and the
camshaft sprocket will periodically change. Permeability near the
sensor also changes.
Due to the permeability change, the magnetic flux near the core is
changed. Therefore, the voltage signal generated in the coil is
changed.
The ECM receives the voltage signal and detects the cylinder No.
signal.
ECM Terminals and Reference ValueNBEC0665Specification 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)
66
76L
LCamshaft position sen-
sor (PHASE)[Engine is running]
IWarm-up condition
IIdle speedApproximately 4.2VH
(AC voltage)
SEF582X
H: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)
On Board Diagnosis LogicNBEC0199Malfunction is detected when
(Malfunction A)the cylinder No. signal is not sent to ECM for the
first few seconds during engine cranking,
(Malfunction B)the cylinder No. signal is not sent to ECM during
engine running,
(Malfunction C)the cylinder No. signal is not in the normal pattern
during engine running.
DTC P0340 CAMSHAFT POSITION SENSOR (CMPS) (PHASE)
Component Description
EC-342

Possible CauseNBEC0494IHarness or connectors
[The camshaft position sensor (PHASE) circuit is open or
shorted.]
ICamshaft position sensor (PHASE)
IStarter motor (Refer to SC section.)
IStarting system circuit (Refer to SC section.)
IDead (Weak) battery
DTC Confirmation ProcedureNBEC0200NOTE:
IPerform ªPROCEDURE FOR MALFUNCTION Aº first. If 1st
trip DTC cannot be confirmed, perform ªPROCEDURE
FOR MALFUNCTION B AND Cº.
IIf 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 at idle.
SEF013Y
PROCEDURE FOR MALFUNCTION ANBEC0200S01With CONSULT-IINBEC0200S01011) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Crank engine for at least 2 seconds.
4) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-345.
With GSTNBEC0200S0102Follow the procedure ªWith CONSULT-IIº above.
SEF058Y
PROCEDURE FOR MALFUNCTION B AND CNBEC0200S02With CONSULT-IINBEC0200S02011) Turn ignition switch ªONº.
2) Select ªDATA MONITORº mode with CONSULT-II.
3) Start engine and run it for at least 2 seconds at idle speed.
4) If 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-345.
With GSTNBEC0200S0202Follow the procedure ªWith CONSULT-IIº above.
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DTC P0340 CAMSHAFT POSITION SENSOR (CMPS) (PHASE)
Possible Cause
EC-343

Diagnostic ProcedureNBEC0202
1 CHECK STARTING SYSTEM
Turn ignition switch to ªSTARTº position.
Does the engine turn over?
Does the starter motor operate?
YesorNo
Ye s©GO TO 2.
No©Check starting system. (Refer to SC-10, ªSTARTING SYSTEMº.)
2 RETIGHTEN GROUND SCREWS
1. Turn ignition switch ªOFFº.
2. Loosen and retighten engine ground screws.
SEF959Y
©GO TO 3.
3 CHECK CMPS (PHASE) INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector and CMPS (PHASE) harness connector.
SEF982Y
3. Check harness continuity between CMPS (PHASE) terminal 2 and ECM terminals 66, 76. 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 4.
NG©Repair open circuit or short to ground or short to power in harness or connectors.
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DTC P0340 CAMSHAFT POSITION SENSOR (CMPS) (PHASE)
Diagnostic Procedure
EC-345

4 CHECK CMPS (PHASE) GROUND CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between CMPS (PHASE) terminal 1 and engine ground.
Continuity should exist.
2. 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 connector.
5 CHECK CAMSHAFT POSITION SENSOR (PHASE)-I
1. Loosen the fixing bolt of the camshaft position sensor (PHASE).
2. Remove the CMPS (PHASE).
3. Visually check the CMPS (PHASE) for chipping.
SEF583P
OK or NG
OK©GO TO 6.
NG©Replace camshaft position sensor (PHASE).
6 CHECK CAMSHAFT POSITION SENSOR (PHASE)-II
Check resistance between CMPS (PHASE) terminals 1 and 2 as shown below.
SEF325X
OK or NG
OK©GO TO 7.
NG©Replace camshaft position sensor (PHASE).
7 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-140.
©INSPECTION END
DTC P0340 CAMSHAFT POSITION SENSOR (CMPS) (PHASE)
Diagnostic Procedure (Cont'd)
EC-346

SEF344Z
DTC Confirmation ProcedureNBEC0215
SEF345Z
SEF560X
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.
WITH CONSULT-IINBEC0215S01TESTING CONDITION:
IOpen engine hood before conducting the following proce-
dure.
IDo not hold engine speed for more than the specified
minutes below.
1) Turn ignition switch ªONº.
2) Select ªDTC & SRT CONFIRMATIONº then ªSRT WORK SUP-
PORTº mode with CONSULT-II.
3) Start engine.
4) Rev engine up to 3,000±500 rpm and hold it for 3 consecutive
minutes then release the accelerator pedal completely.
5) Wait 5 seconds at idle.
6) Rev engine up to 2,500±500 rpm and maintain it until ªINCMPº
of CATALYST changes to ªCMPLTº (It will take approximately
5 minutes).
If not ªCMPLTº, stop engine and cool it down to less than 70ÉC
(158ÉF) and then retest from step 1.
7) Select ªSELF-DIAG RESULTSº mode with CONSULT-II.
8) Confirm that the 1st trip DTC is not detected.
If the 1st trip DTC is detected, go to ªDiagnostic Procedureº,
EC-349.
SEF329X
SEF330X
Overall Function CheckNBEC0216Use this procedure to check the overall function of the warm-up
three way catalyst. During this check, a 1st trip DTC might not be
confirmed.
CAUTION:
Always drive vehicle at a safe speed.
WITH GSTNBEC0216S011) Start engine and drive vehicle at a speed of more than 70 km/h
(43 MPH) for 2 consecutive minutes.
2) Stop vehicle with engine running.
3) Set voltmeters probes between ECM terminals 63 [heated oxy-
gen sensor 1 (front) right bank signal], 62 [heated oxygen
sensor 1 (front) left bank signal] and engine ground, and ECM
terminals 72 [heated oxygen sensor 2 (rear) right bank signal],
71 [heated oxygen sensor 2 (rear) left bank signal] and engine
ground.
4) Keep engine speed at 2,000 rpm constant under no load.
5) Make sure that the voltage switching frequency (high & low)
between ECM terminals 72 and engine ground, or 71 and
engine ground is very less than that of ECM terminals 63 and
engine ground, or 62 and engine ground.
Switching frequency ratio = A/B
DTC P0420 (RIGHT BANK, -B1), P0430 (LEFT BANK, -B2) THREE WAY
CATALYST FUNCTION
DTC Confirmation Procedure
EC-348

A: Rear heated oxygen sensor voltage switching fre-
quency
B: Front heated oxygen sensor voltage switching fre-
quency
This ratio should be less than 0.75.
If the ratio is greater than above, it means warm-up three way
catalyst does not operate properly. Go to ªDiagnostic
Procedureº, EC-349.
NOTE:
If the voltage at terminal 62 or 63 does not switch periodically more
than 5 times within 10 seconds at step 5, perform trouble diagno-
sis for ªDTC P0133, P0153º first. (See EC-218.)
Diagnostic ProcedureNBEC0217
1 CHECK EXHAUST SYSTEM
Visually check exhaust tubes and muffler for dent.
OK or NG
OK©GO TO 2.
NG©Repair or replace.
2 CHECK EXHAUST AIR LEAK
1. Start engine and run it at idle.
2. Listen for an exhaust air leak before the warm-up three way catalyst.
SEF099P
OK or NG
OK©GO TO 3.
NG©Repair or replace.
3 CHECK INTAKE AIR LEAK
Listen for an intake air leak after the mass air flow sensor.
OK or NG
OK©GO TO 4.
NG©Repair or replace.
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DTC P0420 (RIGHT BANK, -B1), P0430 (LEFT BANK, -B2) THREE WAY
CATALYST FUNCTION
Overall Function Check (Cont'd)
EC-349