2001 INFINITI QX4 IDX

ECM Terminals and Reference Value=NBEC0664Specification 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)
85 YCrankshaft position
sensor (POS)[Engine is running]
IIdle speedApproximately 2.4V
SEF057V
[Engine is running]
IEngine speed is 2,000 rpm.Approximately 2.3V
SEF058V
On Board Diagnosis LogicNBEC0193Malfunction is detected when 1É signal is not entered to ECM for
the first few seconds during engine cranking, or 1É signal is not
entered to ECM during engine running.
Possible CauseNBEC0493IHarness or connectors
(The crankshaft position sensor (POS) circuit is open or
shorted.)
ICrankshaft position sensor (POS)
IStarter motor (Refer to EL section.)
IStarting system circuit (Refer to EL section.)
IDead (Weak) battery
GI
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DTC P0335 CRANKSHAFT POSITION SENSOR (CKPS) (POS)
ECM Terminals and Reference Value
EC-335

Wiring DiagramNBEC0195
MEC959C
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DTC P0335 CRANKSHAFT POSITION SENSOR (CKPS) (POS)
Wiring Diagram
EC-337

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

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

SEF484Y
On Board Diagnosis LogicNBEC0214The ECM monitors the switching frequency ratio of heated oxygen
sensors 1 (front) and 2 (rear).
A warm-up three way catalyst with high oxygen storage capacity
will indicate a low switching frequency of rear heated oxygen sen-
sor. As oxygen storage capacity decreases, the rear heated oxy-
gen sensor switching frequency will increase.
When the frequency ratio of front and rear heated oxygen sensors
approaches a specified limit value, the warm-up three way catalyst
malfunction is diagnosed.
Malfunction is detected when warm-up three way catalyst does not
operate properly, warm-up three way catalyst does not have
enough oxygen storage capacity.
Possible CauseNBEC0504IWarm-up three way catalyst
IExhaust tube
IIntake air leaks
IInjectors
IInjector leaks
ISpark plug
IImproper ignition timing
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DTC P0420 (RIGHT BANK, -B1), P0430 (LEFT BANK, -B2) THREE WAY
CATALYST FUNCTION
On Board Diagnosis Logic
EC-347

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