o2 sensor NISSAN ALMERA 2001 Service Manual

6 DETECT MALFUNCTIONING PART
Check the following.
+Joint connector-5 (If so equipped)
+Harness for open or short between ECM and joint connector
+Harness for open or short between joint connector and camshaft position sensor
©Repair open circuit or short to ground or short to power in harness or connectors.
7 CHECK GROUND CIRCUIT
1. Turn ignition switch ªOFFº.
2. Check harness continuity between sensor terminal 1 or 3 and engine ground.
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©Repair open circuit or short to ground or short to power in harness or connectors.
8 CHECK CAMSHAFT POSITION SENSOR
Refer to ªComponent Inspectionº, EC-342.
OK or NG
OK©GO TO 9.
NG©Replace camshaft position sensor.
9 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-177.
©INSPECTION END
DTC P0340 CAMSHAFT POSITION SENSOR (CMPS) (PHASE)QG
Diagnostic Procedure (Cont'd)
EC-341

SEF122X
Component Inspection=NJEC0226CAMSHAFT POSITION SENSORNJEC0226S011. Disconnect camshaft position sensor (PHASE) harness con-
nector.
2. Loosen the fixing bolt of the sensor.
3. Remove the sensor.
4. Visually check the sensor for chipping.
5. Check resistance as shown in the figure.
Terminal No. (Polarity) ResistanceW[at 25ÉC (77ÉF)]
3 (+) - 1 (±)
Except 0 or¥ 2 (+) - 1 (±)
3 (+) - 2 (±)
If NG, replace camshaft position sensor.
DTC P0340 CAMSHAFT POSITION SENSOR (CMPS) (PHASE)QG
Component Inspection
EC-342

DescriptionNJEC0227SYSTEM DESCRIPTIONNJEC0227S01
Sensor Input Signal to ECMECM func-
tionActuator
Crankshaft position sensor (POS) Engine speed
EGR vol-
ume controlEGR volume control valve Camshaft position sensor (PHASE) Engine speed and cylinder number
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Ignition switch Start signal
Throttle position sensor Throttle position
Vehicle speed sensor Vehicle speed
Battery Battery voltage
Air conditioner switch Air conditioner operation
Power steering oil pressure switch Power steering load signal
Electrical load Electrical load signal
PNP switch Park/Neutral position signal
This system controls flow rate of EGR led from exhaust manifold
to intake manifold. The opening of the EGR by-pass passage in the
EGR volume control valve changes to control the flow rate. A
built-in step motor moves the valve in steps corresponding to the
ECM output pulses. The opening of the valve varies for optimum
engine control. The optimum value stored in the ECM is determined
by considering various engine conditions. The EGR volume control
valve remains close under the following conditions.
+Low engine coolant temperature
+Engine starting
+High-speed engine operation
+Extremely light load engine operation
+Engine idling
+Excessively high engine coolant temperature
+Wide open throttle
+Mass air flow sensor malfunction
+Low battery voltage
SEF551W
DTC P0400 EGR FUNCTION (CLOSED) (WHERE FITTED)QG
Description
EC-343

SEF552W
COMPONENT DESCRIPTIONNJEC0227S02EGR Volume Control ValveNJEC0227S0201The EGR volume control valve uses a step motor to control the flow
rate of EGR from exhaust manifold. This motor has four winding
phases. It operates according to the output pulse signal of the
ECM. Two windings are turned ON and OFF in sequence. Each
time an ON pulse is issued, the valve opens or closes, changing
the flow rate. When no change in the flow rate is needed, the ECM
does not issue the pulse signal. A certain voltage signal is issued
so that the valve remains at that particular opening.
CONSULT-II Reference Value in Data Monitor
Mode
NJEC0502Specification data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
EGR TEMP SEN+Engine: After warming up Less than 4.5V
EGR VOL CON/V+Engine: After warming up
+Air conditioner switch: ªOFFº
+Shift lever: ªNº
+No-loadIdle 0 step
Revving engine up to 3,000 rpm
quickly10 - 55 step
ECM Terminals and Reference ValueNJEC0503Specification 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)
8
9
17
18SB
W/B
R/Y
BR/REGR volume control valve[Engine is running]
+Idle speed0 - 14V
58 B Sensor's ground[Engine is running]
+Warm-up condition
+Idle speed0V
72 P/B EGR temperature sensor[Engine is running]
+Warm-up condition
+Idle speedLess than 4.5V
[Engine is running]
+Warm-up condition
+EGR system is operating.0-1V
SEF073P
On Board Diagnosis LogicNJEC0228If the absence of EGR flow is detected by EGR temperature sen-
sor under the condition that calls for EGR, a low-flow malfunction
is diagnosed.
DTC P0400 EGR FUNCTION (CLOSED) (WHERE FITTED)QG
Description (Cont'd)
EC-344

DTC No. Malfunction is detected when ... Check Items (Possible Cause)
P0400
0400+No EGR flow is detected under conditions that call for
EGR.+Harness or connectors
(EGR volume control valve circuit is open or
shorted.)
+EGR volume control valve stuck closed
+Dead (Weak) battery
+EGR passage clogged
+EGR temperature sensor and circuit
+Exhaust gas leaks
SEF013Y
SEF845Y
SEF846Y
SEF235Y
DTC Confirmation ProcedureNJEC0229CAUTION:
Always drive vehicle at a safe speed.
NOTE:
+If ªDTC Confirmation Procedureº has been previously
conducted, always turn ignition switch ªOFFº and wait at least
9 seconds before conducting the next test.
+P0400 will not be displayed at ªSELF-DIAG RESULTSº mode
with CONSULT-II even though DTC work support test result is
ªNGº.
TESTING CONDITION:
+Before performing the following procedure, confirm bat-
tery voltage is more than 10V at idle, then stop engine
immediately.
+For best result, perform the test at a temperature of 0ÉC
(32ÉF) or higher.
With CONSULT-II
1) Turn ignition switch ªOFFº and wait at least 9 seconds.
2) Turn ignition switch ªONº.
3) Check ªCOOLAN TEMP/Sº in ªDATA MONITORº mode with
CONSULT-II and confirm it is within the range listed below.
COOLAN TEMP/S: Less than 40ÉC (104ÉF)
If the value is out of range, park the vehicle in a cool place and
allow the engine temperature to stabilize. Do not attempt to
lower the engine coolant temperature with a fan or means
other than ambient air. Doing so may produce an inaccurate
diagnostic result.
4) Start engine and let it idle monitoring ªCOOLAN TEMP/Sº
value. When the ªCOOLAN TEMP/Sº value reaches 70ÉC
(158ÉF), immediately go to the next step.
5) Select ªEGR SYSTEM P0400º of ªEGR SYSTEMº in ªDTC
WORK SUPPORTº mode with CONSULT-II.
6) Touch ªSTARTº.
7) Accelerate vehicle to a speed of 40 km/h (25 MPH) once and
then stop vehicle with engine running.
If ªCOMPLETEDº appears on CONSULT-II screen, go to step
9.
If ªCOMPLETEDº does not appear on CONSULT-II screen, go
to the following step.
8) When the following conditions are met, ªTESTINGº will be dis-
played on the CONSULT-II screen. Maintain the conditions
until ªTESTINGº changes to ªCOMPLETEDº. (It will take
approximately 45 seconds or more.)
DTC P0400 EGR FUNCTION (CLOSED) (WHERE FITTED)QG
On Board Diagnosis Logic (Cont'd)
EC-345

4 CHECK OUTPUT SIGNAL CIRCUIT
1. Turn ignition switch ªOFFº.
2. Disconnect ECM harness connector.
3. Check harness continuity between
ECM terminal 8 and terminal 1,
ECM terminal 9 and terminal 4,
ECM terminal 17 and terminal 3,
ECM terminal 18 and terminal 6.
Refer to wiring diagram.
Continuity should exist.
If OK, check harness for short to ground and short to power.
OK or NG
OK©GO TO 5.
NG©Repair open circuit, short to ground or short to power in harness connectors.
5 CHECK EGR PASSAGE
Check EGR passage for clogging and cracks.
OK or NG
OK©GO TO 6.
NG©Repair or replace EGR passage.
6 CHECK EGR TEMPERATURE SENSOR
Refer to ªCOMPONENT INSPECTIONº, EC-424.
OK or NG
OK©GO TO 7.
NG©Replace EGR temperature sensor.
7 CHECK EGR VOLUME CONTROL VALVE
Refer to ªCOMPONENT INSPECTIONº, EC-351.
OK or NG
OK©GO TO 8.
NG©Replace EGR volume control valve.
8 CHECK INTERMITTENT INCIDENT
Perform ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-177.
©INSPECTION END
DTC P0400 EGR FUNCTION (CLOSED) (WHERE FITTED)QG
Diagnostic Procedure (Cont'd)
EC-350

DescriptionNJEC0504SYSTEM DESCRIPTIONNJEC0504S01
Sensor Input Signal to ECMECM func-
tionActuator
Crankshaft position sensor (POS) Engine speed
EGR vol-
ume controlEGR volume control valve Camshaft position sensor (PHASE) Engine speed and cylinder number
Mass air flow sensor Amount of intake air
Engine coolant temperature sensor Engine coolant temperature
Ignition switch Start signal
Throttle position sensor Throttle position
Vehicle speed sensor Vehicle speed
Battery Battery voltage
Air conditioner switch Air conditioner operation
Power steering oil pressure switch Power steering load signal
Electrical load Electrical load signal
PNP switch Park/Neutral position signal
This system controls flow rate of EGR led from exhaust manifold
to intake manifold. The opening of the EGR by-pass passage in the
EGR volume control valve changes to control the flow rate. A
built-in step motor moves the valve in steps corresponding to the
ECM output pulses. The opening of the valve varies for optimum
engine control. The optimum value stored in the ECM is determined
by considering various engine conditions. The EGR volume control
valve remains close under the following conditions.
+Low engine coolant temperature
+Engine starting
+High-speed engine operation
+Extremely light load engine operation
+Engine idling
+Excessively high engine coolant temperature
+Wide open throttle
+Mass air flow sensor malfunction
+Low battery voltage
SEF551W
DTC P0403 EGR VOLUME CONTROL VALVE (CIRCUIT)
(WHERE FITTED)
QG
Description
EC-352

SEF184UD
On Board Diagnosis LogicNJEC0240The ECM monitors the switching frequency ratio of heated oxygen
sensors 1 (front) and 2 (rear).
A three way catalyst with high oxygen storage capacity will indicate
a low switching frequency of heated oxygen sensor 2 (rear). As
oxygen storage capacity decreases, the heated oxygen sensor 2
(rear) switching frequency will increase.
When the frequency ratio of heated oxygen sensors 1 (front) and
2 (rear) approaches a specified limit value, the three way catalyst
malfunction is diagnosed.
DTC No. Malfunction is detected when ... Check Items (Possible Cause)
P0420
0420+Three way catalyst does not operate properly.
+Three way catalyst does not have enough oxygen stor-
age capacity.+Three way catalyst
+Exhaust tube
+Intake air leaks
+Injectors
+Injector leaks
+Spark plug
+Improper ignition timing
SEF847Y
SEF848Y
SEF560X
DTC Confirmation ProcedureNJEC0241CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If ªDTC Confirmation Procedureº has been previously conducted,
always turn ignition switch ªOFFº and wait at least 9 seconds
before conducting the next test.
With CONSULT-II
TESTING CONDITION:
+Open engine hood before conducting following proce-
dure.
+Do not hold engine speed more than 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.
If ªCOMPLETEDº appears on the CONSULT-II screen, go to
step 7.
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-360.
DTC P0420 THREE WAY CATALYST FUNCTIONQG
On Board Diagnosis Logic
EC-359

SEF074X
Overall Function CheckNJEC0242Use this procedure to check the overall function of the three way
catalyst. During this check, a 1st trip DTC might not be confirmed.
Without CONSULT-II
1) 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 62 (HO2S1
signal), 63 (HO2S2 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 terminal 63 and engine ground is much less
than that of ECM terminal 62 and engine ground.
Switching frequency ratio = A/B
A: Heated oxygen sensor 2 (rear) voltage switching fre-
quency
B: Heated oxygen sensor 1 (front) voltage switching fre-
quency
This ratio should be less than 0.75.
If the ratio is greater than above, it means three way catalyst
does not operate properly.
NOTE:
If the voltage at terminal 62 does not switch periodically more
than 5 times within 10 seconds at step 4, perform trouble
diagnosis for DTC P0133 first. (See EC-236.)
Diagnostic ProcedureNJEC0243
1 CHECK EXHAUST SYSTEM
Visually check exhaust tubes and muffler for dent.
OK or NG
OK©GO TO 2.
NG©Repair or replace.
DTC P0420 THREE WAY CATALYST FUNCTIONQG
Overall Function Check
EC-360

2 CHECK EXHAUST AIR LEAK
1. Start engine and run it at idle.
2. Listen for an exhaust air leak before the 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.
4 CHECK IGNITION TIMING
Check for ignition timing.
Refer to ªBASIC INSPECTIONº, EC-100.
OK or NG
OK©GO TO 5.
NG©Check camshaft position sensor (PHASE) (EC-335) and crankshaft position sensor
(POS) (EC-328).
DTC P0420 THREE WAY CATALYST FUNCTIONQG
Diagnostic Procedure (Cont'd)
EC-361