1998 NISSAN PATROL Engine Control Workshop Manual

TEC423
TROUBLE DIAGNOSIS FOR ``CAM POS SEN (PUMP)'' (DTC 11)
Camshaft Position Sensor (CMPS) (PUMP)
(Cont'd)
EC-71

DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK INPUT SIGNAL CIRCUIT.
1. Turn ignition switch ``OFF''.
2. Disconnect electronic fuel injection
pump harness connector and ECM har-
ness connector.
3. Check harness continuity between ter-
minal
V1and ECM terminalsV41,V45.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
OK
cNG
Repair open circuit or short
to ground or short to power
in harness or connectors.
CHECK GROUND CIRCUIT-I.
1. Turn ignition switch ``OFF''.
2. Check harness continuity between ter-
minal
V2and ECM terminalsV28,V33.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
OK
cNG
Repair open circuit or short
to ground or short to power
in harness or connectors.
CHECK GROUND CIRCUIT-II.
1. Loosen and retighten engine ground
screws.
2. Check harness continuity between ter-
minal
V3and engine ground.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
OK
cNG
Check the following.
+Joint connector
F19
+Harness for open or
short between electronic
fuel injection pump and
engine ground
If NG, repair harness or
connectors.
CHECK COMPONENT
[Camshaft position sensor (PUMP)].
Refer to ``COMPONENT INSPECTION''
on next page.
OK
cNG
Replace camshaft position
sensor (PUMP).
Disconnect and reconnect harness connec-
tors in the circuit. Then retest.
Trouble is not ®xed.
Check ECM pin terminals for damage or
the connection of ECM harness connector.
Reconnect ECM harness connector and
retest.
INSPECTION END
SEF675V
SEF731V
SEF732V
SEF676V
SEF733V
.
.
.
.
.
.
.
TROUBLE DIAGNOSIS FOR ``CAM POS SEN (PUMP)'' (DTC 11)
Camshaft Position Sensor (CMPS) (PUMP)
(Cont'd)
EC-72

COMPONENT INSPECTION
Camshaft position sensor (PUMP)
1. Disconnect electronic fuel injection pump harness connector.
2. Loosen the camshaft position sensor (PUMP).
3. Remove the sensor.
4. Visually check the sensor for chipping.
5. Check resistance between terminals
V1andV2.
Resistance:
Approximately 1,360 - 1,840W[at 25ÉC (77ÉF)]
If NG, replace camshaft position sensor (PUMP).
SEF573S
SEF677V
TROUBLE DIAGNOSIS FOR ``CAM POS SEN (PUMP)'' (DTC 11)
Camshaft Position Sensor (CMPS) (PUMP)
(Cont'd)
EC-73

Mass Air Flow Sensor (MAFS)
COMPONENT DESCRIPTION
The mass air ¯ow sensor is placed in the stream of intake air. It
measures the intake air ¯ow rate by measuring a part of the entire
intake air ¯ow. It consists of a hot wire that is supplied with electric
current from the ECM. The temperature of the hot wire is controlled
by the ECM a certain amount. The heat generated by the hot wire
is reduced as the intake air ¯ows around it. The more air, the
greater the heat loss.
Therefore, the ECM must supply more electric current to the hot
wire as air ¯ow increases. This maintains the temperature of the hot
wire. The ECM detects the air ¯ow by means of this current change.
CONSULT REFERENCE VALUE IN DATA MONITOR MODE
Remarks: Speci®cation data are reference values.
MONITOR ITEM CONDITION SPECIFICATION
MAS AIR/FL SE+Engine: After warming up
+Air conditioner switch: ``OFF''
+Shift lever: ``N''
+No-loadIdle 1.6 - 2.0V
ECM TERMINALS AND REFERENCE VALUE
Remarks: Speci®cation data are reference values, and are measured between each terminal andV43(ECCS
ground) with a voltmeter.
TER-
MINAL
NO.WIRE
COLORITEM CONDITIONDATA
(DC voltage)
35 R Mass air ¯ow sensorEngine is running.
(Warm-up condition)
Idle speed1.6 - 2.0V
50 B Sensors' groundEngine is running.
(Warm-up condition)
Idle speedApproximately 0V
ON BOARD DIAGNOSIS LOGIC
Diagnostic
Trouble
Code No.Malfunction is detected when ...Check Items
(Possible Cause)
12+An excessively high or low voltage from the sensor is
sent to ECM.+Harness or connectors
(The sensor circuit is open or shorted.)
+Mass air ¯ow sensor
SEF734V
TROUBLE DIAGNOSIS FOR ``MASS AIR FLOW SEN'' (DTC 12)
EC-74

DIAGNOSTIC TROUBLE CODE CONFIRMATION
PROCEDURE
1) Turn ignition switch ``ON'', and wait at least 6 seconds.
2) Select ``DATA MONITOR'' mode with CONSULT.
3) Start engine and wait at least 3 seconds.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------OR-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
1) Turn ignition switch ``ON'', and wait at least 6 seconds.
2) Start engine and wait at least 3 seconds.
3) Turn ignition switch ``OFF'', wait at least 5 seconds and
then turn ``ON''.
4) Perform ``Diagnostic Test Mode II (Self-diagnostic
results)'' with ECM.
SEF735V
TROUBLE DIAGNOSIS FOR ``MASS AIR FLOW SEN'' (DTC 12)
Mass Air Flow Sensor (MAFS) (Cont'd)
EC-75

TEC424
TROUBLE DIAGNOSIS FOR ``MASS AIR FLOW SEN'' (DTC 12)
Mass Air Flow Sensor (MAFS) (Cont'd)
EC-76

DIAGNOSTIC PROCEDURE
INSPECTION START
CHECK POWER SUPPLY.
1. Turn ignition switch ``OFF''.
2. Disconnect mass air ¯ow sensor har-
ness connector.
3. Turn ignition switch ``ON''.
4. Check voltage between terminal
V1and ground with CONSULT or tester.
Voltage: Battery voltage
OK
cNG
Check the following.
+Harness connectors
M52,F7+Harness for open or
short between mass air
¯ow sensor and ECM
+Harness for open or
short between mass air
¯ow sensor and ECCS
relay
If NG, repair harness or
connector.
CHECK GROUND CIRCUIT.
1. Turn ignition switch ``OFF''.
2. Loosen and retighten engine ground
screws.
3. Check harness continuity between ter-
minal
V2and engine ground.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
OK
cNG
Check the following.
+Harness connectors
E106,M88+Harness connectorsM51,F6+Harness for open or
short between mass air
¯ow sensor and ECM
+Harness for open or
short between mass air
¯ow sensor and TCM
If NG, repair open circuit or
short to ground or short to
power in harness or con-
nectors.
CHECK INPUT SIGNAL CIRCUIT.
1. Disconnect ECM harness connector.
2. Check harness continuity between ter-
minal
V3and ECM terminalV35.
Continuity should exist.
If OK, check harness for short to
ground and short to power.
OK
cNG
Repair open circuit or short
to ground or short to power
in harness or connectors.
CHECK COMPONENT
(Mass air ¯ow sensor).
Refer to ``COMPONENT INSPECTION''
on next page.
OK
cNG
Replace mass air ¯ow sen-
sor.
Disconnect and reconnect harness con-
nectors in the circuits. Then retest.
Trouble is not ®xed.
Check ECM pin terminals for damage and
check the connection of ECM harness
connector. Reconnect ECM harness con-
nector and retest.
INSPECTION END
SEF713V
SEF736V
SEF676V
SEF737V
SEF738V
.
.
.
.
.
.
.
TROUBLE DIAGNOSIS FOR ``MASS AIR FLOW SEN'' (DTC 12)
Mass Air Flow Sensor (MAFS) (Cont'd)
EC-77

COMPONENT INSPECTION
Mass air ¯ow sensor
1. Start engine and warm it up to normal operating temperature.
2. Check voltage between ECM terminal
V35and ground under the
following condition.
Conditions Voltage V
Ignition switch ``ON'' (Engine stopped.) Less than 1.0
Idle (Engine is warmed-up sufficiently.) 1.0 - 1.7
2,500 rpm Approximately 2.1
Idle to about 4,000 rpm* 1.0 - 1.7 to Approx. 4.0
*: Check for linear voltage rise in response to increase to about 4,000 rpm in engine
speed.
3. If NG, remove mass air ¯ow sensor from air duct. Check hot
wire for damage and dust.
SEF739V
SEF740V
TROUBLE DIAGNOSIS FOR ``MASS AIR FLOW SEN'' (DTC 12)
Mass Air Flow Sensor (MAFS) (Cont'd)
EC-78