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Nissan PULSAR N13 Series / ASTRA LD Series. Manual - part 27

Fuel and Engine Management

109

Diagram showing the identification of the relay and the

relay connector terminals.

To Test Relay Circuits

(1) Remove the relevant relay as previously

described and connect the negative battery terminal.

(2) Connect a test lamp to earth and probe the

fuel pump relay connector terminal C or the EGI relay
connector terminal A. With the ignition switched On
the test lamp should light.

If the test lamp does not light check the fuel pump

fuse and the wiring harness for continuity between the
ignition switch and the fuel pump relay connector
terminal C or EGI relay connector terminal A.

(3) With the ignition remaining switched On,

connect the test lamp between the fuel pump relay
connector terminals C and B or the EGI relay
connector terminals A and B.

If the test lamp does not light, repair the open

circuit between terminal B and earth.

(4) When checking the EGI relay circuit, pro-

ceed to operation (9).

When checking the fuel pump relay circuit pro-

ceed as follows.

(5) Probe the relay connector terminal A with a

test lamp to earth. Switch the ignition On and note the
test lamp.

If the test lamp lights for 2 seconds, proceed to

step (7).

If the test lamp does not light as specified, proceed

as follows.

(6) Switch the ignition Off and backprobe the

control unit wiring connector terminal A1 with a test
lamp to earth. With the ignition switched On the test
lamp should light as previously described.

If the test lamp does not light as described, renew

the control unit.

If the test lamp does light as described, locate the

open circuit or short in the wiring harness between the
control unit wiring connector terminal Al and the
relay connector terminal A. Repair or renew the
wiring harness as necessary.

(7) With the ignition switched Off connect a

jumper lead between the relay connector terminals C
and D.

(8) Switch the ignition On and listen for the

operation of the fuel pump. It should be possible to
feel vibrations in the fuel return hose.

If the fuel pump is operating, the fuel pump relay

circuit can be considered serviceable.

If the fuel pump is not operating, check the wiring

harness for continuity between the fuel pump wiring
harness connector, the fuel pump relay connector
terminal D and earth. If no fault can be found, renew
the fuel pump.

(9) Probe the relay connector terminal C with a

test lamp to earth. The test lamp should light.

If the test lamp does not light, locate the open

circuit between the battery and terminal C. Check the
fusible link which is located third from the front in the
fusible link connecting block.

(10) Connect a jumper lead between the relay

connector terminals C and D and backprobe the
control unit wiring connector terminal A6 with a test
lamp to earth.

If the test lamp lights, the EGI relay circuit can be

considered serviceable.

If the test lamp does not light locate the open

circuit between the control unit wiring connector
terminal A6 and the relay connector terminal D.
Repair or renew the wiring harness as necessary.

COOLANT TEMPERATURE SENSOR

To Test — Codes 14 and 15

(1) Erase the self diagnosis code memory as

previously described.

(2) Start and run the engine at idle speed for 60

seconds or until the ECM warning lamp lights.

(3) Stop the engine, switch the ignition On and

connect a jumper lead between terminals A and B on
the diagnostic link connector. Note any fault codes
displayed.

If codes 14 or 15 are displayed, proceed to

operation (4).

If codes 14 or 15 are not displayed, but were

displayed when the self diagnosis test procedure was

View showing the location of the coolant temperature

sensor. 1.6 liter engine.

110

Fuel and Engine Management

originally performed, an intermittent fault is indi-
cated. Proceed as follows:

(a) Check for faulty wiring connections. Check

that all wiring connectors are clean and secure.

(b) Check that all earth wires are secure.

(4) Disconnect the wiring connector from the

coolant temperature sensor.

(5) With the ignition switched On, measure the

voltage across the terminals on the coolant tempera-
ture sensor wiring connector. The voltage should be
4-6 volts.

If the voltage is below 4 volts, proceed to opera-

tion (9).

If the voltage is as specified, proceed as follows.

(6) Remove the coolant temperature sensor

from the vehicle.

(7) Connect an ohmmeter to the coolant temper-

ature sensor terminals.

(8) Immerse the meta1 end of the coolant

tem-
perature sensor in a 50/50 mixture of glycol and iced
water at a temperature of 0 deg C. The resistance
should be 6 000 ohms.

Slowly heat the mixture and measure the resis-

tance of the coolant temperature sensor at the follow-
ing temperatures. Compare the results with the spec-
ified values:

0 degC................................................. 6 000 ohms

20 deg C.................................................. 2 500 ohms

30 deg C.................................................. 1 800 ohms

40 deg C.................................................. 1 200 ohms

70 deg C.......................................................450 ohms

90 degC .......................................................250 ohms

100 deg C.....................................................190 ohms

110 deg C.....................................................110 ohms

If the resistances obtained are not as specified at

any of the given temperatures, renew the coolant
temperature sensor and retest for fault codes.

(9) Disconnect the control unit wiring connec-

tors.

(10) Check the wiring harness for shorts and

continuity between the coolant temperature sensor
wiring connector terminals and the control unit wiring
connector terminals C10 and D2. Repair or renew the
wiring harness as necessary.
Also check the control unit terminals for damage.
If no fault is found, renew the control unit and
retest for fault codes.

To Remove and Install

(1) Disconnect the negative battery terminal.
(2) Disconnect the wiring connector from the

coolant temperature sensor.

(3) Drain the coolant as described in the Cooling

and Heating Systems section to a level below the
sensor.

(4) Unscrew the sensor from the thermostat

housing.

Installation is a reversal of the removal procedure

with attention to the following points;

(1) Apply Loctite 675 or a similar conductive

sealer to the threads of the sensor. Tighten the sensor
to the specified torque.

(2) Fill the cooling system with the correct

mixture of water and inhibitor as described in the
Cooling and Heating Systems section.

(3) Ensure that the wiring connector is clean and

secure.

THROTTLE POSITION SENSOR

To Test - Codes 21 and 22

NOTE: The following test procedure as-
sumes that fault codes 21 or 22 have been
displayed during the self diagnosis test pro-
cedure. If no codes have been displayed but
the operation of the throttle position sensor
is suspect, begin the test procedure at oper-
ation (24).

(1) Erase the self diagnosis code memory as

previously described.

(2) Start and run the engine at idle speed for 60

seconds or until the ECM warning lamp lights.

If the engine will not start, disconnect the throttle

position sensor wiring connector and proceed to
operation (8). .

(3) With the engine idling, quickly increase the

engine speed to 3 000 rpm and return to idle.

If the ECM warning lamp remains illuminated,

proceed to operation (4).

If the ECM warning lamp extinguishes, an inter-

mittent fault is indicated. Proceed as follows:

(a) Check for faulty wiring connections. Check

that all wiring connectors are clean and secure.

(b) Check that all earth wires are secure.
(4) Stop the engine, switch the ignition On and

connect a jumper lead between terminals A and B on
the diagnostic link connector. Note any fault codes
displayed.

If codes 21 or 22 are displayed, proceed as

follows.

(5) Remove the jumper lead from the diagnostic

link connector.

(6) Erase the self diagnosis codes as previously

described.

(7) Disconnect the wiring connector from the

throttle position sensor.

If code 22 was displayed in operation (4), proceed

to operation (13).

If code 21 was displayed in operation (4), proceed

as follows.

(8) Start and run the engine at idle speed for 2

minutes or until the ECM warning lamp lights. If the
engine will not start, proceed to operation (11).

(9) Stop the engine, switch the ignition On and

connect a jumper lead between terminals A and B on

Fuel and Engine Management

111

Location of the throttle position sensor. Inset shows

the terminal identification.

the diagnostic link connector. Note any fault codes
displayed.

If code 21 is displayed, proceed to operation (11).

If code 22 is displayed, proceed as follows.

(10) Connect the lead of a test lamp to the

positive battery terminal and insert the probe into
terminal B on the throttle position sensor wiring
connector.

If the test lamp lights, proceed to operation (24).

If the test lamp does not light, check the wiring

harness between the throttle position sensor wiring
connector terminal B and the control unit wiring
connector terminal D2 for continuity. Repair or
renew the wiring harness as necessary and retest for
fault codes.

(11) With the ignition switched Off, disconnect

the control unit wiring connectors.

(12) With the ignition switched On, measure the

voltage at terminal C13 on the control unit wiring
connector.

If the voltage is less than 1 volt, check the wiring

harness for shorts between the throttle position sensor
wiring connector terminals C and A and the control
unit wiring connector terminals C13 and C14. Repair
or renew the wiring harness as necessary. If no fault
can be found, renew the control unit.

(13) Start and run the engine at idle speed.
(14) Connect a jumper lead across terminals A

and C on the throttle position sensor wiring connec-
tor.

(15) Stop the engine, switch the ignition On and

connect a jumper lead between terminals A and B on
the diagnostic link connector. Note any fault codes
displayed.

If codes 21 and 22 are displayed, proceed to

operation (24).

If code 22 only is displayed, proceed as follows.

(16) Remove the jumper lead from the throttle

position sensor wiring connector.

(17) Measure the voltage across the throttle posi-

tion sensor wiring connector terminals A and B.

If the voltage is below 4 volts, proceed to opera-

tion (20).

If the voltage is 4-6 volts, proceed as follows:

(18) With the ignition switched Off, disconnect

the control unit wiring connectors.

(19) Check the wiring harness between the con-

trol unit wiring connector terminal C13 and the
throttle position sensor wiring connector terminal C
for continuity and shorts. Repair or renew the wiring
harness as necessary and retest for fault codes.

If no fault is found, renew the control unit and

retest for fault codes.

(20) Disconnect the wiring connector from the

MAP sensor.

(21) Measure the voltage across the throttle posi-

tion sensor wiring connector terminals A and B.

If the voltage is 4 - 6 volts, renew the MAP sensor.
If the voltage is below 4 volts, proceed as follows.

(22) With the ignition switched Off, disconnect

the control unit wiring connectors.

(23) Check the wiring harness between the con-

trol unit wiring connector terminal C14 and the
throttle position sensor wiring connector terminal A
for continuity and shorts. Repair or renew the wiring
harness as necessary and retest for fault codes.

If no fault is found, renew the control unit and

retest for fault codes.

(24) With the ignition switched On, measure the

voltage at the control unit wiring connector terminal
C13.

If the voltage is 0.2-1.2 volts, proceed to opera-

tion (27).

If the voltage is 1.2-2.5 volts, proceed to opera-

tion (25).

If the voltage is over 2.5 volts, proceed as follows:

(a) Disconnect the wiring connector from the

throttle position sensor.

(b) Measure the voltage at the control unit

wiring connector terminal C13.

If the voltage is less than 1 volt, check the wiring

harness for continuity between the throttle position
sensor terminal B and the control unit wiring connec-
tor terminal D2. If the wiring harness is satisfactory,
renew the throttle position sensor.

(25) Check the base idle speed and adjust if

necessary as previously described.

(26) With the ignition switched On, measure the

voltage at the control unit wiring connector terminal
C13. The voltage should be 0.2-1.2 volts.

If the voltage is not as specified, renew the throttle

position sensor.

If the voltage is as specified, proceed as follows.

(27) With the ignition switched On, measure the

voltage at the control unit wiring connector terminal
C13 as the throttle is steadily opened to the wide open
throttle position. The voltage should increase steadily
with no sudden variations.

112

Fuel and Engine Management

If the voltage does not increase as specified, renew

the throttle position sensor.

If the voltage is as specified, proceed as follows.

(28) With the ignition switched On and the

throttle valve held fully open, measure the voltage at
control unit wiring connector terminal C13. The
voltage should be above 4 volts.

If the voltage is below 4 volts, renew the throttle

position sensor.

To Remove and Install

(1) Disconnect the negative battery terminal.
(2) On 1.6 liter engines, remove the air cleaner

assembly as previously described.

(3) Disconnect the throttle position sensor wir-

ing connector.

(4) Remove the throttle position sensor retain-

ing screws and remove the throttle position sensor
from the throttle body.

Installation is a reversal of the removal procedure

with attention to the following points:

(1) Ensure that the throttle valve is in the fully

closed position.

(2) Tighten the retaining screws securely and

install the wiring connector.

View of the throttle position sensor removed from the

throttle body assembly.

MANIFOLD AIR TEMPERATURE (MAT)
SENSOR - 1.8 LITRE ENGINE

To Test - Codes 23 and 25

(1) Erase the self diagnosis code memory as

previously described.

(2) Start and run the engine for 2 minutes or

until the ECM warning lamp lights.

(3) Stop the engine, switch the ignition On and

connect a jumper lead between terminals A and B on
the diagnostic link connector. Note any fault codes
displayed.

If codes 23 or 25 are displayed, proceed to

operation (4).

If codes 23 or 25 are not displayed but were

displayed when the self diagnosis test procedure was
originally performed, an intermittent fault is indi-
cated. Proceed as follows:

(a) Check for faulty wiring connections. Check

that all wiring connectors are clean and secure.

(b) Check that all earth wires are secure.

(4) Disconnect the wiring connector from the

MAT sensor.

(5) With the ignition switched On, measure the

voltage across the terminals on the MAT sensor wiring
connector. The voltage should be 4-6 volts.

If the voltage is below 4 volts, proceed to opera-

tion (9).

If the voltage is as specified, proceed as follows.

(6) Remove the MAT sensor from the engine.
(7) Connect an ohmmeter to the MAT sensor

terminals.

(8) Immerse the metal end of the MAT sensor in

a container of iced water at a temperature of 4 deg C.
The resistance should be 7 500 ohms.

Slowly heat the water and measure the resistance

of the MAT sensor at the following temperatures.
Compare the results with the specified values:

20 deg C.................................................. 3 400 ohms

38 deg C....................................................1 800 ohms

70 degC...................................................... 450 ohms

100 deg C.................................................... 185 ohms

If the resistances obtained are not close to the

specified figures at any of the given temperatures,
renew the MAT sensor and retest for fault codes.

(9) Disconnect the control unit wiring connec-

tors.

(10) Check the wiring harness between the MAT

sensor wiring connector and the control unit wiring
connector terminals C12 and A11 for shorts and
continuity. Also check the control unit terminals for
damage.

Repair or renew the wiring harness as necessary.
If no fault is found, renew the control unit and
retest for fault codes.

To Remove and Install

(1) Disconnect the negative battery terminal.

Installed view of the MAT sensor. 1.8 liter engine.

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