1987 NISSAN PULSAR jump start

92 Fuel and Engine Management

Installed view of the throttle body assembly showing
the location of the base idle adjusting screw. 1.6 liter
engine.
(7) Disconnect the IAC valve wiring connector
and slowly connect the vacuum supply hose to the
inlet manifold. Allow five seconds to elapse and note
the engine speed.
(8) If the engine speed is not to Specifications,
remove the plug from the throttle body housing on 1.6
liter engines, or the cap from the base idle adjusting
screw on 1.8 liter engines, and adjust the idle screw
until the engine speed is 625 rpm. (9) Stop the engine and connect the IAC valve
wiring connector. (10) On 1.8 liter engines, install a new cap to
the
base idle adjusting screw.
On 1.6 liter engines, seal the throttle stop screw
with silicone sealant and install the air cleaner assem-
bly.

(11) Erase the memory codes as previously de-
scribed.
(12) Start the engine and increase the speed to
3 000 rpm for 10 seconds to allow the idle air control
valve to reset.
5. FUEL SUPPLY COMPONENTS

Special Equipment Required:
To Check Fuel Pressure — 0-500 kPa pressure
gauge

NOTE: Before proceeding with any of the
operations in this section, refer to the Ser-
vice Precautions and Procedures heading.

TO DEPRESSURISE FUEL SYSTEM
(1) Lift the front edge of the rear seat cushion on
each side, slide the cushion forward and remove it
from the vehicle. (2) Disconnect the fuel pump wiring harness
connector.
When depressurizing the fuel system, remove the rear
seat cushion and disconnect the fuel pump wiring
connector.
(3) Start and run the engine until it stalls.
Operate the starter motor for 10 seconds to ensure
that the pressure has dissipated.
(4) Connect the fuel pump wiring connector and
install the rear seat cushion.
NOTE: Failure to depressurize the fuel sys-
tem when instructed may result in a fuel
spray and possible fire.

TO TEST FOR EXTERNAL LEAKS
(1) Connect a jumper lead between terminals G
and H on the diagnostic link connector.
(2) Switch the ignition On.
(3) Check for leaks at all hose connections and
joints between the fuel pump and the engine. (4) Switch the ignition Off and remove the
jumper lead from the diagnostic link connector.
(5) If renewal of a component is necessary,
depressurize the fuel system as previously described. (6) Use only hoses and clamps as specified by
the manufacturer.
TO CHECK FUEL PRESSURE

(1) Depressurize the fuel system as previously
described. (2) On 1.6 liter engines, remove the air cleaner
as described in this section under the Air Cleaner
Assembly heading. (3) On 1.8 liter engines, release the hose clamp
securing the fuel supply hos e to the fuel rail and
disconnect the hose. On 1.6 liter engines, release the hose clamp
securing the fuel supply hose to the rear throttle body
hose fitting and disconnect the hose.

(4) Using a suitable gauge, tee piece, short piece
of fuel hose and clamps, install the pressure
gauge
between the fuel supply ho se and the fuel rail on 1.8

Fuel and Engine Management 93
liter engines, or the throttle body hose fitting on 1.6
liter engines.

(5) Tighten all connectors securely. Check for
external leaks as previously described. (6) Start the engine and note the pressure while
the engine is idling.
(7) Switch the engine Off and check that the
residual pressure does not decrease.
If the fuel pressure is within Specifications and
does not decrease, the fuel system is in a serviceable
condition. Depressurize the fuel system and discon-
nect the pressure gauge.

If the fuel pressure is a bove Specifications proceed
to operation (9).

If the fuel pressure is below Specifications proceed
to the following operation.

If the fuel pressure decreases, an internal leak is
indicated. Proceed to the following heading and carry
out the test procedure.


Testing the fuel system pressure using a pressure
gauge. 1.8 liter engine.
NOTE: There may be a small initial de-
crease in pressure when the engine is
switched Off This is acceptable and does not
indicate a fault in the system.

(8) If the fuel pressure is below Specifications
proceed as follows:

(a) Check the fuel lines for blockages and kinks
or a blocked fuel filter or fuel pump pickup strainer. (b) If no fault can be found in the previous
checks, on 1.8 liter engines clamp the fuel return hose
at the fuel rail. On 1.6 liter engines, clamp the hose that is
connected to the front throttle body hose fitting.

(c) Connect a jumper lead between terminals G
and H on the diagnostic link connector and switch the
ignition On.

NOTE: Do not operate the fuel pump for
longer than is necessary to obtain a pressure
reading.

If the fuel pressure is less than 270 kPa on 1.8 liter
engines or 90 kPa on 1.6 liter engines, renew the fuel
pump.

If the fuel pressure is more than previously
specified, renew the pressure regulator assembly on
1.8 liter engines or the pressure regulator diaphragm
on 1.6 liter engines.

(9) If the fuel pressure in operation (6) is above
Specifications, proceed as follows:

(a) On 1.8 liter engines, disconnect the fuel
return hose from the pressure regulator outlet.

On 1.6 liter engines, disc onnect the fuel return
hose from the front throttle body hose fitting.

(b) Connect a suitable length of fuel hose to the
pressure regulator or the front throttle body hose
filling and place the opposite end of the hose into a
petroleum resistant container. (c) Connect a jumper lead between terminals G
and H on the diagnostic link connector and switch the
ignition On. If the fuel pressure is 230-270 kPa on 1.8 liter
engines or 62-90 kPa on 1.6 liter engines, locate and
remove the restriction in the fuel return hose or pipe.

If the fuel pressure is more than previously
specified, renew the pressure regulator assembly on
1.8 liter engines or the pressure regulator diaphragm
on 1.6 liter engines.

TO TEST FOR INTERNAL FUEL LEAKAGE
Check the residual fuel pressure as previously
described.

If the pressure has decreased it is an indication of
an internal leak. With the pressure gauge still at-
tached, proceed as follows:

(1) Switch the ignition On to pressurize the fuel
system.
(2) As the pressure begins to decrease clamp the
fuel supply hose shut. If the pressure remains steady
the fuel pump may be consid ered faulty and should be
renewed as described later in this section. (3) If the pressure continues to decrease switch
the ignition On after it has been Off at least 10
seconds. As the pressure begi ns to decrease clamp the
fuel return hose shut. If the pressure remain steady on 1.8 liter engines,
renew the pressure regulator. If the pressure continues
to decrease, leaking inject ors are indicated. Remove
the injectors as described later in this section to locate
the leaking injectors.

If the pressure remains stea dy on 1.6 liter engines,
renew the pressure regulator diaphragm as described
later in this section. If the pressure continues to
decrease remove the injector and renew the O ring
seals as described later in this section. If this fails to
rectify the fault remove the injector and clean or
renew the injector as necessary.

\(V2 Fuel and Engine Management


View of the IAC valve removed from the engine. Dimension A must not exceed 28 mm.
(3) Lubricate the IAC valve O ring with engine
oil and install the IAC valve. Tighten the retaining
screws securely.

(4). Install the IAC valve wiring connector and
the negative battery terminal.

(5) On 1.6 liter engines, install the air cleaner
assembly as previously described. (6) Run the engine until normal operating tem-
perature and idle speed are attained.
NOTE: Several minutes may elapse before
the normal idle speed is attained.

(7) Hold the throttle open at approximately
3 000 rpm for 10 seconds to reset the IAC valve.

MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSOR

To Test - Codes 33 and 34
NOTE: The following test procedure
assumes that fault codes 33 or 34 have
been
displayed during the self diagnosis test
pro-
cedure. If no codes have been displayed
but
the operation of the MAP sensor is suspect,
begin the test procedure at operation (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 code 34 is displayed, remove the jumper lead
from the diagnostic link connector, erase the self
diagnosis codes and proceed to operation (7).

If code 33 is displayed, remove the jumper lead
from the diagnostic link connector, erase the self
diagnosis code memory and proceed to operation (4).

If no codes are displayed, but codes 33 or 34
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.
(c) Check the vacuum hose to the MAP sensor
for deterioration or restriction.
(4) Disconnect the wiring connector from the
MAP sensor. (5) Start and run the engine at idle speed for 60
seconds or until the ECM warning lamp lights. (6) 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 code 33 is displayed, measure the voltage at
the
MAP sensor wiring connector terminal B with a
voltmeter to earth. Renew the control unit if the
voltage is less than 1 volt.

If the voltage is more than 1 volt, check the
wiring
harness for a short to voltage between terminal B and
the control unit wiring connector terminal Cll.
Repair or renew the wiring harness as necessary.

If code 34 is displayed, proceed as follows:
(a) Check for a restricted or leaking MAP sensor
vacuum hose.
(b) Check the wiring harness for continuity and
shorts between terminals A on the MAP sensor
connector and terminal A11 on the control unit wiring
connector. Repair or renew the wiring harness as
necessary.
If no faults are indicated in the above two checks,
proceed to operation (15).

(7) Disconnect the wiring connector from the
MAP sensor and connect a jumper lead between
terminals B and C on the wiring connector. (8) Start and run the engine at idle speed for 60
seconds or until the ECM warning lamp lights. (9) 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 code 33 is displayed, proceed to operation (15).
If code 34 is displayed, proceed as follows.

Location of the MAP sensor. Inset shows the terminal
identification.

106 Fuel and Engine Management
on the pickup coil wiring connector. The resistance
should be 500-1 500 ohms.

If the resistance is not as specified in either of the
above tests, renew the pickup coil.

(4) Remove the retaining spring from the dis-
tributor drive coupling.
(5) Using a pin punch, remove the drive pin
from the shaft. (6) Remove the drive coupling, washer, tang
washer and thrust spring from the shaft. (7) Remove the rotor and sh aft from the distrib-
utor housing. (8) Remove the retainer from the distributor
housing and withdraw the pickup coil. (9) Remove the retaining sc rews and remove the
control module from the distributor body. (10) Carefully lever the stationary pole from the
housing using a suitable screwdriver. Assembly is a reversal of the dismantling proce-
dure with attention to the following points:

(1) Ensure that the mating surfaces of the dis-
tributor housing and the control module are clean.
(2) Apply a silicone heat sink compound to the
surfaces between the control module and the distrib-
utor housing.
IGNITION COIL

To Test
(1) Disconnect the grey wiring connector and the
black wiring connector from the ignition coil in that
order. (2) Measure the resistance between coil terminal
I and the coil body. There should be a high resistance. (3) Measure the resistance between coil termi-
nals 2 and 4. There should be a low resistance. (4) Measure the resistance between coil terminal
3 and the high tension termin al. The resistance should
be other than infinity.
If any of the tests indicate a fault, renew the
ignition coil.

To Remove and Install
(1) Disconnect the negative battery terminal.
(2) Disconnect the grey wiring connector and the
black wiring connector from the ignition coil in that
order. Disconnect the high tension lead. (3) Remove the coil mounting bracket retaining
bolts and remove the coil and bracket from the
engine. Installation is a reversal of the removal procedure.

ELECTRONIC SPARK TIMING
To Test - Code 42

(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 code 42 is displayed, proceed to operation (4).

If code 42 is not displayed, but was displayed
when the self diagnosis test procedure was originally
performed, an intermittent fault is indicated. Proceed
as follows:

(a) Check for faulty wiri ng connections. Check
that all wiring connectors are clean and secure.
(b) Check that all earth wires are secure.
(4) With the ignition switched Off, disconnect
the control unit wiring connectors. (5) With the ignition switched On, measure the
resistance between the contro l unit wiring connector
terminal D4 and a good earthing point. The resistance
should be less than 500 ohms.
If the ohmmeter reading is as specified, check the
wiring harness between the distributor 4 pin wiring
connector terminal D and the control unit wiring
connector terminal D4 for continuity. Repair or
renew the wiring harness as necessary. Also ensure
that the distributor 4 pin wiring connector is making
good contact when connected to the distributor.

If no fault can be found, renew the ignition
control module.

If the resistance is as specified proceed as follows.
(6) With the lead of a test lamp connected to the
positive battery terminal, backprobe the control unit
wiring connector terminal D5.

If the test lamp does not light, proceed to
operation (7).

If the test lamp lights, disconnect the 4 pin wiring
connector from the distributor. If the test lamp
remains illuminated check the wiring harness between
the distributor 4 pin wiring connector terminal B and
the control unit wiring connector terminal D5 for
shorts to earth. Repair or renew the wiring harness as
necessary. If the test lamp extinguishes, renew the
ignition system control module.

(7) Connect an ohmmeter between the control
Installed view of the ignition coil showing the coil
terminal identification.

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 ne gative 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 rela y 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 pu mp 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 contro l 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 connect or. 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 wiri ng 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 d e g C ................................................. 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 th e 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 se lf 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 co nnector and proceed to
operation (8). .

(3) With the engine id ling, 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 wiri ng 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 connect or. 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, pr oceed 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, pr oceed to operation (24).
If the test lamp does not light, check the wiring
harness between the throt tle position sensor wiring
connector terminal B and the control unit wiring
connector terminal D2 fo r 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 connecto r 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 sp eed 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 positi on 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 wiri ng 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 s hould 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.