1987 NISSAN PULSAR sensor

90 Fuel and Engine Management
To identify the code number, count the number of
times the ECM warning lamp flashes. Each fault code
comprises two groups of flashes separated by a 1.2
second pause. The first group represents tens and the
second group represents single units. For example 1
flash followed by a 1.2 second pause followed by 4
flashes would be code number 14. Similarly 4 flashes
followed by a 1.2 second pause followed by 2 flashes
would be code number 42.

The code will be displayed three times. If more
than one fault code is present, the self diagnosis
system will indicate each one in numerical order, with
a 3.2 second pause between each code, and then
repeat the sequence.

The fault codes can be identified as follows:
CODE NUMBER FAULT AREA
12 Satisfactory operation
13 Oxygen sensor open circuit
14 Coolant temperature sensor circuit (voltage low)
15 Coolant temperature sensor circuit (voltage high)
21 Throttle position sensor circuit (voltage high)
22Throttle position sensor circuit (voltage low)
23MAT sensor circuit (voltage' high) 1.8 liter engine
only
24 Vehicle speed sensor circuit
25 MAT sensor circuit

(voltage low) 1.8 liter engine
only
33 MAP sensor circuit

(voltage high)
34MAP sensor circuit (voltage low)
42 Electronic spark timing circuit
44
Oxygen sensor circuit

(lean exhaust)
45Oxygen sensor circuit (rich exhaust)
51 Mem-Cal
55 Control unit input circuits
Test Procedure
(1) Perform the following checks:

(a) Ensure that the battery voltage is above 11
volts. (b) Ensure that the throttle valve is fully closed.
(c) Place the transaxle in neutral.
(d) Ensure that the air conditioner, fan, tights
and all other accessories are switched off.
(2) Turn the ignition On and confirm that the
ECM warning lamp on the instrument cluster is
illuminated but not flashing.

If code 55 is displayed, refer to the Control Unit
heading, perform the circuit test procedure and rectify
the cause of the code before proceeding.

If the ECM warning lamp flashes codes other than
code 55, check the wiring harness between the diag-
nostic link connector terminal B and the control unit
wiring connector terminal A9 for shorts. Repair or
renew the wiring harness as necessary.

If no fault can be found, renew the control unit.
If the ECM warning lamp does not illuminate,
proceed as follows:

(a) Check the METER fuse located in the fuse
panel adjacent to the steering column and the fusible
links located in the fusible link connecting block at the
rear of the battery. Renew the fuse or fusible links as
necessary. (b) Check the wiring harness to the instrument
cluster. Repair or renew the harness. (c) Check the Check Engine lamp bulb. Renew if
necessary. (d) Check the EGI relay. Renew as necessary.
(3) Connect a jumper lead across terminals A
and B on the diagnostic link connector located under
the front passengers seat above the control unit.
(4) Note the codes indicated by the flashing
ECM warning lamp.
If code 12 is displayed, the system is operating
correctly.

If codes other than code 12 are displayed, refer to
the component or circuit test procedure under the
appropriate heading as indicated by the code number.

If more than one code is being displayed, test each
indicated fault working in the order of display of the
code numbers.

(5) After completing the self diagnosis test pro-
cedure, remove the jumper lead from the diagnostic
link connector. (6) After repairing or renewing the necessary

View showing the location of the diagnostic link
connector. Passengers seat removed for clarity.
Inset shows the diagnostic link connector terminal identification.

Fuel and Engine Management 99
stalled on each side of the air cleaner mounting
bracket when installing the mounting bolts.

(2) If renewing the element, ensure that the
specified element is installed and is correctly seated in
the air cleaner housing. (3) Ensure that the air intake hose clamps are
tightened securely.
To Remove and Install — 1.6 Liter Engine

(1) Disconnect the negative battery terminal.
(2) Remove the nuts and washers retaining the
air cleaner to the throttle body assembly. (3) Release the top cover retaining clips and
remove the top cover and the air cleaner element.
Remove the air cleaner retainer from the throttle body
bolts. (4) Disconnect the engine vent hose from the air
cleaner support clamp. (5) Slightly raise the air cleaner and tilt it
towards the windscreen. Disc onnect the engine vent
hose and the temperature sensor vacuum hose from
the underside of the air cleaner. (6) Remove the air cleaner housing from the
engine.

Dismantled view of the air cleaner.
(7) Thoroughly clean the air cleaner housing and
top cover and check for cracks or damage that would
allow unfiltered air to enter the engine. Renew any
components as necessary.

Installation is a reversal of the removal procedure
with attention to the following points:

(1) Inspect the air cleaner base gasket. Renew if
necessary. (2) Connect the engine vent hose and the tem-
perature sensor vacuum hose. (3) Install the air cleaner ensuring that the hot air
inlet tube is located correc tly between the exhaust heat
shield and the air cleaner housing. (4) When installing the top cover retaining nuts,
hand tighten only. THROTTLE BODY ASSEMBLY

To Remove and Install — 1.8 Liter Engine
(1)
Disconnect the negative battery terminal.
(2) Release the air intake hose clamp and dis-
connect the air intake hose from the throttle body. (3) Unclip the actuating rod from the throttle
lever using a small screwdriver under the ball socket if
necessary.
(4) Mark the throttle body vacuum hoses with
quick drying paint or similar and disconnect the hoses
from the throttle body. Disconnect the engine vent
hose from the throttle body. (5) Disconnect the wiring connectors from the
throttle position sensor and the IAC valve.
(6) Remove the retaining nuts and withdraw the
throttle body and gasket.
View of the throttle body and actuating rod. The rod
length must be set so that dimension A - 8—9 mm for
automatic transaxle models and 3—4 mm for manual
transaxle models.

View of the throttle body and associated components.

100 Fuel and Engine Management
Installation is a reversal of the removal procedure
with attention to the following points:

(1) Ensure that all throttle body passages are
clean. Blow out with compressed air if necessary. (2) Install the throttle body to the inlet
manifold
using a new gasket and tighten the retaining nuts to
the specified torque. (3) Connect the vacuum hoses to the throttle
body in the positions previously marked. (4) Clip the actuating rod to the throttle body
lever. Check the dimensions shown in the illustration
and adjust the rod length if necessary.
(5) Check the adjustment of the throttle cable as
described later in this section.
(6) Connect the air intake hose and tighten the
hose clamps securely.
To Remove and Install — 1.6 Liter Engine

(1) Depressurize the fuel system as previously
described. (2) Disconnect the negative battery terminal.
(3) Remove the air cleane r assembly and base
gasket as previously described. (4) Mark the fuel supply and return hoses,
release the clamps and disconnect the hoses from the
throttle body assembly. (5) Disconnect the injector, throttle position
sensor and the IAC valve wiring connectors. Remove
the injector wiring harness from the throttle body
assembly and place it to one side.
(6) Mark and disconnect the vacuum hoses from
the throttle body assembly. (7) On automatic transaxle models, disconnect
the kickdown actuating rod from the throttle linkage.
(8) Slide the outer throttle cable from the
mounting bracket, rotate the throttle linkage and disconnect the inner throttle cable from the throttle
linkage.

(9)
Remove the bolts retaining the throttle body
assembly to the inlet manifold and remove the
assembly and the gasket from the engine. (10) If necessary remove the retaining screws and
remove the fuel meter assembly, the IAC valve and
the throttle position sensor from the throttle body
assembly. Installation is a reversal of the removal procedure
with attention to the following points:

(1) If removed, install the fuel meter assembly,
the throttle position sensor and the IAC valve as
described under the relevant headings. (2) Install the throttle body assembly to the inlet
manifold using a new gasket and tighten the retaining
bolts to the specified torque. (3) Connect the vacuum ho ses to the throttle
body using the marks made on removal to ensure
correct installation. (4) On automatic transaxle models, connect the
kickdown actuating rod to the throttle linkage.
(5) Install the throttle cable and check the adjust-
ment as described later in this section.
INLET MANIFOLD

To Remove and Install
To remove and install the inlet manifold, refer to
the relevant heading in the Engine section.

IDLE AIR CONTROL (IAC) VALVE
To Test

(1) Connect an accurate tachometer to the en-
gine. (2) With the engine at normal operating temper-
ature and all accessories switched Off, note the idle
speed.
(3) With the ignition switched Off, disconnect
the IAC valve wiring connector. (4) Start the engine and check the idle speed.
If the idle speed is the same as that noted in

operation (2) proceed to operation (7).
If the idle speed is higher than noted in operation
(2) proceed as follows.

(5) With the ignition switched Off, connect the
IAC valve wiring connector.

(6) Start the engine and check the idle speed.
If the idle speed is not the same as that noted in

operation (2) proceed to operation (7).
If the idle speed is the same as noted in operation
(2) the IAC valve is operating correctly. However, if
the engine is not idling correctly carry out the
following checks.

(a) Check the air inlet system for vacuum leaks.
NOTE: Any vacuum leak will cause a fast
idle.

View of the throttle body assembly showing the loca-
tion of the base idle adjusting screw. 1.8 literengine.

Fuel and Engine Management 101


Location of the idle air control (IAC) valve. Inset shows the terminal identification.
(b) Check for a binding throttle cable, throttle
shaft or throttle position sensor. (c) Check the coolant temperature sensor resis-
tance as described later in this section. (d) Ensure that the battery terminals and the
engine earth terminals are clean and secure.
(e) Check the operation of the Park/Neutral
switch and the transaxle as described in the Automatic
Transaxle section under the Neutral Safety Switch
heading. (f) Check the spark plug gaps as described in the
Engine Tune-up section.
(g) Check the base idle speed adjustment.
(h) Check the fuel pressure and check the system
for leaks as described previously.

(I) Check the alternator voltage output as de-
scribed in the Electrical System section to ensure that
it is between 9-17 volts.

(j) Remove the IAC valve and check the bore in
the throttle body for dirt or damage.

(7) Stop the engine, switch the ignition On and
connect a jumper lead between terminals A and B on
the diagnostic link connector. (8) Disconnect the wiring connector from the
IAC valve.
(9) Check for voltage at each of the terminals on
the IAC valve wiring connector using a test lamp. If the test lamp flashes at each terminal, correct
operation of the wiring and control unit is indicated.
check for faulty IAC valve terminals. If no fault is
found renew the IAC valve.

If the test lamp is a steady light at one or more
terminals, proceed to operation (10).

If the test lamp does not flash at one or more of
the terminals proceed as follows:

(a) Check the circuit with no voltage for shorts
and for continuity between the IAC valve and the
control unit. Repair or renew the wiring harness as
necessary.
(b) Measure the resistance across the IAC valve
terminals A and B, and across terminals C and D. The resistance should be more than 30 ohms.

If the resistance is not as specified, renew the IAC
valve.

If the resistance is as specified, check for faulty
wiring connector terminals on the IAC valve and the
control unit. If no fault is found, renew the control
unit

(10) Switch the ignition Oft' and disconnect the
control unit wiring connectors. (11) Switch the ignition On and check the IAC
connector with the test lamp again. If the light is stilt
steady on one or more terminals there is a short
circuit to voltage in the wiring harness. Repair or
renew as necessary. (12) If the light is not on, check for faulty IAC
valve terminals. If no fault is found renew the IAC
valve.
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 wiring connector from the
IAC valve. (4) Remove the IAC valve retaining screws and
withdraw the IAC valve and O ring.

View of the IAC valve removed from the throttle body
assembly. 1.6 liter engine.
(5) Clean the IAC sealing surfaces to ensure
proper operation.

Installation is a reversal of the removal procedure
with attention to the following points:

(1) When installing a new IAC valve ensure that
the part number is correct as the valve is not
interchangeable between the 1.8 and 1.6 liter engines.
(2) Measure the length of the pintle extension as
shown in the illustration. If necessary push the pintle
in by exerting firm thum b pressure with a slight
rocking motion.
NOTE: Installing (he IAC valve with the
pintle protruding too far can damage the
valve.

\(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.

Fuel and Engine Management 103
(10) Remove the jumper lead from the MAP
sensor wiring connector and measure the voltage
across terminals A and C on the MAP sensor wiring
connector.

If the voltage is below 4 volts, proceed to opera-
tion (12).

If the voltage is 4-6 volts, proceed as follows.
(11) With the ignition switched Off, disconnect
the wiring connectors from the control unit and check
the wiring harness for contin uity and shorts between
MAP sensor wiring connector terminal B and control
unit wiring connector terminal C11. Check the wiring
connectors for faults. Repair or renew the wiring
harness as necessary.

If no fault is found, renew the control unit and
retest for fault codes.

(12) Disconnect the wiring connector from the
throttle position sensor. (13) Measure the voltage across terminals A and
C on the MAP sensor wiring connector.
If the voltage is 4-6 volts, renew the throttle
position sensor as describe d later in this section.
If the voltage is below 4 volts, proceed as follows.

(14) With the ignition switched Off, disconnect
the wiring connectors from the control unit and check
the wiring harness for contin uity and shorts between
the MAP sensor wiring connector terminal C and
control unit wiring connector terminal C14. Check the
wiring connectors. Repair or renew the wiring harness
as necessary.

If no fault is found, renew the control unit and
retest for fault codes.

(15) Test the MAP sensor as follows:
(a) With the ignition switched On and the MAP
sensor wiring connector connected, measure the volt-
age across terminals A an d B by backprobing the
MAP sensor wiring connector. The voltage should be
as follows:

ALTITUDE VOLTAGE
Below 305 m .......................................... 3.8-5.5 volts
305-610 m ............................................. 3.6-5.3 volts
610-914 m ............................................. 3.5-5.1 volts
914-1 219 m .......................................... 3.3-5.0 volts
1 219-1 524 m ...................................... 3.2-4.8 volts
1 524-1 829 m ...................................... 3.0-4.6 volts
1 829-2 133 m ...................................... 2.9-4.5 volts
2 133-2 438 m ....................................... 2.8-4.3 volts
2 438-2 743 m ...................................... 2.6-4.2 volts

2 743-3 048 m ...................................... 2.5-4.0 volts
If the voltage is not as specified, renew the MAP
sensor.

(b) If the voltage is as specified, apply a 34 kPa
vacuum to the MAP sensor using a vacuum pump.
The voltage should be 1.2-2.3 volts lower than that
measured in operation (a).

If the voltage is not as specified, renew the MAP
sensor.

If no fault is found, check the vacuum supply hose
for restriction, leakage or correct installation.

To Remove and Install
(1) Disconnect the negative battery terminal.
(2) Disconnect the MAP sensor wiring connec-
tor and the vacuum hose. (3) Remove the retaining sc rews and remove the
MAP sensor from the vehicle.
Installation is a reversal of the removal procedure
with attention to the following points:

(1) If a new MAP sensor is to be installed ensure
that the colored insert inside the connector cavity
matches the color of the wiring connector.
(2) Ensure that the wiri ng connector and the
vacuum hose are connected securely.
THROTTLE CABLE
To Remove and Install

(1) On 1.6 liter engines, remove the air cleaner
assembly as previously described.
(2) Slide the outer throttle cable from the
mounting bracket, rotate the throttle linkage and
disconnect the inner throttle cable from the throttle
linkage. (3) Disconnect the throttle cable from the retain-
ing clamps in the engine compartment. (4) Disconnect the plastic re tainer from the top
of the throttle pedal and disengage the inner throttle
cable from the pedal. (5) Remove the bolts securing the throttle cable
to the bulkhead and withdraw the throttle cable. Installation is a reversal of the removal procedure.

To Adjust
(1) On 1.6 liter engines, remove the air cleaner
assembly as previously described.
(2) Remove the snap ring securing the outer
throttle cable to the insulator in the mounting bracket.
View showing the throttle cable adjustment point. 1.8
liter engine.

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