1987 NISSAN PULSAR display

Fuel and Engine Management 107
unit wiring connector terminal D4 and a good earth-
ing point.

(8) With the lead of a test lamp connected to the
positive battery terminal, backprobe the control unit
wiring connector terminal D5. As the test lamp probe
touches the terminal, the ohmmeter reading should
change from less than 500 ohms to over 5 000 ohms.

If the ohmmeter reading is not as specified,
proceed to operation (9).

If the ohmmeter reading is as specified, switch the
ignition Off and install the control unit wiring connec-
tors. Run the engine for 60 seconds or until the ECM
warning lamp lights and check for fault codes.

If code 42 is displayed renew the control unit.
If code 42 is not displayed, check the wiring
harness for continuity or sh orts between the control
unit wiring connector terminals D4 and D5 and the
distributor 4 pin wiring connector terminals D and B.

(9) Disconnect the 4 pin wiring connector from
the distributor.

(10) Check for continuity between the control
unit wiring connector termin al D4 and a good earth-
ing point. There should be no continuity.

If the continuity is not as specified, check the
wiring harness between the distributor 4 pin wiring
connector terminal D and the control unit wiring
connector terminal D4 for shorts to earth. Repair or
renew the wiring harness as necessary.

If the continuity is as specified, check the wiring
harness between the distributor 4 pin wiring connec-
tor terminal B and the control unit wiring connector
terminal D5 for continuity. Repair or renew the
wiring harness as necessary. If no fault is found, renew
the ignition system control module.

CONTROL UNIT
To Test Input Circuits — Code 55
(1) Switch the ignition On with the engine
stopped and note the ECM warning lamp. (2) If a steady light is showing, proceed to
operation (3). If code 55 is displayed, proceed as follows:

(a) Switch the ignition Off and disconnect the
wiring connector from the control unit.
(b) Switch the ignition On and measure the
voltage at the wiring connector on terminals C10,
C I 1 , C12, C13 and A9. Disregard terminal C12 on
1.6 liter engines. (c) If there is voltage at any of the terminals
tested above, a faulty wi ring harness is indicated.
Repair the short circuit to voltage and return to
operation (1). (d) If there is no voltage at any of the terminals
tested, a faulty control unit is indicated. Renew the
control unit and return to operation ( 1 ) . (3) Connect a jumper lead between terminals A
and B on the diagnostic link connector and note if
code 55 is displayed.

If code 55 is displayed, an intermittent fault is
indicated. Switch Off the engine, erase the self diag-
nosis codes and run the engine for 2 minutes. Return
to operation (1 ) and repeat the test procedures.

If code 55 continues to return, renew the control
unit.

To Remove and Install
(1) Disconnect the negative battery terminal.
(2) Slide the passengers front seat to the rear-
most position and working under the seat, disconnect
the control unit wiring connectors. (3) Disengage the plastic control unit cover from
the mounting plate and remove the control unit from
the vehicle. (4) If necessary, remove the screws retaining the
Mem-Cal cover to the control unit.
(5) Release the Mem-Cal unit retaining clips,
grasp the Mem-Cal unit at each end and remove it
from the control unit. Installation is a reversal of the removal procedure
with attention to the following points:

(1) When installing the Mem-Cal unit, align the
notches in the Mem-Cal with those in the control unit
and push on each end of the Mem-Cal unit. Do not
push on the middle section of the Mem-Cal unit.

View of the control unit with the Mem-Cal unit re-
moved.

108 Fuel and Engine Management


Installed view of the control unit with the passengers seat removed.
(2) Secure the Mem-Cal unit retaining clips.
Ensure that the clips locate into the Mem-Cal unit. (3) When installing a new control unit, transfer
the identification and bar code label to the new
control unit. (4) Ensure that the control unit wiring connec-
tors are securely installed to the control unit. (5) Activate the self diagnosis codes. If code 51
is displayed or the Check Engine warning lamp is
constantly illuminated, the Mem-Cal unit is not fully
installed. If the Mem-Cal uni t is installed correctly, a
fault in the Mem-Cal unit is indicated. Renew the
Mem-Cal unit as previously described.
To Check Power Supply and Earth Circuit

(1) Disconnect the control unit wiring connec-
tors and check for voltage at terminals B1 and C16.

If there is no voltage check the fusible link which
is located third from the front in the fusible link
connecting block. If the fu sible link is serviceable,
repair the open circuit in the wiring harness.

(2) Check for continuity to earth on terminals
A12, D1, D6 and also D3 and D10 on 1.8 liter
engines.

If there is no continuity check the earth connec-
tions at the right hand rear cylinder head bolts. If the
connections are clean and secure, repair the open
circuit in the wiring harness.

MEM-CAL UNIT
To Test - Code 51

If code 51 is displayed during the self diagnosis
test procedure, pr oceed as follows:

(1) Check that the Mem-Cal unit is fully inserted
in the control unit. (2) Erase the fault code memory and retest for
fault codes. (3) If code 51 is still displayed, renew the
Mem-Cal unit.
(4) Erase the fault code memory and retest for
fault codes. (5) If code 51 is still displayed, renew the control
unit.
To Remove and Install

The Mem-Cal unit is incorporated within the
control unit. Refer to the previous heading for the
removal and installation procedure.

FUEL PUMP AND EGI RELAYS
To Remove and Install
(1) Disconnect the negative battery terminals.
(2) Remove the fuse panel cover which is lo-
cated adjacent to the steering column under the
instrument cluster. (3) Remove the spare fuse holder from the fuse
panel and remove the releva nt relay from the connec-
tor. Installation is a reversal of the removal procedure.


View showing the location of the EGI and fuel pump
relays.
To Test Relays
NOTE: When testing the fuel pump relay
circuit ensure that th e EGI relay is service-
able and installed to the relay connector

(1) Remove the relevant relay as previously
described. (2) Using an ohmmeter, check for continuity
between terminals 1 and 2, and 3 and 5. Continuity should exist be tween terminals 1 and 2
but should not exist between terminals 3 and 5.

(3) Using suitable jumper leads, apply 12 volts
to terminal 1 and connect terminal 2 to a good earth
point. (4) Connect the ohmmeter between terminals 3
and 5. Continuity should exist. If continuity does not
exist, renew the relay.

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.

Fuel and Engine Management 113
(2) Disconnect the wiring connector from the
MAT sensor.

(3) Unscrew the sensor from the inlet manifold.
Installation is a reversal of the removal procedure

with attention to the following points:
(1) Apply Loctite 567 or a similar conductive
sealer to the threads of th e sensor. Tighten the sensor
to the specified torque. (2) Ensure that the wiring connector is clean and
tight.
OXYGEN SENSOR

To Test - Code 13
(1) Run the engine until the normal operating
temperature is obtained. (2) With the ignition switched Off, connect a
jumper lead between terminals A and B on the
diagnostic link connector.
(3) Start and run the engi ne at approximately
1 600-1 800 rpm for 2 minutes and note the ECM
warning lamp.
If the ECM warning lamp flashes at the rate of
twice per second, proceed to operation (5).

If the ECM warning lamp flashes at the rate of
once per second or slower, proceed as follows.

(4) Remove the jumper lead from the diagnostic
link connector and run th e engine above 2 000 rpm
for 2 minutes, noting the ECM warning lamp.

If the ECM warning lamp lights, stop the engine,
switch the ignition On and connect a jumper lead
between terminals A and B on the diagnostic link
connector. If code 13 is displayed proceed to opera-
tion (5).

If the ECM warning lamp does not light, 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.
(5) Switch the ignition Off and disconnect the
oxygen sensor wiring connector. Using a jumper lead
connect the oxygen sensor wiring connector to a
suitable engine earth. (6) Start and run the engi ne at approximately
1 600-1 800 rpm and note the ECM warning lamp.
The lamp may flash for a few seconds but should then
extinguish for at least 30 seconds.
If the ECM warning lamp functions as described,
proceed to operation (7).

If the ECM warning lamp does not function as
described proceed as follows:

(a) Check the wiring harness between the oxygen
sensor wiring connector and the control unit wiring
connector D7 for open circuits. Repair or renew the
wiring harness as necessary.

{b) Check the earth circuit between the control
unit wiring connect D6 and the right rear cylinder
head bolts. Repair or renew the wiring harness as
necessary.

(c) If no fault is found in (a) and (b) renew the
control unit and retest for fault codes.

(7) Check the wiring harness earth circuit be-
tween the control unit wiring connector D6 and the
right rear cylinder head bolts. Repair or renew the
wiring harness as necessary.

If no fault is found, thoroughly check the oxygen
sensor connector. If the conne ctor is not faulty, renew
the oxygen sensor.

To Test - Code 44
(1) Run the engine until normal operating tem-
perature is attained.
(2) With the ignition switched Off, connect a
jumper lead between terminals A and B on the
diagnostic link connector. (3) Start and run the engi ne at approximately
1 600-1 800 rpm for 2 minutes and note the ECM
warning lamp. If the ECM warning lamp is off more than on or
flashes at the rate of twice per second, proceed to
operation (4).

If the ECM warning lamp flashes evenly at the
rate of once per second 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) Switch the engine Off and disconnect the
oxygen sensor wiring connector.
(5) Start and run the engine at 1 600-1 800 rpm
for at least 30 seconds and note the ECM warning
lamp. If the ECM warning lamp flashes at the rate of
twice per second procee d to operation (6).

If the ECM warning lamp extinguishes for at least
30 seconds, check the wiring harness between the
oxygen sensor wiring connector and the control unit
wiring connector terminal D7 for shorts to earth.

Repair or renew the wiring harness as necessary.
If no fault can be found in the wiring harness, renew
the control unit.

Installed view of the oxygen sensor.

Fuel and Engine Management 115
Erase the fault codes and retest for fault codes as
follows:

(2) Start and run the engine until normal oper-
ating temperature is attained. (3) Drive the vehicle at a speed of at least 80
km/h and, with the throttle closed, allow the vehicle to
decelerate until the engine speed is below 1 500 rpm.
NOTE: After rectifying any fault it will be
necessary to retest for fault codes. To test for
Code 24 the vehicle must be driven as
previously described.

(4) Switch the engine Off and connect a jumper
lead between terminals A and B on the diagnostic link
connector. Switch the ignition On and note the fault
codes. If code 24 is displayed proceed as follows. (5) Check the operation of the speedometer and
the instrument cluster warning lamps. If the speed-
ometer only is not functioning, proceed to operation
(13).
If the speedometer and the instrument cluster
warning lamps are not functioning, a fault in the
instrument cluster wiring harness is indicated. Refer
the fault to an auto electrical workshop or a Nissan
dealer.

If the speedometer is functioning, proceed as
follows:

(6) Raise the front of the vehicle and support it
on chassis stands. (7) Place the transaxle in Neutral and switch the
ignition On. (8) With the aid of assistants, slowly spin the
front wheels by hand while backprobing the control
unit wiring connector terminal A10 with a digital
voltmeter to earth. The voltage should alternate from under 1 volt to
over 10 volts.

If the voltmeter readi ng is not as specified,
proceed to operation (9).

If the voltmeter reading is as specified, the vehicle
speed sensor is operating satisfactorily, indicating an
intermittent fault was the cause of the fault code.
Proceed as follows:

(a) Check for faulty wiri ng connections. Check
that all wiring connectors are clean and secure. (b) Check that all earth c onnections are secure.
(9) Remove the instrument cluster as described
in the Electrical System section. (10) With the ignition switched On, backprobe
the control unit wiring connector terminal A10 with a
voltmeter to earth. The voltage should be over 10
volts. If the voltage is less than specified, check the
wiring harness for shorts to earth between the black
and yellow wire terminal on the instrument cluster
wiring connector and the control unit connector
terminal A10. Repair or renew the wiring harness as
necessary. If no fault can be found, renew the control
unit.

(11) With the ignition switched On, backprobe
the black and yellow wire terminal on the instrument
cluster wiring connector with a voltmeter to earth.
The voltage should be over 10 volts.

If the voltage is less than specified, locate the open
circuit between the instrument cluster black and
yellow wire terminal and the control unit wiring
connector terminal A10. Repair or renew the wiring
harness as necessary.

(12) With a test lamp connected to 12 volts,
backprobe the black wire terminals on the instrument
cluster wiring connectors. The test lamp should light.

If the test lamp does not light locate the open
circuit between the black wire terminals and earth.
Repair or renew the wiring harness as necessary.

If the test lamp does light, renew the signal
divider circuit board which is located in the instru-
ment cluster.

(13) With the ignition switched On and the
engine not running, disconnect the vehicle speed
sensor wiring connector from the harness connector.
(14) With a test lamp connected to earth, probe
the yellow wire terminal on the harness wiring con-
nector. The test lamp should light. If the test lamp does not light, locate the open
circuit between the yellow wi re terminal and the Fuel
Pump fuse. Repair or renew the wiring harness as
necessary.

(15) With a test lamp connected to 12 volts,
probe the black wire terminal on the harness wiring
connector. The test lamp should light.

If the test lamp does not light, locate the open
circuit between the black wire terminal and earth.
Repair or renew the wiring harness as necessary.

(16) Using a voltmeter measure the voltage at the
red wire terminal on the harness wiring connector.

If the voltage is 5-9 volts proceed to operation
(19).

If the voltage is over 9 vol ts proceed to operation
(18).

Installed view of the vehicle speed sensor.