Nissan Silvia. Manual — part 155

Main 12 Causes of Overheating

=NMEC0703

Engine

Step

Inspection item

Equipment

Standard

Reference page

OFF

1

I

Blocked radiator

I

Blocked condenser

I

Blocked radiator grille

I

Blocked bumper

I

Visual

No blocking

—

2

I

Coolant mixture

I

Coolant tester

50 - 50% coolant mixture See MA-9, “Engine Cool-

ant Mixture Ratio”.

3

I

Coolant level

I

Visual

Coolant up to MAX level
in reservoir tank and
radiator filler neck

See LC-15, “Changing
Engine Coolant”.

4

I

Radiator cap

I

Pressure tester

59 - 98 kPa
(0.59 - 0.98 bar, 0.6 - 1.0
kg/cm

2

, 9 - 14 psi) (Limit)

See LC-10, “System
Check”.

ON*

2

5

I

Coolant leaks

I

Visual

No leaks

See LC-10, “System
Check”.

ON*

2

6

I

Thermostat

I

Touch the upper and
lower radiator hoses

Both hoses should be
hot

See LC-13, “Thermostat”
and LC-14, “Radiator”.

ON*

1

7

I

Cooling fan

I

CONSULT-II

Operating

See “DTC P0208 OVER-
HEAT” (EC-120).

OFF

8

I

Combustion gas leak

I

Color checker chemi-
cal tester 4 Gas ana-
lyzer

Negative

—

ON*

3

9

I

Coolant temperature
gauge

I

Visual

Gauge less than 3/4
when driving

—

I

Coolant overflow to
reservoir tank

I

Visual

No overflow during driv-
ing and idling

See LC-15, “Changing
Engine Coolant”.

OFF*

4

10

I

Coolant return from
reservoir tank to radia-
tor

I

Visual

Should be initial level in
reservoir tank

See LC-16, “Refilling
Engine Coolant”.

OFF

11

I

Cylinder head

I

Straight gauge feeler
gauge

0.1 mm (0.004 in) Maxi-
mum distortion (warping)

See EM-43, “Inspection”,
“CYLINDER HEAD”.

12

I

Cylinder block and pis-
tons

I

Visual

No scuffing on cylinder
walls or piston

See EM-70, “Inspection”,
“CYLINDER BLOCK”.

*1: Turn the ignition switch ON.
*2: Engine running at 3,000 rpm for 10 minutes.
*3: Drive at 90 km/h (55 MPH) for 30 minutes and then let idle for 10 minutes.
*4: After 60 minutes of cool down time.
For more information, refer to LC-21, “OVERHEATING CAUSE ANALYSIS”.

SEF145X

Component Inspection

NMEC0704

COOLING FAN RELAYS-1 AND -2

NMEC0704S01

Check continuity between terminals 3 and 5.

Conditions

Continuity

12V direct current supply between terminals 1 and
2

Yes

No current supply

No

If NG, replace relay.

GI

MA

EM

LC

FE

CL

MT

AT

PD

AX

SU

BR

ST

RS

BT

HA

SC

EL

IDX

DTC 0208 OVERHEAT (COOLING SYSTEM)

Main 12 Causes of Overheating

EC-135

SEC445C

COOLING FAN MOTOR

NMEC0704S03

1.

Disconnect cooling fan motor harness connectors.

2.

Supply cooling fan motor terminals with battery voltage and
check operation.

Speed

Terminals

(+)

(−)

Cooling fan motor

Low

1

3

High

1, 4

2, 3

Cooling fan motor should operate.
If NG, replace cooling fan motor.

DTC 0208 OVERHEAT (COOLING SYSTEM)

Component Inspection (Cont’d)

EC-136

SEF598K

Component Description

NMEC0705

The knock sensor is attached to the cylinder block. It senses
engine knocking using a piezoelectric element. A knocking vibration
from the cylinder block is sensed as vibrational pressure. This
pressure is converted into a voltage signal and sent to the ECM.

ECM Terminals and Reference Value

NMEC0706

Specification data are reference values and are measured between each terminal and ground.

CAUTION:

Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM’s transistor. Use a ground other than ECM terminals, such as the ground.

TERMI-

NAL

NO.

WIRE

COLOR

ITEM

CONDITION

DATA (DC Voltage)

27

W

Knock sensor

[Engine is running]

I

Idle speed

Approximately 2.5V

On Board Diagnosis Logic

NMEC0707

DTC No.

Malfunction is detected when ...

Check Items (Possible Cause)

0304

I

An excessively low or high voltage from the knock sen-
sor is sent to ECM.

I

Harness or connectors
(The knock sensor circuit is open or shorted.)

I

Knock sensor

SEC447C

DTC Confirmation Procedure

NMEC0708

NOTE:
If “DTC Confirmation Procedure” has been previously conducted,
always turn ignition switch “OFF” and wait at least 5 seconds
before conducting the next test.
TESTING CONDITION:
Before performing the following procedure, confirm that bat-
tery voltage is more than 10V at idle.

With CONSULT-II

1)

Turn ignition switch “ON” and select “DATA MONITOR” mode
with CONSULT-II.

2)

Start engine and run it for at least 5 seconds at idle speed.

3)

If DTC is detected, go to “Diagnostic Procedure”, EC-139.

Without CONSULT-II

1)

Start engine and run it for at least 5 seconds at idle speed.

2)

Turn ignition switch “OFF”, wait at least 5 seconds and then
turn “ON”.

3)

Perform “Diagnostic Test Mode II (Self-diagnostic results)” with
ECM.

4)

If DTC is detected, go to “Diagnostic Procedure”, EC-139.

GI

MA

EM

LC

FE

CL

MT

AT

PD

AX

SU

BR

ST

RS

BT

HA

SC

EL

IDX

DTC 0304 KNOCK SENSOR (KS)

Component Description

EC-137

Wiring Diagram

NMEC0709

TEC804

DTC 0304 KNOCK SENSOR (KS)

Wiring Diagram

EC-138