1997 ACURA NSX heater

Radiator

Engine Coolant Refilling and Bleeding

CAUTION: When pouring engine coolant, be sure to

shut the relay box lid and not let coolant spill on the

electrical parts or the paint. If any coolant spills, rinse it

off immediately.

NOTE:

• Perform this maintenance when the engine is cool.

• Before replacing the coolant, turn the ignition ON,

slowly turn the climate control temperature knob to

90° and turn off the ignition. This will allow the

coolant in the heater to drain out with the rest of the

system.
1. Open the hood, the rear window and the engine

cover.

2. Remove the cover protecting the water pipes and

shift cables on the underside of the car.

3. Before removing the expansion tank cap, first

loosen the cap to lower pressure.

CAUTION: Do not remove the expansion tank cap

when engine is hot. The coolant is under pressure

and may blow out and scald you. Open the cap

slowly when the engine is cool.

4. Loosen the drain plug in the bottom of the radiator,

and drain the coolant.

5. Remove the two drain bolts from the water pipes,

and drain the coolant.

DRAIN BOLTS

15 N-m (1.5 kgf-m, 11 Ibf-ft)
DRAIN HOLE
DRAIN PLUG

WASHERS

Replace.ProCarManuals.com

21. Disconnect the engine wire harness connectors.

22. Remove the battery cable from the main fuse box.
24. Disconnect the two connectors from the emission

control box, then remove the control box.

• Do not disconnect the vacuum hoses.
Removal (cont'd)
Engine Removal/Installation

23. Disconnect the throttle body 6P connector, and

remove the ground cable and starter cable.
25. Remove the radiator hoses and heater hose.ProCarManuals.com

Engine Coolant Refilling and Bleeding

CAUTION: When pouring engine coolant, be sure to

shut the relay box lid and not let coolant spill on the

electrical parts or the paint. If any coolant spills, rinse it

off immediately.

NOTE:

• Perform this maintenance when the engine is cool.

• Before replacing the coolant, turn the ignition ON,

slowly turn the climate control temperature knob to

90° and turn off the ignition. This will allow the

coolant in the heater to drain out with the rest of the

system.
1. Open the hood, the rear window and the engine

cover.

2. Remove the cover protecting the water pipes and

shift cables on the underside of the car.

3. Before removing the expansion tank cap, first

loosen the cap to lower pressure.

CAUTION: Do not remove the expansion tank cap

when engine is hot. The coolant is under pressure

and may blow out and scald you. Open the cap

slowly when the engine is cool.

4. Loosen the drain plug in the bottom of the radiator,

and drain the coolant.

5. Remove the two drain bolts from the water pipes,

and drain the coolant.

WASHERS

Replace.

DRAIN BOLTS

15 N-m (1.5 kgf-m, 11 Ibf-ft)
DRAIN HOLE
DRAIN PLUGProCarManuals.com

10. Fill the expansion tank with engine coolant. As

coolant starts to run out in a steady stream without

bubbles, tighten the bleeders in sequence: thermo

cover bleed bolt, radiator bleed plug, heater pipe

bleed and water pipe bleed bolt.

11. After tightening all the bleeding bolts and plug, fill

the expansion tank with coolant up to the MAX line.

12. Loosen the thermo cover bleed bolt to remove any

remaining air.

13. When bleeding is completed, retighten the thermo

cover bleed bolt and fill the expansion tank up to

0.5
(0.53
US qt,
0.44
Imp qt) or 30 mm
(1.2
in)

over the MAX line.
14. Install the expansion tank cap, and turn it 60 degrees

(where it engages the first lock tab of filler neck).

1 5. Start the engine, and let it run until warmed up (until

the thermostat opens and the radiator cooling fan

runs).

16. Turn off the engine. Check the expansion tank and,

if needed, add engine coolant to bring it up to the

MAX line.

17. Tighten the expansion tank cap securely.

18. Reinstall the cover on the car's underside.ProCarManuals.com

Troubleshooting

Engine Control Module Terminal Arrangement

ECM CONNECTOR A (26P)

ECM CONNECTOR A (26P)
Wire side of female terminals

NOTE: Standard battery voltage is 12 V.

Terminal

number

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

20

21

22

23

24

25

26
Wire

color

BRN

RED

BLU

BLK/YEL

GRN/BLK

GRN

BLU

RED/BLU

GRY

LTGRN

PNK

BLK

YEL/BLK

YEL

BLK/RED

WHT/BLU

ORN

PNK/BLU

RED/YEL

GRN/RED

ORN/BLK

BRN

BLK

BRN/BLK
Terminal name

INJ1 (No. 1 FUEL INJECTOR)

INJ2 (No. 2 FUEL INJECTOR)

INJ3 (No. 3 FUEL INJECTOR)

VSV (EVAP CONTROL CANIS-

TER VENT SHUT VALVE)

FLR1 (FUEL PUMP RELAY)

ESOL (EGR CONTROL

SOLENOID VALVE)

MIL (MALFUNCTION

INDICATOR LAMP)

ACC (A/C CLUTCH RELAY)

FS02SHTC (FRONT SEC-

ONDARY HEATED OXYGEN

SENSOR HEATER CONTROL)

RS02SHTC (REAR SEC-

ONDARY HEATED OXYGEN

SENSOR HEATER CONTROL)

IGN COIL1 (No. 1 IGNITION

COIL part of IGNITION

CONTROL MODULE)

PG1 (POWER GROUND)

IGP1 (POWER SOURCE)

INJ4 (No. 4 FUEL INJECTOR)

INJ5 (No. 5 FUEL INJECTOR)

INJ6 (No. 6 FUEL INJECTOR)

2WBS (EVAP BYPASS

SOLENOID VALVE)

IABCS (IAB CONTROL

SOLENOID VALVE)

PCS (EVAP PURGE CONTROL

SOLENOID VALVE)

FP02SHTC (FRONT PRIMARY

HEATED OXYGEN SENSOR

HEATER CONTROL)

RP02SHTC (REAR PRIMARY

HEATED OXYGEN SENSOR

HEATER CONTROL)

IGN COIL2 (No. 2 IGNITION

COIL part of IGNITION

CONTROL MODULE)

PG2 (POWER GROUND)

LG1 (LOGIC GROUND)
Description

Drives No. 1 fuel injector

Drives No. 2 fuel injector

Drives No. 3 fuel injector

Drives EVAP control canister vent

shut valve

Drives fuel pump relay

Drives EGR control solenoid

valve

Drives MIL

Drives A/C clutch relay

Drives front secondary heated

oxygen sensor heater

Drives rear secondary heated

oxygen sensor heater

Sends ignition pulse

Ground for the ECM power circuit

Power source for the ECM control

circuit

Drives No. 4 fuel injector

Drives No. 5 fuel injector

Drives No. 6 fuel injector

Drives EVAP bypass solenoid

valve

Drives IAB control solenoid valve

Drives EVAP purge control

solenoid valve

Drives front primary heated

oxygen sensor heater

Drives rear primary heated

oxygen sensor heater

Sends ignition pulse

Ground for the ECM power circuit

Ground for the ECM control

circuit
Signal

With engine running: pulses

With ignition switch ON (II):

battery voltage

0 V for two seconds after turning ignition

switch ON (II), then battery voltage

With EGR operating during driving with

fully warmed up engine: duty controlled

With EGR not operating: battery voltage

With MIL turned ON: 0V

With MIL turned OFF: battery voltage

With compressor ON: 0 V

With compressor OFF: battery voltage

With ignition switch ON (II): battery

voltage

With fully warmed up engine running: 0 V

With ignition switch ON: battery voltage

With fully warmed up engine running:

pulses

With ignition switch ON (II): 0 V

With engine running: pulses

Less than 1.0 V at all times

With ignition switch ON (II): battery voltage

With ignition switch OFF: 0 V

With engine running: pulses

With ignition switch ON (II): battery

voltage

With engine speed below 4,800 rpm:

battery voltage

With engine speed above 4,800 rpm: 0 V

With engine running, engine coolant

below 153°F (67°C): battery voltage

With engine running, engine coolant

above 153°F (67°C): 0 V

With ignition switch ON (II): battery

voltage

With fully warmed up engine running: 0 V

With ignition switch ON (II): battery

voltage

With fully warmed up engine running: 0 V

With ignition switch ON (II): 0 V

With engine running: pulses

Less than 1.0 V at all times

Less than 1.0 V at all timesProCarManuals.com

Carpet

Replacement (cont'd)

5. Pull up the retainers, then remove the floor carpets.

6. Remove the console carpets.

FOOTREST
RETAINERS

FOOTREST MOUNTING

BOLTS

SEAT HARNESSES

7. Installation is the reverse of the removal procedure.

NOTE:

• Take care not to damage, wrinkle or twist the carpets.

• Make sure the air vents are connected, into the heater unit and air duct.

• Make sure the seat harnesses are routed correctly.
CONSOLE

CARPETS

RETAINERS
FLOOR CARPETS
SRS UNITProCarManuals.com

MODE CONTRO L MOTO R
Replacement , pag e 22-5 7
Test , pag e 22-5 8
EVAPORATO RTEMPERATUR ESENSORRemoval , pag e 22-6 5
Test , pag e 22-6 5 SUNLIGH
T SENSO R
Removal , pag e 22-6 3
Test , pag e 22-6 3
CLIMAT E CONTRO L UNI T
Replacement , pag e 22-5 4
Adjustment , pag e 22-5 5COMPRESSO R (NIPPONDENSO )
Compresse s th e refrigeran t an d
the n force s i t throug h th e condenser .
"DEF " DOO R
Adjustment , pag e 22-7 7"HEAT " DOO RAdjustment , pag e 22-7 7
BLOWE R UNI T
Replacement , pag e 22-6 7
Overhaul , pag e 22-6 8
RECEIVER/DRYE RServes a s a reservoi r whic h filter s an dremove s moistur e fro m th e refrigerant .
IN-CAR TEMPERATUR E SENSO R
Removal , pag e 22-6 1
Test , pag e 22-6 1
HEATER-EVAPORATO R
UNITReplacement , pag e 22-7 4
Overhaul , pag e 22-7 6
OUTSID E AI R TEMPERATUR E SENSO R
Removal , pag e 22-6 2
Test, pag e 22-6 2DUAL CONDENSE RDissipates th e hea t whic h wa sabsorbe d b y th e refrigerant .
Replacement , pag e 22-7 9
Overhaul , pag e 22-8 0
HEATE R COR E
TEMPERATUR E SENSO R
Removal , pag e 22-6 4
Test, pag e 22-6 4
AIR MI X CONTRO L
MOTO R
Replacement , pag e 22-5 6
Test , pag e 22-5 7
RECIRCULATIO
N
CONTRO L MOTO R
Replacement , pag e 22-5 9
Test , pag e 22-5 9 HEATE
R VALV E CABL E
Adjustment , pag e 22-58 , 22-7 5
VENT DOO R CONTRO L
MOTO R
Replacement , pag e 22-6 0Test, pag e 22-6 0
A/C TRIPL EPRESSUR E SWITC H
ProCarManuals.com

Heater-Evaporator Door Position

(MAX COOL)

U.S.A model

VENT DOOR

DEFROSTER

DOOR

HEAT

DOOR

AIR MIX DOOR

HEATER CORE
A/C EVAPORATOR

COREProCarManuals.com