1991 ACURA NSX turn signal bulb

Engine Control Module (ECM)

NOTE: If this symptom is intermittent, check for a loose No. 5 BACK-UP LIGHTS, ALTERNATOR,

TURN SIGNALS (15 A) fuse in the under-dash fuse/relay box, a poor connection at ECM terminal

A7, or an intermittent open in the BLU wire between the ECM (A7) and the gauge assembly.

Is the low oil pressure light on?

Try to start the engine.

Does the engine start?

Check for an open in the wire or

bulb:

1. Turn the ignition switch OFF.

2. Connect the ECM connector ter-

minal A7 to body ground with a

jumper wire.

3. Turn the ignition switch ON (II).

Is the MIL on?

Substitute a known-good ECM,

and recheck. If symptom/indica-

tion goes away, replace the origi-

nal
ECM.
— Repair short in the wire

between No. 5 BACK-UP

LIGHTS, ALTERNATOR, TURN

SIGNALS (15 A) fuse and

gauge assembly.

— Replace No. 5 BACK-UP

LIGHTS, ALTERNATOR, TURN

SIGNALS (15 A) fuse.

ECM CONNECTOR A (26P)

Check for an open in the wires

(PG line):

1. Turn the ignition switch ON (II).

2. Measure voltage between

body ground and ECM connec-

tor terminals A12 and A25 indi-

vidually.
WIRE SIDE OF FEMALE TERMINALS

Is there less than 1.0 V?
Repair open in the wire(s)

between ECM and G101 (located

at intake manifold) that had

more than 1.0V.

— Repair open in the wires

between ECM (A7) and gauge

assembly.

— Replace the MIL bulb.
WIRE SIDE OF FEMALE TERMINALS
ECM CONNECTOR A (26P)
Substitute a known-good ECM

and recheck. If symptom/indica-

tion goes away, replace the origi-

nal
ECM.
Turn the ignition switch ON (II).
The Malfunction Indicator Lamp

(MIL) never comes on (even for

two seconds) after ignition is

turned ON (II).ProCarManuals.com

Gauge Assembly

Bulb Locations

GAUGE LIGHTS (1.4W x 2)

SRS INDICATOR LIGHT (1.4 W)

RIGHT TURN SIGNAL INDICATOR LIGHT (1.4 W)

EPS INDICATOR LIGHT (1.4 W)

BRAKE SYSTEM LIGHT (1.4 W)

SEAT BELT REMINDER LIGHT (1.4 W)

TCS INDICATOR

LIGHT (1.96 W)

LOW FUEL INDICATOR

LIGHT (1.4 W)

GAUGE LIGHT

(1.4
W)
HIGH BEAM INDICATOR LIGHT (1.4 W)

LEFT TURN SIGNAL INDICATOR LIGHT (1.4 W)

ABS

INDICATOR LIGHT (1.4 W)

CHARGING SYSTEM LIGHT (1.4 W)

MALFUNCTION

INDICATOR

LAMP (MIL)

(1.4W)

LOW OIL PRESSURE

INDICATOR

LIGHT (1.4 W)

GAUGE LIGHT

(1.4
W)

GAUGE LIGHT

(3.0
W)
GAUGE LIGHT

(3.0
W)
GAUGE LIGHT

(3.0
W)
CRUISE INDICATOR LIGHT

(1.96
W)ProCarManuals.com

5. Disconnect the 18-P and 10-P connectors.

CAUTION: Be careful not to damage the SRS wire

harness.

6. Remove the six screws, then remove the headlight-

turn signal switch assembly.

HEADLIGHT SWITCH

10-P CONNECTOR

18-P CONNECTOR

TURN SIGNAL SWITCH

7. If necessary, remove the turn signal cancel unit and

cancel switch.

TURN SIGNAL

CANCEL UNIT
TURN SIGNAL

CANCEL SWITCH
8. If necessary, remove the headlight switch bulb.

HEADLIGHT SWITCH

BULB (0.91 W)ProCarManuals.com

Taillights

Replacement

1. Open the trunk lid, and remove the rear trim panel.

2. Disconnect the 8-P connector and 2-P connector

from the taillight assembly.

3. Disconnect the 2-P connector from the trunk key

cylinder switch.

8-P CONNECTOR

2-P CONNECTOR

TRUNK KEY CYLINDER

CONNECTOR

REAR TRIM PANEL

4. Remove the four mounting nuts and rear panel, then

remove the ten mounting nuts and the taillight as-

sembly.

NEW GASKET

REAR PANEL

TAILLIGHT ASSEMBLY

5. Inspect the gasket; if it is distorted or stays com-

pressed, replace it.

6. After installing, run water over the lights to make

sure they don't leak.
Bulb Replacement

1. Open the trunk lid, and remove the rear trim panel.

2. Turn each socket 45° counterclockwise to remove

them from the taillight housing.

SOCKET

TURN SIGNAL LIGHT BULB (45CP)

and BRAKE LIGHT/TAILLIGHT BULBS (32CP/2CP)

TAILLIGHT BULB (2CP)

BACK-UP LIGHT BULB (32CP)

3. Remove the bulbs from the sockets.ProCarManuals.com

3. Fuel Cut-off Control

During deceleration with the throttle valve closed, current to the fuel injectors is cut off to improve fuel economy

at speeds over 1,500 rpm.

Fuel cut-off action also takes place when engine speed exceeds, 8,300 rpm, regardless of the position of the

throttle valve, to protect the engine from over-revving.

4. A/C Compressor Clutch Relay

When the ECM receives a demand for cooling from the air conditioning system, it delays the compressor from being

energized, and enriches the mixture to assure smooth translation to the A/C mode.

5. Evaporative Emission (EVAP) Purge Control Solenoid Valve

When the engine coolant temperature is below 1 58 °F (70°C) the ECM supplies a ground to the EVAP purge control

solenoid valve which cuts vacuum to the EVAP purge control diaphragm valve.

6. Intake Air Bypass (IAB) Control Solenoid Valve

When the engine speed is below 4,800 rpm, the IAB control solenoid valve is activated by a signal from the ECM.

Intake air then flows through the smaller chamber, and hight torque is delivered. To increase air flow at engine speeds

higher than 4,800 rpm, the solenoid valve is deactivated by the ECM, and the intake air flows through the larger

chamber.

7. Exhaust Gas Recirculation (EGR) Control Solenoid Valve

When the EGR is required for control of oxides of nitrogen (NOx) emissions, the ECM supplies ground to the EGR

control solenoid valve which supplies regulated vacuum to the EGR valve.

ECM fail-safe/back-up Functions

1. Fail-Safe Function

When an abnormality occurs in a signal from a sensor, the ECM ignores that signal and assumes a pre-programmed

valve for that sensor that allows the engine to continue to run.

2. Back-up Function

When an abnormality occurs in the ECM itself, the fuel injectors are controlled by a back-up circuit independent of

the system in order to permit minimal driving.

3. Self-diagnosis Function [Malfunction Indicator Lamp (MIL)]

When an abnormality occurs in a signal from a sensor, the ECM lights the MIL and stores the diagnostic trouble code

in erasable memory. When the ignition is initially turned in, the ECM supplies ground for the MIL for two seconds

to check the MIL bulb condition.ProCarManuals.com

Gauge Assembly

Bulb Locations

SRS INDICATOR LIGHT (1.4W)

EPS INDICATOR LIGHT (1.4 W)

RIGHT TURN SIGNAL INDICATOR LIGHT (1.4 W)

BRAKE SYSTEM LIGHT (1.4W)

SEAT BELT REMINDER LIGHT (1.4W)

TCS-OFF INDICATOR

LIGHT (1.96 W)

LOW FUEL INDICATOR

LIGHT (1.4W)

GAUGE LIGHT

(1.4W)

GAUGE LIGHT

(3.0W)
CRUISE LIGHT

(1.96W)

GAUGE LIGHT

(3.0W)
TCS ACTIVATION

INDICATOR LIGHT

(1.96
W)

GAUGE LIGHT

(3.0W)
GAUGE LIGHT

(1.4W)
LOW OIL PRESSURE

INDICATOR

,LIGHT(1.4W)
MALFUNCTION

INDICATOR

LAMP (MIL)

(1.4W)
CHARGING SYSTEM LIGHT (1.4 W)
ABS

INDICATOR LIGHT (1.4 W)
LEFT TURN SIGNAL INDICATOR LIGHT (1.4 W)
TCS INDICATOR LIGHT (1.4W)
HIGH BEAM INDICATOR LIGHT (1.4W)
GAUGE LIGHTS (1.4W x 2)ProCarManuals.com

5. Remove the four screws from the headlight switch.
HEADLIGHT SWITCH 10-P CONNECTOR
16-P CONNECTOR
6. Disconnect the 10-P connector from the turn signal cancel unit, then remove the headlight switch and
turn signal switch.
7. Separate the headlight switch from the turn signal switch.
8. If necessary, remove the turn signal cancel unit and cancel switch.
TURN SIGNAL CANCEL UNIT TURN SIGNAL
CANCEL SWITCH

HOUSING

BULB (0.91 W)
4. Remove the bulb from the switch by turning it 45°. 3. Slide the headlight switch out of the housing as
shown.
HEADLIGHT SWITCH
1. Remove the headlight switch (see previous page).
2. Remove the two screws. Headlight Switch Light Bulb

ReplacementProCarManuals.com

5. Remove the four screws from the headlight switch.
HEADLIGHT SWITCH 10-P CONNECTOR
16-P CONNECTOR
6. Disconnect the 10-P connector from the turn signal cancel unit, then remove the headlight switch and
turn signal switch.
7. Separate the headlight switch from the turn signal switch.
8. If necessary, remove the turn signal cancel unit and cancel switch.
TURN SIGNAL CANCEL UNIT TURN SIGNAL
CANCEL SWITCH

HOUSING

BULB (0.91 W)
4. Remove the bulb from the switch by turning it 45°. 3. Slide the headlight switch out of the housing as
shown.
HEADLIGHT SWITCH
1. Remove the headlight switch (see previous page).
2. Remove the two screws. Headlight Switch Light Bulb

ReplacementProCarManuals.com