fuse chart ACURA NSX 1991 Service User Guide

Idle Control System

Troubleshooting Flowchart
Air Conditioning Signal
This signals the PGM-FI ECU when there is a demand for cooling from the air conditioning system.

Inspection of Air Condition-

ing Signal.

Connect the ECU test harness

between the ECU and connector.

Disconnect "C" connector from
the engine wire harness only, not

the ECU (page 11-21).

Turn the ignition switch ON.
Measure voltage between C3 (+)

terminal and A26 (-) terminal.

Is there approx. 10 V?
Substitute a known-

good ECU and re-

check. If prescribed

voltage is now avail- able, replace the ori-

ginal ECU.
C3

A26

10 V

Turn the ignition switch OFF. Reconnect "C" connector to the
engine wire harness.
Turn the ignition switch ON.
Momentarily connect A15 ter-
minal to A26 terminal several
times.
Is there a clicking noise from the
A/C compressor clutch? Connect the RED/BLU terminal of

the 4P connector on the A/C

clutch relay to body ground. RED/BLU

A 15

Short
A26

View from UNDER-HOODFUSE/RELAY BOX side

Start the engine.
Is there a clicking noise from the
A/C compressor clutch?
See air conditioner in-

spection (section 22).

Repair open in RED/BLU wire be-

tween ECU (A15) and A/C clutch
relay.

Blower switch ON.
(To page 11-73)ProCarManuals.com

Idle Control System
Troubleshooting Flowchart

Starter Switch Signal

This signals the PGM-FI ECU when the engine is cranking.

Inspection of Starter Switch

Signal.

BATTERY

VOLTAGE?
C 11

A26

NOTE: Clutch pedal must be depress-
ed on M/T models.
Connect the ECU test harness
between the ECU and connector

(page 11-21).

Measure voltage between C11
(+) terminal and A26 (-) terminal
with the ignition switch in the
start position.

Is there battery voltage ?

Inspect No. 7 fuse.
Is No. 7 fuse OK ?

Replace fuse.

Repair open in BLK/WHT wire

between ECU (C11) and No. 7

fuse.

Starter switch signal is OK.ProCarManuals.com

Fuel Supply System
Main Relay (cont'd)

Troubleshooting Flowchart
Engine will not start.
Inspection of main relay.
Disconnect the main relay con-
nectors.
Measure the voltage between YEL/BLU terminal and body

ground.

Is there battery voltage? Replace ACG fuse.

Turn the ignition switch ON.

Measure the voltage between BLK/YEL terminal and body

ground.

Replace No. 2 fuse.
Is there battery voltage?
Measure the voltage between BLK/YEL terminal and body

ground.

Is there battery voltage? Replace IG COIL fuse. MAIN RELAY

BLK/

WHT

GRW

BLK

YEL/BLK

BLK/YEL

BLK/YEL
YEL/BLU
BLK

BLK/YEL

Turn the ignition switch START

position with the clutch pedal

depressed.
Measure the voltage between BLK/WHT terminal and body

ground.

Is there battery voltage? Replace No. 7 fuse.
(To page 11-105)ProCarManuals.com

Comes on and remains on while running:
1. Stop the engine.
2. Turn the ignition switch on and make sure that the anti-lock brake system indicator light comes on.
3. Restart the engine and check the anti-lock brake system indicator light.
There is no problem in the anti-lock brake system, if the anti-lock brake system indicator light goes off. Go to step 4, if the anti-lock brake system indicator light remains on.

4. Stop the engine.
5. Disconnect the service check connector from the connector cover located under the glove box.
Connect the two terminals of the service check connector with a jumper wire.
6. Turn the ignition switch on, but do not start the engine. 7. Record the blinking frequency of the anti-lock brake system indicator light.
The blinking frequency indicates the problem code.
CAUTION: Before starting the engine, disconnect the jumper wire from the service check connector, or else the
Check Engine light will stay on with the engine running.

Turn the ignition

switch on
PROBLEM CODE:

4– 2

Main Code: 4

Sub-Code: 2
PROBLEM

CODE: 1

Main Code: 1

Sub-Code: none
PROBLEM CODE

7–2

Main Code: 7

Sub-Code: 2

Indicator

light on

Indicator

light off
Connect the

jumper wire
2

Second

pause
1

Second

pause
5 second

pause

5 second

pause

1

Second

pause

1 Second

NOTE:
The control unit can indicate three problem codes (one, two or three problems). If the anti-lock brake system indicator light does not light, see Troubleshooting of Anti-lock Brake System
Indicator Light Circuit page 19-44.
If you miscount the blinking frequency, turn the ignition switch off, then turn on to blink the anti-lock brake
system indicator light again. After the repair is completed, disconnect the ALB 2,3 (No. 32) fuse for at least 3 seconds to erase the control

unit's memory. Then turn the ignition key on again and recheck.
The memory is erased if the connector is disconnected from the control unit or the control unit is removed from
the body. After recording the main and sub-code (if applicable), refer to the Symptom-to-System Chart.

ANTI-LOCK BRAKE SYSTEM INDICATOR LIGHT
SERVICE CHECK CONNECTOR

JUMPER WIREProCarManuals.com