1991 ACURA NSX Service Repair Manual

— Defective gauge assemble, check for the A21
Speed Sensor Input Test

NOTE
:
Check the No. 2 (15 A) fuse in the under-dash


fuse box, before testing.
1. Disconnect the 3-P connector from the speed sensor.

View from

terminal side

SPEED SENSOR

3-P CONNECTOR

2. Check for continuity between the BLK terminal and the body ground.
There should be continuity. If there is no continuity, check for:
— An open in the BLk wire.
— Poor ground (G101) If there is continuity, go to step 3.
3. Check for vortage between the BLK/YEL terminal and the body ground with the ignition switch ON.
There should be battery voltage. If there is no voltage, check for an open in the
BLK/YEL wire. If there is battery voltage, go to step 4.
4. Check for voltage between the YEL/RED terminal and

bod
y
ground with the ignition switch ON.

There should be approximately 5 V.
If there is no voltage, check for:
terminal of the A connector (see page 23-121). If there are approximately 5 V, go to step 5.
5. If all continuity and voltage tests are normal, but the speedometer and the odo/trip meter do not operate,
replace the speed sensor.
Replacement

1. Disconnect the 3-P connector from the speed sensor.
2. Remove the mounting bolts and the speed sensor,
then take out the speed sensor assembly.

DRIVE LINK
3-P CONNECTOR

3. Install in the reverse order of removal. NOTE: Be careful not to lose the drive link, because
it is a tiny part.

BLK

YEL/RED

BLK/YEL
SPEED SENSOR
COVER

MOUNTING BOLTSProCarManuals.com

CAUTION:

All SRS electrical wiring harnesses are covered with
yellow outer Insulation. Before disconnecting the SRS wire harness, Install
the short connector on the airbag (see page STET). Replace the entire affected SRS harness assembly
if it has an open circuit or damaged wiring. After installation of the gauge assembly, recheck the
operation of the SRS indicator light.
Remove the dashboard lower cover, center panel and in-

strument panel. Disconnect the 8-connector (30-P) from

the gauge assembly. (See page 23-126)

Make the following input tests at the connector termi-

nals. If all tests prove OK, yet the indicator stilt fails to
work, replace the safety indicator.
A-CONNECTOR (Carries the SRS indicator signal)

SRS MAIN WIRE HARNESS
A-CONNECTOR

YEL

GRN/RED
View from terminal side

Safety Indicator
Indicator Input Test

B-CONNECTOR

RED/YEL

BLK/WHT
GRN/BLK
BLU

GRN/BLU
BLKProCarManuals.com

*: Terminal is floor wire harness side.No. Wire
Test condition
Test: desired result Possible cause (if result is not obtained)ProCarManuals.com

Safety Indicator

Troubleshooting

NOTE: The numbers in the table show the troubleshooting sequence.ProCarManuals.com

Shift Lever Position Indicator
CAUTION: All SRS electrical wiring harnesses are covered with
yellow outer insulation. Before disconnecting the SRS wire harness, install
the short connector on the airbag (see page STET) Replace the entire affected SRS harness assembly
if it has an open circuit or damaged wiring. After installation of the gauge assembly, recheck the
operation of the SRS indicator light.
GAUGE ASSEMBLY
Removal, page 23-126
Disassembly, pages 23-129
INTERLOCK SYSTEM

See page, 23-140
A/T CONTROL SYSTEM
See Automatic Transmission, section 14

SRS MAIN WIRE HARNESS

SHIFT LEVER POSITION

INDICATOR

Input Test, page 23-158

A/T CONTROL UNIT

See Automatic Transmission
section 14

SHIFT POSITION

CONSOLE SWITCH

Test, page 23-160
Replacement, page 23-161
Component Location IndexProCarManuals.com

Shift Lever Position Indicator
CAUTION: All SRS electrical wiring harnesses are covered with
yellow outer insulation. Before disconnecting the SRS wire harness, Install
the short connector on the airbus (see page 23-323). Raplace the entire affected SRS harness assembly
if it has an open circuit or damaged wiring. After installation of the gauge assembly, recheck the
operation of the SRS indicator light.
Remove the gauge assembly from the dashboard and dis-
connect the 30-P connector from the gauge assembly.
Make the following input tests at the connector termi-

nals. If all tests prove OK, yet the indicator still fails to
work, replace the main printed circuit panel, speedome-
ter, tachometer and odo/trip meter.
A-CONNECTOR (Carries the SRS indicator signal)

SRS MAIN WIRE HARNESS

A-CONNECTOR

30-P CONNECTOR

Indicator Input Test

YEL

BLK
RED/BLK

RED
LT GRN
GRN/YEL

LT GRN/WHT

YEL/BLU
GRY/WHT
GRN

LT BLU
YEL/BLK
BRN/BLK

View from wire sideProCarManuals.com

ProCarManuals.com

Integrated Control Unit
Input Test
CAUTION: All SRS electrical wiring harnesses are covered with
yellow outer insulation.Before disconnecting the SRS wire harness, install
the short connector on the airbag (see page 23-323). Replace the entire affected SRS harness assembly
if it has an open circuit or damaged wiring.
Remove the left side kick panel cover, and the dash re-
lay holder from the bracket, to disconnect the 16-P con-

nector from the integrated control unit.

Remove the integrated control unit from the dash fuse box.

Make the following input tests at the connector ter-

manals. If all tests prove OK, yet the system still falls

to work, replace the control unit.

NOTE: Several different wires have the same color. They
have been given a number suffix to distinguish them (for
example YEL and YEL are not the same).
SRS MAIN WIRE HARNESS
INTEGRATED
CONTROL UNIT
16-P CONNECTOR
UNDER-DASH FUSE BOX Not used

View from wire sideProCarManuals.com