1997 MAZDA MX-5 instrument panel

Fig. 2: Locating Clockspring Alignment Marks
Courtesy of MAZDA MOTORS CORP.
DISABLING & ACTIVATING AIR BAG SYSTEM
DISABLING SYSTEM
Disconnect and shield negative battery cable. Wait at least one minute for back-up power supply to be depleted.
Remove cover panel below left side of instrument panel. Disconnect clockspring connectors for driver-side air
bag. See Fig. 3
. Remove glove compartment. Disconnect passenger-side air bag module connectors. See Fig.
4 .
WARNING:After disabling the air bag system, wait at least one minute before
servicing. Air bag system voltage is maintained for more than minute
after system is disabled. Failure to wait at least minute may cause
accidental air bag deployment and possible personal injury.

1997 Mazda MX-5 Miata
AIR BAG RESTRAINT SYSTEM 1997 ACCESSORIES/SAFETY EQUIPMENT Mazda - Air Bag Restraint System
Microsoft
Sunday, July 05, 2009 1:40:47 PMPage 4 © 2005 Mitchell Repair Information Company, LLC.

1. Disable air bag system. See DISABLING & ACTIVATING AIR BAG SYSTEM . Remove meter
hood. Ensure instrument cluster 12 pin connector is securely connected and that terminal No. 1 E is not
damaged. Check continuity between terminal No. 1E of 12 pin cluster connector and terminal No. 2K of
print plate of instrument cluster. If there is continuity, go to next step. If there is no continuity, replace
print plate and then go to next step.
2. Disable air bag system. See DISABLING & ACTIVATING AIR BAG SYSTEM
. Check if terminal
No. Q of 21 pin SAS unit connector is securely connected and is not damaged. If ok, go to next step. If
terminal Q is not securely connected or is damaged, replace air bag harness, then go to next step.
3. Disconnect 21 pin SAS unit connector and 12 pin instrument cluster connector. Check continuity between
terminal No. Q of SAS unit connector and terminal No. 1 E of instrument cluster connector. If there is
continuity, replace SAS unit and then go to next step. See SAS UNIT
under REMOVAL &
INSTALLATION. If there is no continuity, go to next step.
4. Activate air bag system. See DISABLING & ACTIVATING AIR BAG SYSTEM
. Check AIR BAG
warning light for proper system function. See SYSTEM OPERATION CHECK
.
WARNING LIGHT DOES NOT COME ON
Disable air bag system. See DISABLING & ACTIVATING AIR BAG SYSTEM
. Remove meter hood.
Ensure instrument cluster 12 pin connector is securely connected and that terminal No. 1 E is not damaged.
Check continuity between terminal No. 1E of 12 pin cluster connector and terminal No. 2K of print plate of
instrument cluster. If there is continuity, go to next step. If there is no continuity, replace print plate and then go
to next step.
WARNING LIGHT REMAINS ON
1. Measure battery voltage. If voltage is more than 9 volts, go to next step. If voltage is not more than 9
volts, check charging system.
2. Disable air bag system. See DISABLING & ACTIVATING AIR BAG SYSTEM
. Remove dashboard.
Remove heater unit. Check if SAS unit connector is securely connected. Check short bar between SAS
unit terminal No. Q and terminal No. S. If short bar is bent, replace wiring harness and then go to next
step. If short bar is OK, go to next step.
3. Check short bar hook on SAS unit. If hook is OK, go to next step. If hook is damaged, replace SAS unit.
See SAS UNIT
under REMOVAL & INSTALLATION.
4. Disconnect SAS unit 21 pin connector and instrument panel 12 pin connector. Carefully insert an
insulation material between terminal No. Q and terminal No. S of SAS unit so short bar cannot move. NOTE: For connector terminal identification, see WIRING DIAGRAM
.
NOTE: For connector terminal identification, see WIRING DIAGRAM
.
NOTE: For connector terminal identification, see WIRING DIAGRAM
.
NOTE: Use care not to damage short bar when inserting insulation material.

1997 Mazda MX-5 Miata
AIR BAG RESTRAINT SYSTEM 1997 ACCESSORIES/SAFETY EQUIPMENT Mazda - Air Bag Restraint System
Microsoft
Sunday, July 05, 2009 1:40:48 PMPage 16 © 2005 Mitchell Repair Information Company, LLC.

1997 AUTOMATIC TRANSMISSIONS
NC4A-EL Electronic Controls
APPLICATION
TRANSMISSION APPLICATION
DESCRIPTION
The NC4A-EL series is a 4-speed electronically controlled automatic transmission. Five solenoids attached to
valve body control shift changes. Solenoids are controlled by the Transmission Control Module (TCM).
The TCM receives information from various input devices. The TCM uses this information to control following
solenoids:
Shift solenoids for transmission shifting.
Torque Converter Clutch (TCC) solenoid for torque converter clutch lock-up.
3-2 control solenoid for downshift timing control.
A HOLD switch is mounted on the shift lever. HOLD function may be activated in "D", "S" or "L" gears by
pressing HOLD button. In "L" and "S" positions, vehicle is held in selected gear and no upshift or downshift
takes place. This function is used for driving up steep inclines or for engine braking assistance when descending
steep grades. If activated in "D" position a 1-2 and 2-3 upshift is permitted when starting from a stop, but after
the 2-3 upshift the vehicle is locked in "D" until it comes to a complete stop. The 1-2 and 2-3 upshift pattern is
changed to a "short shift" specification. This function is used for starting off or driving on slippery surfaces.
Pushin
g HOLD button again deactivates system.
VehicleTransmission Model
MiataNC4A-EL
CAUTION: Vehicle is equipped with Supplemental Restraint System (SRS). When
servicing vehicle, use care to avoid accidental air bag deployment. SRS-
related components are located in steering column, center console and
instrument panel. DO NOT use electrical test equipment on these circuits.
If necessary, deactivate SRS before servicing components. See AIR BAG
DEACTIVATION PROCEDURES article in GENERAL INFORMATION.
CAUTION: Disconnecting battery on models equipped with anti-theft radio require
canceling of anti-theft operation. See appropriate AUTOMATIC
TRANSMISSION SERVICING article in TRANSMISSION SERVICING. Refer
to vehicle owner's manual to identify radio type.
NOTE: Torque Converter Clutch (TCC) solenoid is also known as lock-up solenoid,
TCC lock-up or 4th gear solenoid.

1997 Mazda MX-5 Miata
1997 AUTOMATIC TRANSMISSIONS NC4A-EL Electronic Controls

1997 Mazda MX-5 Miata
1997 AUTOMATIC TRANSMISSIONS NC4A-EL Electronic Controls
Microsoft
Sunday, July 05, 2009 1:35:03 PMPage 1 © 2005 Mitchell Repair Information Company, LLC.
Microsoft
Sunday, July 05, 2009 1:35:38 PMPage 1 © 2005 Mitchell Repair Information Company, LLC.

OPERATION
TCM
TCM receives information from various input devices and uses this information to control solenoids on
transmission valve body for transmission shifting and torque converter clutch engagement.
TCM automatically switches from NORMAL mode to POWER mode corresponding to driving condition in
"D" range. Upshifts and downshifts are performed at a higher speed in POWER mode than in NORMAL mode.
TCM contains a self-diagnostic system, which will store Diagnostic Trouble Codes (DTC) if a failure or
problem exists in electronic control system. DTC can be retrieved to determine problem area. See SELF-
DIAGNOSTIC SYSTEM . TCM is located under left side of instrument panel, above fuse block.
TCM INPUT DEVICES & SIGNALS
4th Gear Inhibit Signal
Signal is input to TCM when cruise control is on. Signal detects when difference between target speed and
actual speed exceeds specification.
HOLD Switch
HOLD switch delivers input to TCM to indicate gears preferred by operator. Switch is located on shift lever
handle. HOLD switch is canceled when ignition switch is turned off.
Input/Turbine Speed Sensor
Sensor is a magnetic pick-up type pulse generator that monitors input shaft speed. AC waveform is input to
TCM by output speed sensor. Sensor is located on front of transmission, back of converter housing.
Throttle Position (TP) Sensor
TP sensor delivers an input signal to TCM indicating throttle valve position (opening). TP sensor is located on
side of throttle body.
Transmission Range Switch
Transmission range switch delivers an input signal to TCM indicating shift lever position. Switch is located on
side of transmission.
Transmission Fluid Temperature (TFT) Sensor
TFT sensor is threaded into cooler line banjo mounting on side of transmission case. Sensor sends signal to
TCM indicating fluid temperature.
Vehicle Speed Sensor

1997 Mazda MX-5 Miata
1997 AUTOMATIC TRANSMISSIONS NC4A-EL Electronic Controls
Microsoft
Sunday, July 05, 2009 1:35:03 PMPage 2 © 2005 Mitchell Repair Information Company, LLC.

Fig. 1: Locating Solenoid Valves
Courtesy of MAZDA MOTORS CORP.
SELF-DIAGNOSTIC SYSTEM
SYSTEM DIAGNOSIS
TCM monitors transmission operation and contains a self-diagnostic system which stores a Diagnostic Trouble
Code (DTC) if an electronic control system failure or component malfunction exists. If a problem exists in any
of the solenoids or speed sensors and DTC is set, TCM will deliver a signal to blink the HOLD indicator light
on instrument panel to warn the driver. DTC may be set if a failure exists and can be retrieved for transmission
diagnosis.
RETRIEVING TROUBLE CODES
NOTE: Before testing transmission, ensure fluid level is correct. Ensure engine starts
with shift lever in Park and Neutral to ensure proper adjustment of transmission
range switch. Transmission Control Module (TCM) must first be checked for
stored codes. See RETRIEVING TROUBLE CODES
.
NOTE: Before retrieving DTC, ensure proper battery voltage exists for self-diagnostic
system operation. If any DTC are present other than those listed below, see

1997 Mazda MX-5 Miata
1997 AUTOMATIC TRANSMISSIONS NC4A-EL Electronic Controls
Microsoft
Sunday, July 05, 2009 1:35:03 PMPage 4 © 2005 Mitchell Repair Information Company, LLC.

Using Scan Tool
Ensure ignition is in OFF position. Connect scan tool to Data Link Connector (DLC) located under left side of
instrument panel, near center console. Turn ignition switch to ON position. Check for stored DTC. See
DIAGNOSTIC TROUBLE CODE IDENTIFICATION
table. For trouble shooting of codes, see
DIAGNOSTIC TESTS
. appropriate SELF-DIAGNOSTIC SYSTEM article in ENGINE PERFORMANCE.

1997 Mazda MX-5 Miata
1997 AUTOMATIC TRANSMISSIONS NC4A-EL Electronic Controls
Microsoft
Sunday, July 05, 2009 1:35:03 PMPage 5 © 2005 Mitchell Repair Information Company, LLC.

Fig. 3: Main Fuse Block Legend
Courtesy of MAZDA MOTORS CORP.
FUSE BLOCK
Fuse block is located under driver's side of instrument panel. See Fig. 4
.
Fig. 4: Locating Fuse Block

Courtesy of MAZDA MOTORS CORP.

1997 Mazda MX-5 Miata
1997 ELECTRICAL Fuses & Circuit Breakers - MX-5 Miata
Microsoft
Sunday, July 05, 2009 1:54:39 PMPage 3 © 2005 Mitchell Repair Information Company, LLC.

HEATER SYSTEM
1997 Heater System
DESCRIPTION & OPERATION
Heater case, mounted under center of instrument panel, contains airflow mode doors and air-mix (temperature
blend) doors. See Fig. 1
. Blower case, mounted under right side of instrument panel, contains blower motor,
blower resistor and fresh/recirculated air door. All doors are controlled manually from control panel by cable.
Blower resistors, located on bottom of blower case, determine blower speed. WARNING:To avoid injury from accidental air bag deployment, read and follow all
SERVICE PRECAUTIONS and DISABLING & ACTIVATING AIR BAG
SYSTEM procedures in AIR BAG RESTRAINT SYSTEM article in the
ACCESSORIES/SAFETY EQUIPMENT section.
CAUTION: When battery is disconnected, radio will go into anti-theft protection
mode. Obtain radio anti-theft protection code from owner prior to
servicing vehicle.

1997 Mazda MX-5 Miata
HEATER SYSTEM 1997 Heater System

1997 Mazda MX-5 Miata
HEATER SYSTEM 1997 Heater System
Microsoft
Sunday, July 05, 2009 1:46:56 PMPage 1 © 2005 Mitchell Repair Information Company, LLC.
Microsoft
Sunday, July 05, 2009 1:47:02 PMPage 1 © 2005 Mitchell Repair Information Company, LLC.