transmission MAZDA MIATA 1997 Factory Repair Manual

Fig. 6: Testing ABS Control Module (3 Of 3)
Courtesy of MAZDA MOTORS CORP.
HYDRAULIC UNIT
On-Vehicle Inspection
1. Ensure all diagnostic trouble codes have been cleared and battery is fully charged. See CLEARING
CODES under DIAGNOSIS & TESTING. Turn ignition on and check if ABS warning light goes out
after 2-4 seconds. If ABS warning light remains illuminated, ABS control module has detected a failure
and will not activate hydraulic unit. See DIAGNOSIS & TESTING
.
2. Turn ignition off. Ensure vehicle is on level surface. Raise and support vehicle. Place transmission in
Neutral. Release parking brake. Rotate wheels by hand and check for brake drag. Connect a jumper wire
between TBS terminal and GND terminal of data link connector. See Fig. 1
. Depress brake pedal and
have an assistant attempt to rotate right front wheel. Wheel should not rotate.
3. With brake pedal still depressed, turn ignition on. Brake should be momentarily released (about .5
second) and wheel should turn when pressure reduction operates. Check operation of remaining wheels
using same procedure beginning with left front, right rear, then left rear wheels.
4. If all wheels operate as specified, the following systems are operating properly.
Brake piping to hydraulic unit.
Braking system, including hydraulic unit.
Hydraulic unit electrical system (solenoid, pump motor, etc.)

1997 Mazda MX-5 Miata
ANTI-LOCK BRAKE SYSTEM 1997 BRAKES Mazda - Anti-Lock
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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
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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
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Sensor is a cable driven pulse generator that is part of speedometer. Pulse signals are sent to TCM.
TCM OUTPUT DEVICES
HOLD Indicator Light
Receives signal from TCM to indicate switch position.
Inhibitor Signal
When shift selector lever is moved from Park or Neutral to another gear, signal is sent from TCM to ECM to
regulate fuel injection volume for shift shock prevention.
Shift Solenoids & 3-2 Control Solenoid
The TCM controls transmission shifting by delivering an output signal to operate proper solenoid. 3-2 control
solenoid affects downshift timing. See SOLENOID OPERATION
table. Hydraulic pressure is retained when
solenoid is off and drained when solenoid is on. Solenoids are located on transmission valve body. See Fig. 1
.
SOLENOID OPERATION
TCC Solenoid Valve
Solenoid valve is ON/OFF type controlled by TCM. Solenoid regulates pilot pressure to applied to lock-up
control plug. Hydraulic pressure is retained when solenoid is on and drained when solenoid is off. Solenoid is
located on side of case. See Fig. 1
.
Shift Lever Position1-2 Shift Solenoid2-3 Shift Solenoid
3-4 Shift
Solenoid
"D" (Drive)
1st GearOnOnOn
2nd GearOffOnOn
3rd GearOffOffOn
4th GearOffOffOff
"2" (Second)
1st GearOnOnOn
2nd GearOffOnOn
"L" (Low)
1st GearOnOnOn
"R" (Reverse)OffOffOn
"N" or "P"OnOnOn

1997 Mazda MX-5 Miata
1997 AUTOMATIC TRANSMISSIONS NC4A-EL Electronic Controls
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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
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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
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Fig. 2: Locating Data Link Connector (DLC) Location
Courtesy of MAZDA MOTORS CORP.
DIAGNOSTIC TROUBLE CODE IDENTIFICATION
DTC No.(1) Probable Cause
P0705 Transmission Range Sensor Malfunction

1997 Mazda MX-5 Miata
1997 AUTOMATIC TRANSMISSIONS NC4A-EL Electronic Controls
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CLEARING CODES
To clear DTC stored in TCM, use scan tool. See scan tool instruction manual. Road test vehicle.
COMPONENT LOCATION
COMPONENT LOCATION
COMPONENT CONNECTOR IDENTIFICATION
P0706 Transmission Range Sensor Range/Performance
P0710 (2) TFT Sensor Malfunction
P0711 (2) TFT Sensor Range/Performance
P0715 Input/Turbine Speed Sensor
P0725 Engine Speed Input Circuit Malfunction
P0731 Incorrect 1st Gear Ratio
P0732 Incorrect 2nd Gear Ratio
P0733 Incorrect 3rd Gear Ratio
P0734 Incorrect 4th Gear Ratio
P0740 TCC System Malfunction
P0750 1-2 Shift Solenoid
P0755 2-3 Shift Solenoid
P0760 3-4 Shift Solenoid
P1720 Vehicle Speed Sensor
P1743 Lock-Up Solenoid Valve
P1765 3-2 Timing Control Solenoid Valve
P1790 Throttle Position Sensor
P1795 Idle Switch
(1)Check listed component for probable cause. Check wiring and connection of specified component.
(2)Transmission Fluid Temperature.
DescriptionLocation
Engine Control ModuleBehind Passenger Seat
Input/Turbine Speed SensorMounted To 4th Gear Case
Shift SolenoidsSee Fig. 1
TCC Lock-Up SolenoidSee Fig. 1
Transmission Control UnitAbove Fuse Box
3-2 Control ValveSee Fig. 1
TFT SensorMounted In-Line To Cooler Line
Vehicle Speed SensorMounted In Speedometer

1997 Mazda MX-5 Miata
1997 AUTOMATIC TRANSMISSIONS NC4A-EL Electronic Controls
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COMPONENT CONNECTOR IDENTIFICATION (1)
Fig. 3: Locating Transmission Component Connectors
ComponentSee Fig.
Engine Control Module (ECM)Fig. 5
Hold Switch(2)
Instrument Cluster(3)
Transmission Control Module (TCM)Fig. 4
Valve Body Solenoids(4)
(1)For connector location see Fig. 3 .
(2)See HOLD SWITCH under COMPONENT TESTING.
(3)See VEHICLE SPEED SENSOR (VSS) under COMPONENT TESTING.
(4)See SOLENOID VALVES under COMPONENT TESTING.

1997 Mazda MX-5 Miata
1997 AUTOMATIC TRANSMISSIONS NC4A-EL Electronic Controls
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Courtesy of MAZDA MOTORS CORP.
Fig. 4: Identifying TCM Component Connector Terminals

Courtesy of MAZDA MOTORS CORP.
Fig. 5: Identifying ECM Component Connector Terminals

Courtesy of MAZDA MOTORS CORP.
DIAGNOSTIC TESTS
DTC P0705: TRANSMISSION RANGE SWITCH CIRCUIT MALFUNCTION & DTC P0706:
TRANSMISSION RANGE SWITCH CIRCUIT RANGE/PERFORMANCE
Condition
No signal is received from range switch or more than 2 signals are received at one time. Possible causes for
either condition are:
Transmission range switch malfunction.
Damaged wiring or connectors between transmission range switch and TCM.
TCM malfunction.
Diagnosis & Repair Procedure
NOTE: For connector terminal identification, see COMPONENT CONNECTOR
IDENTIFICATION table under SELF-DIAGNOSTIC SYSTEM. For circuit or wire
color identification, see appropriate wiring diagram in WIRING DIAGRAMS
.

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