1997 MAZDA MX-5 clutch

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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Condition
TCM outputs solenoid pattern of 1st gear when gear ratio is other than 1st gear. Possible causes are:
Low ATF level.
Low line pressure.
Control valve stuck.
Solenoid valve malfunction.
TCM malfunction.
Diagnosis & Repair Procedure
1. Ensure ATF level and condition is okay. Check line pressure and stall speed. See LINE PRESSURE
TEST and STALL SPEED under TESTING in MAZDA NC4A-EL OVERHAUL article. Repair any
components as necessary. If malfunction is not present, go to next step.
2. Inspect 1-2, 2-3 and 3-4 shift solenoid valves. See SOLENOID VALVES
under COMPONENT
TESTING. Repair as needed. If solenoid valves are okay, go to next step.
3. Inspect valve body. Ensure all valves operate smoothly. Repair as needed. If valve body is okay, go to
next step.
4. Clear DTC and retest. See CLEARING CODES
. If code P0731 is still present, replace TCM. If code is
no longer present and symptom still exists, problem may be caused by intermittent clutch slippage.
Further investigation may be required. See MAZDA NC4A-EL OVERHAUL article.
DTC P0732: INCORRECT 2ND GEAR RATIO
Condition
TCM outputs solenoid pattern of 2nd gear when gear ratio is other than 2nd gear. Possible causes are:
Low ATF level.
Direct clutch slippage.
One-way clutch slippage.
Faulty band servo.
Low line pressure.
Control valve stuck.
Solenoid valve malfunction.
TCM malfunction.
Diagnosis & Repair Procedure
NOTE: If any following DTC is also present, repair it first and then proceed with this
test: DTC P0750
, P0755 , P0760 .

1997 Mazda MX-5 Miata
1997 AUTOMATIC TRANSMISSIONS NC4A-EL Electronic Controls
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Sunday, July 05, 2009 1:35:04 PMPage 13 © 2005 Mitchell Repair Information Company, LLC.

1. Ensure ATF level and condition is okay. Check line pressure and stall speed. See LINE PRESSURE
TEST and STALL SPEED under TESTING in MAZDA NC4A-EL OVERHAUL article. Repair any
components as necessary. If malfunction is not present, go to next step.
2. Inspect 1-2, 2-3 and 3-4 shift solenoid valves. See SOLENOID VALVES
under COMPONENT
TESTING. Repair as needed. If solenoid valves are okay, go to next step.
3. Inspect valve body. Ensure all valves operate smoothly. Repair as needed. If valve body is okay, go to
next step.
4. Clear DTC and retest. See CLEARING CODES
. If code P0732 is still present, replace PCM. If code is
no longer present and symptom still exists, problem may be caused by intermittent clutch slippage.
Further investigation may be required. See MAZDA NC4A-EL OVERHAUL article.
DTC P0733: INCORRECT 3RD GEAR RATIO
Condition
TCM outputs solenoid pattern of 3rd gear when gear ratio is other than 3rd gear. Possible causes are:
Low ATF level.
Direct clutch slippage.
One-way clutch slippage.
Front clutch slippage.
Low line pressure.
Control valve stuck.
Solenoid valve malfunction.
TCM malfunction.
Diagnosis & Repair Procedure
1. Ensure ATF level and condition is okay. Check line pressure and stall speed. See LINE PRESSURE
TEST and STALL SPEED under TESTING in MAZDA NC4A-EL OVERHAUL article. Repair any
components as necessary. If malfunction is not present, go to next step.
2. Inspect 1-2, 2-3 and 3-4 shift solenoid valves. See SOLENOID VALVES
under COMPONENT
TESTING. Repair as needed. If solenoid valves are okay, go to next step.
3. Inspect valve body. Ensure all valves operate smoothly. Repair as needed. If valve body is okay, go to
next step.
4. Clear DTC and retest. See CLEARING CODES
. If DTC P0733 is still present, replace PCM. If code is
no longer present and symptom still exists, problem may be caused by intermittent clutch slippage.
Further investigation may be required. See MAZDA NC4A-EL OVERHAUL article.
DTC P0734: INCORRECT 4TH GEAR RATIO NOTE: If any following DTC is also present, repair it first and then proceed with this
test: DTC P0750
, P0755 , P0760 .

1997 Mazda MX-5 Miata
1997 AUTOMATIC TRANSMISSIONS NC4A-EL Electronic Controls
Microsoft
Sunday, July 05, 2009 1:35:04 PMPage 14 © 2005 Mitchell Repair Information Company, LLC.

Condition
TCM outputs solenoid pattern of 3rd gear when gear ratio is other than 3rd gear. Possible causes are:
Low ATF level.
Band servo slippage.
Front clutch slippage.
Low line pressure.
Control valve stuck.
Solenoid valve malfunction.
TCM malfunction.
Diagnosis & Repair Procedure
1. Ensure ATF level and condition is okay. Check line pressure and stall speed. See LINE PRESSURE
TEST and STALL SPEED under TESTING in MAZDA NC4A-EL OVERHAUL article. Repair any
components as necessary. If malfunction is not present, go to next step.
2. Inspect 1-2, 2-3 and 3-4 shift solenoid valves. See SOLENOID VALVES
under COMPONENT
TESTING. Repair as needed. If solenoid valves are okay, go to next step.
3. Inspect valve body. Ensure all valves operate smoothly. Repair as needed. If valve body is okay, go to
next step.
4. Clear DTC and retest. See CLEARING CODES
. If DTC P0734 is still present, replace PCM. If code is
no longer present and symptom still exists, problem may be caused by intermittent clutch slippage.
Further investigation may be required. See MAZDA NC4A-EL OVERHAUL article.
DTC P0740: TORQUE CONVERTER CLUTCH MALFUNCTION
Condition
TCM outputs TCC signal, but TCC does not operate. Possible causes are:
Low ATF level.
Low line pressure.
Torque converter slippage.
Control valve stuck.
Lock-up solenoid valve malfunction.
TCM malfunction.
Diagnosis & Repair Procedure
NOTE: If any following DTC is also present, repair it first and then proceed with this
test: DTC P0750
, P0755 , P0760 .

1997 Mazda MX-5 Miata
1997 AUTOMATIC TRANSMISSIONS NC4A-EL Electronic Controls
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Sunday, July 05, 2009 1:35:04 PMPage 15 © 2005 Mitchell Repair Information Company, LLC.

Condition
Vehicle speed sensor signal is not input to TCM. Possible causes are:
Vehicle speed sensor malfunction.
Vehicle speedometer sensor malfunction.
Damaged circuits or connectors between sensors and TCM.
Diagnosis & Repair Procedure
1. Ensure all connections are clean and tight. Repair as needed. Turn ignition on. Using voltmeter,
backprobe TCM harness connector. DO NOT disconnect connector. Test drive vehicle.
2. Measure voltage between ground and terminal No. 1P (Green/Red wire) on TCM harness connector.
During test drive voltage should be about 4 volts. When parked, voltage should be less than 1.5 or 7-9
volts. If voltage is within specifications, go to step 5 . If voltage is not within specifications, go to next
step.
3. Turn ignition off. Disconnect negative battery cable. Remove instrument cluster. Disconnect TCM
harness connectors. Ensure continuity exists on Green/Red wire between terminal No. 1P on TCM
connector and terminal No. 2F on instrument cluster harness left connector. Repair as needed. If
continuity exists, go to next step.
4. With combination meter removed, measure voltage between terminals No. 2F and 2D on combination
meter connector using analog voltmeter. Raise and support vehicle. Rotate rear wheels. If voltage pulse is
present, go to next step. If voltage pulse is not present, inspect speedometer cable. Replace as needed. If
cable is okay, replace combination meter or circuit board (as applicable).
5. Clear codes and road test vehicle. Retrieve DTC. If DTC 1720 is still present, replace TCM. If code is no
longer present, problem may be caused by poor connection. Repair as needed.
DTC P1743: TORQUE CONVERTER CLUTCH (TCC) SOLENOID MALFUNCTION
Possible Causes:
Short or open circuit between TCM and solenoid.
TCM malfunction.
Lock-up solenoid malfunction.
Diagnosis & Repair Procedure
1. Ensure all connections are clean and tight. Repair as needed. Turn ignition on. Access TCM connectors.
Using voltmeter, backprobe harness connectors. DO NOT disconnect connectors. Go to next step.
2. Measure voltage between ground and terminal No. 2K (Yellow/Black wire). Battery voltage should be
present with solenoid on and zero volts with solenoid off. If voltage is within specifications, go to step 5 .
If voltage is not within specifications, go to next step.
3. Turn ignition off. Disconnect TCM harness connector. Measure resistance between ground and terminal
No. 2K. If resistance is 13-25 ohms at 68°F (20°C), go to step 5 . If resistance is not 13-25 ohms at 68°F
(20°C),
go to next step.

1997 Mazda MX-5 Miata
1997 AUTOMATIC TRANSMISSIONS NC4A-EL Electronic Controls
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4. Inspect lock-up solenoid and related circuits. See SOLENOID VALVES under COMPONENT
TESTING. Repair as needed. If solenoid valve and related circuits are okay, go to next step.
5. Clear codes and road test vehicle. Retrieve DTC. If DTC P1743 is still present, replace TCM. If code is
no longer present, problem may be caused by poor connection. Repair as needed.
DTC P1765: 3-2 CONTROL SOLENOID VALVE MALFUNCTION
Possible Causes:
Short or open circuit between TCM and solenoid.
TCM malfunction.
3-2 control solenoid malfunction.
Diagnosis & Repair Procedure
1. Ensure all connections are clean and tight. Repair as needed. Turn ignition on. Access TCM connectors.
Using voltmeter, backprobe harness connectors. DO NOT disconnect connectors. Go to next step.
2. Drive vehicle and measure voltage between ground and terminal No. 2M (Blue/Orange wire). Battery
voltage should be present with solenoid on during 3-2 or 4-3 downshift, and zero volts with solenoid off.
If voltage is within specifications, go to step 5 . If voltage is not within specifications, go to next step.
3. Turn ignition off. Disconnect TCM harness connector. Measure resistance between ground and terminal
No. 2M. If resistance is 13-27 ohms at 68°F (20°C), go to step 5 . If resistance is not 13-27 ohms at 68°F
(20°C), go to next step.
4. Inspect 3-2 control clutch solenoid and related circuits. See SOLENOID VALVES
under
COMPONENT TESTING. Repair as needed. If solenoid valve and related circuits are okay, go to next
step.
5. Clear codes and road test vehicle. Retrieve DTC. If DTC P1765 is still present, replace TCM. If code is
no longer present, problem may be caused by poor connection. Repair as needed.
DTC P1790: THROTTLE POSITION (TP) SENSOR MALFUNCTION
Condition
TP sensor voltage is less than one volt or more than 4.9 volts. Possible causes are:
Poor harness connection at TP sensor.
Circuit fault between TP sensor and ECM or TCM.
TP sensor malfunction.
ECM or TCM malfunction.
Diagnosis & Repair Procedure
NOTE: If DTC P0725 is also present, repair it first and then proceed with this test.

1997 Mazda MX-5 Miata
1997 AUTOMATIC TRANSMISSIONS NC4A-EL Electronic Controls
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CLUTCH
1997-98 CLUTCHES Mazda - RWD
DESCRIPTION
All models use a hydraulically operated clutch. On all models except Miata, the clutch release bearing and
clutch release cylinder are combined into a single unit. No routine adjustments are necessary on B2300, B2500,
B3000 and B4000 models.
ADJUSTMENTS
CLUTCH PEDAL FREE PLAY
Miata
Measure clutch pedal free play. See Fig. 1 . See CLUTCH PEDAL FREE PLAY table. If free play is not
within specification, inspect hydraulic and mechanical system components. If adjustment is required, loosen
lock nut and rotate master cylinder push rod to obtain specified free play. Tighten lock nut.
CLUTCH PEDAL FREE PLAY
(1)
CLUTCH PEDAL HEIGHT
Miata
Measure clutch pedal height from bulkhead to front side of pedal pad. See Fig. 1 . See CLUTCH PEDAL
HEIGHT table.
CLUTCH PEDAL HEIGHT
(1)
CLUTCH DISENGAGEMENT HEIGHT
Miata
Measure clutch disengagement height, where clutch disengages, from pedal pad to bulkhead. See Fig. 1 . See
CLUTCH DISENGAGEMENT HEIGHT (MINIMUM)
table.
ApplicationIn. (mm)
Miata0.2-0.5 (5-13)
(1)See Fig. 1 .
ApplicationIn. (mm)
Miata6.89-7.28 (175-185)
(1)Measure to carpet on bulkhead. See Fig. 1 .

1997 Mazda MX-5 Miata
CLUTCH 1997-98 CLUTCHES Mazda - RWD

1997 Mazda MX-5 Miata
CLUTCH 1997-98 CLUTCHES Mazda - RWD
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