1997 MAZDA MX-5 torque spec

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.

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
Microsoft
Sunday, July 05, 2009 1:35:04 PMPage 15 © 2005 Mitchell Repair Information Company, LLC.

1. Inspect ATF level and condition. Correct as needed. If fluid level and condition is okay, check line
pressure. See LINE PRESSURE TEST under TESTING in MAZDA NC4A-EL OVERHAUL article.
Follow repair recommendations if line pressure is not within specifications. If line pressure is okay, go to
next step.
2. Inspect lock-up solenoid. See SOLENOID VALVES
under COMPONENT TESTING. Repair as
needed. If solenoid valve is okay, go to next step.
3. Inspect lock-up control valve in valve body. If valve is okay, go to next step.
4. Using an EC-AT tester connected to TCM, ensure that engine speed and turbine speed during TCC lock-
up in 4th gear are the same. If speeds are different, replace torque converter. If speeds are the same, go to
next step.
5. Clear DTC. See CLEARING CODES
. Retrieve DTC. If DTC P0740 is still present, replace TCM. If
code is no longer present and symptom still exists, problem may be caused by intermittent TCC slippage.
Further investigation may be required. See MAZDA NC4A-EL OVERHAUL article.
DTC P0750: 1-2 SHIFT SOLENOID MALFUNCTION
Possible Causes:
Short or open circuit between TCM and solenoid.
TCM malfunction.
Shift 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. 2E (Blue/Yellow wire) on TCM connector. During
test drive, voltage should be less than one volt when solenoid is off and battery voltage when solenoid is
on. See SOLENOID OPERATION
table under TCM OUTPUT DEVICES. If voltage is within
specification, go to step 5 . If voltage is not within specification, go to next step.
3. Turn ignition off. Disconnect TCM harness connector. Measure resistance between ground and terminal
No. 2E. 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 1-2 shift 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 DTC and road test vehicle. Retrieve DTC. If DTC P0750 is still present, replace TCM. If code is no
longer present, system is okay.
DTC P0755: 2-3 SHIFT SOLENOID MALFUNCTION
Possible Causes:
Short or open circuit between TCM and solenoid.
TCM malfunction.

1997 Mazda MX-5 Miata
1997 AUTOMATIC TRANSMISSIONS NC4A-EL Electronic Controls
Microsoft
Sunday, July 05, 2009 1:35:04 PMPage 16 © 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
Microsoft
Sunday, July 05, 2009 1:35:04 PMPage 18 © 2005 Mitchell Repair Information Company, LLC.

Fig. 2: Prying Out Axle Shaft
Courtesy of MAZDA MOTORS CORP.
Installation
To install, reverse removal procedure. Install NEW clip. Measure outer diameter of clip after installing. See Fig.
3 . Replace clip if it exceeds specification. With the ends of clip facing upward, push axle shaft into deferential.
After installation, pull outward on double offset joint outer ring and verify that axle shaft is securely held by
clip. Install NEW locknut and stake it as shown. See Fig. 4
. Tighten all bolts and nuts to specification. See
TORQUE SPECIFICATIONS
.
CAUTION: Sharp edges of axle shaft snap ring can slice or puncture oil seal. Be
careful when installing axle shaft to differential.

1997 Mazda MX-5 Miata
1997-2001 DRIVE AXLES Axle Shafts - MX-5 Miata
Microsoft
Sunday, July 05, 2009 1:51:37 PMPage 3 © 2005 Mitchell Repair Information Company, LLC.

Fig. 15: Installing Boot Band
Courtesy of MAZDA MOTORS CORP.
AXLE SHAFT BOOT IDENTIFICATION
LUBRICATION SPECIFICATION
AXLE SHAFT LENGTH
TORQUE SPECIFICATIONS
ApplicationWheel Side Diameter - In. (mm)
Differential Side Diameter - In.
(mm)
Miata3.58 (90.8)3.44 (87.4)
ApplicationQuantify
Differential Side CV Joint Boot3-3.71 oz. (85-105 g)
Wheel Side CV Joint Boot1.94-2.65 oz. (55-75 g)
ApplicationIn. (mm)
199730.21-30.60 (767.3-777.3)
1999-200130.42-30.81 (772.6-782.6)

1997 Mazda MX-5 Miata
1997-2001 DRIVE AXLES Axle Shafts - MX-5 Miata
Microsoft
Sunday, July 05, 2009 1:51:38 PMPage 15 © 2005 Mitchell Repair Information Company, LLC.

TORQUE SPECIFICATIONS
ApplicationFt. Lbs. (N.m)
Axle Shaft Lock Nut
1997160-216 (216-294)
1999-2001174-235 (236-318)
Brake Caliper Mounting Bolt37-50 (50-68)
Lower Control Arm Bolt/Nut47-54 (64-73)
Wheel Lug Nuts66-86 (89-117)

1997 Mazda MX-5 Miata
1997-2001 DRIVE AXLES Axle Shafts - MX-5 Miata
Microsoft
Sunday, July 05, 2009 1:51:38 PMPage 16 © 2005 Mitchell Repair Information Company, LLC.