1997 MAZDA MX-5 engine

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
Microsoft
Sunday, July 05, 2009 1:35:03 PMPage 7 © 2005 Mitchell Repair Information Company, LLC.

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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2. Measure voltage between terminal No. 1G (Green wire) and No. 2P (Black/Light Blue wire) on TCM
connector. Voltage should be about 3.3 volts at 77°F (25°C). If voltage is within specifications, go to step
6 . If voltage is not within specifications, go to next step.
3. Turn ignition off. Disconnect TCM harness connector. Measure resistance between terminals No. 1G and
No. 2P. See TFT SENSOR SPECIFICATIONS
table. If resistance is within specification, go to step 6 .
If resistance is not within specification, go to next step.
4. Inspect TFT sensor. Disconnect TFT sensor harness connector. Measure resistance between connector
terminals. See TFT SENSOR SPECIFICATIONS
table. If resistance is within specification, go to step
6 . If resistance is not within specification, replace TFT sensor.
5. Check continuity of circuits between TFT sensor and TCM. See appropriate wiring diagram in WIRING
DIAGRAMS . Repair as needed. If circuit is okay, go to next step.
6. Reconnect all harness connectors. Road test vehicle. Retrieve DTC. If code P0710 or P0711 is still
present, replace TCM. If code is no longer present, system is okay.
TFT SENSOR SPECIFICATIONS
DTC P0715: INPUT/TURBINE SPEED SENSOR
Condition
Input/Turbine speed sensor signal is not input to TCM when vehicle is moving. Possible causes for condition
are:
Input/Turbine speed sensor malfunction.
Damaged wiring or connectors between turbine speed sensor and TCM.
TCM malfunction.
Diagnosis & Repair Procedure
1. Turn ignition on. Using voltmeter, backprobe TCM harness connector. DO NOT disconnect connector.
Measure AC voltage between terminals No. 2J (positive) and No. 2L (negative). Voltage should be 0-.1
volts when idling and zero with engine stopped. If voltage is within specification, go to step 5 . If voltage
is not within specification, go to next step.
2. Turn ignition off. Disconnect TCM harness connector. Check for continuity between terminals No. 2J
(Yellow/Green wire) and No. 2L (Yellow/Blue wire). If continuity is present, go to step 5 . If continuity
is not present, go to next step.
3. Inspect sensor. See INPUT/TURBINE SPEED SENSOR
under COMPONENT TESTING. Repair as
needed. If sensor is okay, go to next step.
4. Check continuity of circuits between input/turbine speed sensor and TCM. See appropriate wiring
dia
gram in WIRING DIAGRAMS . Repair as needed. If circuits are okay, go to next step.
Fluid Temperaturek/ohms
68°F (20°C)2.5
140°F (60°C).6
176°F (80°C).35

1997 Mazda MX-5 Miata
1997 AUTOMATIC TRANSMISSIONS NC4A-EL Electronic Controls
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5. Reconnect all harness connectors. Road test vehicle. Retrieve DTC. If code P0715 is still present, replace
PCM. If code is no longer present, system is okay.
DTC P0725: ENGINE SPEED INPUT CIRCUIT MALFUNCTION
Condition
Engine speed input signal is not input to TCM. Possible causes are:
Crankshaft position sensor malfunction.
Damaged wiring or connectors between ECM and TCM.
ECM malfunction.
TCM malfunction.
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.
2. Measure voltage between ground and terminal No. 1N (White wire) on TCM harness connector. Voltage
should be zero or 4.5-5.5 volts with engine stopped or 2-3 volts with engine idling. If voltage is within
specifications, go to step 7 . If voltage is not within specifications, go to next step.
3. Ignition off. Measure continuity between terminal No. 1N (White wire) on TCM harness connector and
terminal No. 4F (White wire) on ECM harness connector. If continuity is not present, repair wiring then
go to step 7 .
4. Using voltmeter, backprobe ECM harness connector. Measure voltage between ground and terminal No.
4H (Yellow/White wire). Voltage should be less than one volt with engine stopped or greater than one
volt with engine idling. If voltage is within specifications, go to step 7 . If voltage is not within
specifications, go to next step.
5. Inspect crankshaft position sensor. See appropriate SYSTEM & COMPONENT TESTS article in
ENGINE PERFORMANCE. Replace as needed. If sensor is okay, go to next step.
6. Turn ignition off. Using ohmmeter, backprobe TCM harness connector. DO NOT disconnect connector.
Measure resistance between terminals 1N (White wire) and 2P (Black/Light Green wire). If resistance is
7.2-8.0 ohms, go to next step. If resistance is not 7.2-8.0 ohms, replace TCM.
7. Reconnect all harness connectors. Road test vehicle. Retrieve DTC. If code P0725 is still present, replace
TCM. If code is no longer present, problem is intermittent.
DTC P0731: INCORRECT 1ST GEAR RATIO NOTE: If DTC P0335 is also present, repair it first and then proceed with this test. Go to
appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE and
perform test.
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 12 © 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.

1. Ensure all connections are clean and tight. Repair as needed. Ensure that TP sensor is adjusted correctly.
See appropriate ON-VEHICLE ADJUSTMENTS article in ENGINE PERFORMANCE. 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. 2T (Red/Black wire) on TCM harness connector. With
throttle closed, voltage should be .1-1.1 volts. With wide open throttle, voltage should be 3.1-4.4 volts. If
voltage is within specification, go to step 5 . If voltage is not within specification, go to next step.
3. Measure voltage between ground and terminal No. 2A (Light Green/White wire) on TCM harness
connector. With ignition on, voltage should be 4.5-5.5 volts. With ignition off, voltage should be zero
volts. If voltage is within specification, go to step 5 . If voltage is not within specification, go to next step.
4. Inspect circuits between TP sensor and TCM. See appropriate wiring diagram under WIRING
DIAGRAMS . Repair as needed. If circuits are okay between sensor and TCM, go to next step.
5. Clear codes, and road test vehicle. Retrieve DTC. If DTC P1790 is still present, replace TCM. If code is
no longer present, system is okay.
DTC P1795: IDLE SWITCH OPEN OR SHORT
Condition
Closed throttle position switch is ON and TP sensor position is closed. Possible causes are:
Damaged wiring or connectors between closed throttle position switch and TCM.
Closed throttle position switch malfunction.
TCM 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. 1O (Red wire) on TCM harness connector. With
throttle closed, battery voltage should be present. With wide open throttle, voltage should be zero volts. If
voltage is within specification, go to step 5 . If voltage is not within specification, go to next step.
3. Inspect circuits between closed throttle position switch and TCM. See appropriate wiring diagram under
WIRING DIAGRAMS
. Repair as needed. If circuits are okay between sensor and TCM, go to next
step.
4. Disconnect battery negative cable. Disconnect closed throttle position switch connector. Check for
continuity between closed throttle position switch terminals. If continuity exists, go to next step. If
continuity does not exist, replace or adjust throttle position sensor.
5. Clear codes, and road test vehicle. Retrieve DTC. If DTC P1795 is still present, replace TCM. If code is
no longer present, problem is intermittent. Further investigation is required.
COMPONENT TESTING
NOTE: For connector terminal identification, see COMPONENT CONNECTOR

1997 Mazda MX-5 Miata
1997 AUTOMATIC TRANSMISSIONS NC4A-EL Electronic Controls
Microsoft
Sunday, July 05, 2009 1:35:04 PMPage 20 © 2005 Mitchell Repair Information Company, LLC.

Remove master cylinder to gain access to push rod. To check screw adjustment, fabricate a gauge. See Fig. 1.
With engine running and vacuum line connected to booster, place gauge against master cylinder mounting
surface of booster. Adjust push rod screw by turning it until end of screw just touches inner edge of gauge slot.
Fig. 1: Adjusting Brake Booster Push Rod (B2300, B3000 & B4000)

Courtesy of FORD MOTOR CO.
REAR BRAKE SHOES ADJUSTMENT
B2300, B3000 & B4000
NOTE: Rear brakes are self-adjusting and require manual adjustment only if brake
shoes have been replaced.

1997 Mazda MX-5 Miata
BRAKE SYSTEM 1995-97 BRAKES Mazda - Disc & Drum
Microsoft
Sunday, July 05, 2009 1:51:02 PMPage 2 © 2005 Mitchell Repair Information Company, LLC.

1. On models with rear disc brakes, depress brake pedal several times. On models with rear drum brakes,
start engine and depress brake pedal several times while vehicle is moving in reverse. Stop engine.
2. On Miata, pull parking brake lever with a force of 44 lbs. (20 kg). On all other models, pull parking brake
lever with a force of 22 lbs. (10 kg). If stroke is 7-9 notches on Miata or 5-7 notches on all others, parking
brake is properly adjusted. If stroke is not as specified, raise and support rear of vehicle. Release parking
brake lever.
3. Rotate cable adjusting nut at lever end of cable, located under console cover, until stroke is within
specification. Ensure rear brakes do not drag. Ensure parking brake warning light illuminates when brake
lever is pulled one notch.
Millenia
1. Depress brake pedal several times. Pull parking brake lever with a force of 22 lbs. (10 kg). If stroke is 3-5
notches, parking brake is properly adjusted. If stroke is not 3-5 notches, raise and support rear of vehicle.
Release parking brake lever.
2. Remove parking brake lever cover. Rotate cable adjusting nut at lever end of cable until stroke is within
specification. Ensure rear brakes do not drag. Ensure parking brake warning light illuminates when brake
lever is pulled one notch.
MPV (1995-96)
1. Depress brake pedal several times. Pull parking brake lever with a force of 22 lbs. (10 kg). If stroke is 3-6
notches, parking brake is properly adjusted. If stroke is not as specified, raise and support rear of vehicle.
Release parking brake lever.
2. Remove adjusting nut clip and rotate cable adjusting nut at lever end of cable, located under console
cover, until stroke is within specification. Ensure rear brakes do not drag. Ensure parking brake warning
light illuminates when brake lever is pulled one notch.
MPV (1997)
1. Depress brake pedal several times. Pull parking brake lever with a force of 44 lbs. (20 kg). If stroke is 6-9
notches, parking brake is properly adjusted. If stroke is not as specified, raise and support rear of vehicle.
Release parking brake lever.
2. Remove adjusting nut clip and rotate cable adjusting nut at lever end of cable, located under console
cover, until stroke is within specification. Ensure rear brakes do not drag. Ensure parking brake warning
light illuminates when brake lever is pulled one notch.
RX7
1. Depress brake pedal several times. Pull parking brake lever with a force of 22 lbs. (10 kg). If stroke is 7-
10 notches, parking brake is properly adjusted. If stroke is not 7-10 notches, raise and support rear of
vehicle. Release parking brake lever.
2. Rotate cable adjusting nut at lever end of cable, located under console cover, until stroke is within
specification. Ensure rear brakes do not drag. Ensure parking brake warning light illuminates when brake
lever is pulled one notch.

1997 Mazda MX-5 Miata
BRAKE SYSTEM 1995-97 BRAKES Mazda - Disc & Drum
Microsoft
Sunday, July 05, 2009 1:51:02 PMPage 5 © 2005 Mitchell Repair Information Company, LLC.