1997 MAZDA MX-5 Engine control

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

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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 .

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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
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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

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GENERAL INFORMATION
Computer Relearn Procedures
COMPUTER RELEARN PROCEDURES
Vehicles equipped with engine or transmission computers may require a relearn procedure after vehicle battery
is disconnected. Many vehicle computers memorize and store vehicle operation patterns for optimum
driveability and performance. When vehicle battery is disconnected, this memory is lost. The computer will use
default data until new data from each key start is stored. As computer memorizes vehicle operation for each
new key start, driveability is restored. Vehicle computers may memorize vehicles operation patterns for 40 of
more key starts.
Customers often complain of driveability problems during relearn stage because vehicle acts differently then
before being serviced. Depending on type and make of vehicle and how it is equipped, the following complaints
(driveability problems) may exist:
Harsh Or Poor Shift Quality
Rough Or Unstable Idle
Hesitation Or Stumble
Rich Or Lean Running
Poor Fuel Mileage
These symptoms and complaints should disappear after a number of drive cycles have been memorized. To
reduce the possibility of complaints, after any service which requires battery power to be disconnected, vehicle
should be road tested.
GENERIC COMPUTER RELEARN PROCEDURES
Some manufacturers identify a specific relearn procedure which will help establish suitable driveability during
relearn stage. These procedures are especially important if vehicle is equipped with and electronically
controlled automatic transmission or transaxle. Always complete procedure before returning vehicle to
customer. The following general procedures are to be used if driveability problems are encountered after power
loss or battery has been disconnected. These procedures may provide an aid in eliminating these problems.
Automatic Transmission
Set parking brake, start engine in "P" or "N" position. Warm-up vehicle to normal operating temperature
or until cooling fan cycles.
Allow vehicle to idle for one minute in "N" position. Select "D" and allow engine to idle for one minute.
Accelerate at normal throttle position (20-50%) until vehicle shifts into top gear.
Cruise at light to medium throttle.
Decelerate to a stop, allowing vehicle to downshift, and use brakes normally.
Process may be repeated as necessary.

1997 Mazda MX-5 Miata
GENERAL INFORMATION Computer Relearn Procedures

1997 Mazda MX-5 Miata
GENERAL INFORMATION Computer Relearn Procedures
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Fig. 5: Exploded View Of Rear Axle Shaft (MPV)
Courtesy of MAZDA MOTORS CORP.
DIFFERENTIAL ASSEMBLY
Removal (Front MPV 4WD)
1. Raise and support vehicle. Remove engine skid plate. See Fig. 6 . Drain front differential fluid. Remove
tie rod ends and lower control arms. Remove front axle shafts. See AXLE SHAFTS
- FRONT article.
2. Mark drive shaft and differential carrier flanges for reassembly reference, and remove drive shaft from
differential carrier. See Fig. 6
. Disconnect Automatic Free Wheel (AFW) vacuum hoses and electrical
connector.
3. Place floor jack under differential assembly. Remove differential-to-chassis mounting bolts and AFW
extension housing mounting nuts. Remove differential and AFW extension housing from vehicle.
Remove AFW assembly from left side of differential housing. Pull drive coupler from carrier. Remove
differential carrier-to-housing bolts. Remove differential carrier.
Installation
To install, reverse removal procedure. Apply sealant to carrier mating flange. Align marks made during
removal. Refill differential with lubricant. Tighten all nuts and bolts to specification. See TORQUE
SPECIFICATIONS.

1997 Mazda MX-5 Miata
1997-98 DRIVE AXLES Differentials & Drive Axles - MPV & MX-5 Miata
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1997 MAZDA
MX-5 Miata
BUZZERS, RELAYS & TIMERS
BUZZERS, RELAYS & TIMERS
CIRCUIT PROTECTION DEVICES
CIRCUIT PROTECTION DEVICES
CONTROL UNITS
CONTROL UNITS
ComponentComponent Location
A/C RelayIn right front of engine compartment, near radiator. See Fig. 1 .
Condenser Fan RelayIn right front of engine compartment, near radiator. See Fig. 1 .
Cooling Fan RelayIn main fuse/relay block.
Flasher UnitBehind left side of dash. See Fig. 2 .
Fuel Pump RelayUnder left side of dash. See Fig. 2 .
Headlamp RelayOn left rear corner of front inner fender panel. See Fig. 1 .
Horn RelayOn left rear corner of front inner fender panel. See Fig. 1 .
INT RelayIntegral with windshield wiper & washer switch.
Main RelayIn left rear corner of engine compartment, in main fuse/relay block.
Power Antenna RelayIn right rear of vehicle, attached to power antenna.
Rear Window Defogger
RelayIn center rear of trunk compartment. See Fig. 3 .
Retractable Headlamp RelayBehind left side of dash.
TNS RelayIn left rear corner of engine compartment, on inner fender panel. See Fig.
1 .
Warning UnitBehind left side of dash. See Fig. 2 .
ComponentComponent Location
Fuse Block (Front)Behind left side of dash. See Fig. 2 .
Fuse Block (Rear)On right rear side of luggage compartment. See Fig. 3 .
Main Fuse BlockOn right rear corner of engine compartment, near firewall. See Fig. 1 .
ComponentComponent Location
ABS Control ModuleBehind passenger's seat. See Fig. 3 .
ABS Control UnitIn right rear corner of engine compartment.
Cruise Control ModuleUnder left side of dash above fuse block. See Fig. 2 .
Daytime Running Lamp (DRL) Control ModuleOn bracket, behind left side of dash. See Fig. 2 .
Engine Control Module (ECM)Behind passenger's seat. See Fig. 3 .

1997 Mazda MX-5 Miata
1997 MAZDA MX-5 Miata

1997 Mazda MX-5 Miata
1997 MAZDA MX-5 Miata
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