Mazda MX-5 Miata (1997+). Manual - part 16

 

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Mazda MX-5 Miata (1997+). Manual - part 16

 

 

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

  

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

  

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

  

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

  

 

 

 

 

 

 

 

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