Diagnostic procedure

WARNING: This page is about a different car, the 2005 Mazda RX-8. However, it is still accessible from the selected car via links, so may be relevant.

DTC P0740 DIAGNOSTIC PROCEDURE

STEP	INSPECTION		ACTION
1	VERIFY FREEZE FRAME DATA HAS BEEN RECORDED Has FREEZE FRAME DATA been recorded?	Yes	Go to the next step.
1		No	Record the FREEZE FRAME DATA on the repair order, then go to the next step.
2	VERIFY RELATED REPAIR INFORMATION AVAILABILITY Verify related Service Bulletins and/or on-line repair information availability. Is any related repair information available?	Yes	Perform repair or diagnosis according to the available repair information. If the vehicle is not repaired, go to the next step.
2		No	Go to the next step.
3	INSPECT ATF CONDITION Turn the ignition switch to the LOCK position. Inspect ATF condition. Clear red: Normal Milky: Water mixed in fluid Reddish brown: Deteriorated ATF Is it normal? (See AUTOMATIC TRANSMISSION FLUID (ATF) CONDITION INSPECTION .)	Yes	Go to the next step.
3		No	If the ATF color milky or reddish brown, replace ATF, then go to Step 5. (See AUTOMATIC TRANSMISSION FLUID (ATF) REPLACEMENT .)
4	INSPECT ATF LEVEL Start the engine. Warm up AT. Is the ATF level within the specification? (See AUTOMATIC TRANSMISSION FLUID (ATF) LEVEL INSPECTION .)	Yes	Go to the next step.
4		No	Add ATF to the specified level, then go to Step 9. (See AUTOMATIC TRANSMISSION FLUID (ATF) LEVEL INSPECTION .)
5	INSPECT LINE PRESSURE Start the engine. Measure each line pressure. Specification D, M range Idle: 320-450 kPa {3.3-4.6 kgf/cm ² , 46-65 psi} Stall: 1,130-1,330 kPa {11.5-13.6 kgf/cm ² , 164-193 psi} R position Idle: 380-580 kPa {3.9-5.9 kgf/cm ² , 55-84 psi} Stall: 1,470-1,700 kPa {15.0-17.3 kgf/cm ² , 213-247 psi} P, N position Idle: 380-580 kPa {3.9-5.9 kgf/cm ² , 55-84 psi} Are the line pressure measurements within the specifications? (See LINE PRESSURE TEST .)	Yes	Go to the next step.
5		No	Inspect or replace the applicable part according to the line pressure test results, then go to Step 9.
6	CLICK TEST OF SOLENOID VALVES Turn the ignition switch to the LOCK position. Disconnect the AT solenoid valve connector. Apply battery voltage to the AT solenoid valve connector terminals. TCC solenoid valve: G pressure control solenoid valve: A Verify the click sounds of the TCC solenoid valve and pressure control solenoid valve. Are there click sounds?	Yes	Go to the next step.
6		No	Replace the TCC solenoid valve or the pressure control solenoid valve, then go to Step 9. (See CONTROL VALVE BODY REMOVAL .) (See CONTROL VALVE BODY INSTALLATION .)
7	INSPECT DIFFERENCE BETWEEN ENGINE SPEED AND TURBINE SPEED Inspect difference between the engine speed and turbine speed during TCC operation in 4GR. Drive the vehicle under the following conditions: TR switch position: D range Gear position: 4GR TCC solenoid valve: ON Is difference between the engine speed (RPM PID) and turbine speed normal? Difference 99 rpm or less	Yes	Go to the next step.
7		No	Replace the torque converter, then go to Step 9. (See AUTOMATIC TRANSMISSION REMOVAL/INSTALLATION .)
8	INSPECT OPERATION OF EACH VALVE AND SPRING Remove the control valve body. Disassemble the control valve body. Is operation of each valve and return spring normal?	Yes	Replace the torque converter, then go to the next step.
8		No	Replace the control valve body, then go to the next step. (See CONTROL VALVE BODY REMOVAL .) (See CONTROL VALVE BODY INSTALLATION .)
9	VERIFY TROUBLESHOOTING OF DTC P0740 COMPLETED Make sure to reconnect all disconnected connectors. Clear the DTC from the TCM memory using the WDS or equivalent. Start the engine. Warm up AT. Drive the vehicle under the following conditions for 10 s or more. Vehicle speed (VSS PID): Within 10-87 km/h {6-54 mph} Gear position: 4GR TR switch position: D range TCC solenoid valve: ON Is the same DTC present?	Yes	Replace the TCM, then go to the next step. (See TCM REMOVAL/INSTALLATION .)
9		No	Go to the next step.
10	VERIFY AFTER REPAIR PROCEDURE Perform the "After Repair Procedure". (See AFTER REPAIR PROCEDURE .) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE .)
10		No	DTC troubleshooting completed.