DTC P0731 (EXCEPT FOR GENERAL (L.H.D.) SPECS. SPORT AT) [FN4A-EL]

id0502a18019a6

DTC P0731

Gear 1 incorrect (Incorrect Gear Ratio Detected)

DETECTION CONDITION

• PCM monitors revolution ratio of forward clutch drum revolution to differential gear case revolution when the following monitoring conditions are met. If revolution ratio is below 2.157, PCM determines that there is malfunction.
Monitoring condition:
- ATF temperature 20 °C {68 °F} or above.
- Driving in 1GR in D range.
- Engine run.
- Turbine speed within 225-4,988 rpm.
- Throttle opening angle 5.67% or above
- Differential gear case (output) revolution speed 35 rpm or above.
- Any of the following not generated: DTC P0500, P0706, P0707, P0708, P0712, P0713, P0715, P0751, P0752, P0753, P0756, P0757, P0758, P0761, P0762, P0763, P0766, P0767, P0768, P0771, P0772, P0773.
Diagnostic support note:
• This is a continuous monitor (CCM).
• MIL does not illuminate.
• HOLD indicator light or AT warning light flashes if PCM detects the above malfunction condition during first drive cycle.
• FREEZE FRAME DATA is not available.
• Pending code is not available.
• DTC stored in the PCM memory.

POSSIBLE CAUSE

• ATF level low
• Deteriorated ATF
• Shift solenoid A stuck
• Pressure control solenoid stuck
• Line pressure low
• One-way clutch slipping
• Forward clutch slipping
• Control valve stuck
• Oil pump
• PCM malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION

1

VERIFY RELATED REPAIR INFORMATION AVAILABILITY

• Check for related Service Bulletins availability.
• Is any related repair information available?
Yes
Perform repair or diagnosis according to available repair information.
No
Go to next step.
2

CHECK ATF CONDITION

• Check ATF condition.
• Is it okay?
Yes
Go to next step.
No
Replace transaxle, then go to Step 8.
3

CHECK ATF LEVEL

• Start engine.
• Warm up ATX.
• Is ATF level within specification?
Yes
Go to next step.
No
Adjust ATF level, then go to Step 8.
4

INSPECT SHIFT SOLENOID VALVE A

• Perform inspection of operation. (See SOLENOID VALVE INSPECTION [FN4A-EL].)
• Verify the click sound of shift solenoid A when applying B+ to transaxle connector terminal A.
• Was click heard from solenoids?
Yes
Go to next step.
No
Replace solenoid that you could not hear click sound, then go to Step 8.
5

INSPECT LINE PRESSURE

• Start engine.
• Measure line pressures.

Specification

Idle: 330-470 kPa {3.4-4.7 kgf/cm2, 49-66 psi}

Stall: 1,160-1,320 kPa {11.9-13.4 kgf/cm2, 170-190 psi}

• Is line pressure within specification?
Yes
Go to next step.
No
All ranges: Replace oil pump, then go to Step 8.
Any ranges: Replace control valve body, then go to Step 8. (See CONTROL VALVE BODY REMOVAL [FN4A-EL], CONTROL VALVE BODY INSTALLATION [FN4A-EL].)
6

INSPECT STALL SPEED

• Measure stall speed in D range.
(See Stall Test.)

Specification

2,000-2,600 rpm

• Is stall speed within specification?
Yes
Go to next step.
No
Replace automatic transaxle, then go to Step 8.
7

INSPECT FREQUENCY OF INPUT/TURBINE SPEED SENSOR WHEN DRIVING VEHICLE

• Turn ignition key to OFF.
• Connect WDS or equivalent.
• Start engine.
• Measure frequency of input/turbine speed sensor while driving vehicle under the following conditions:
- Vehicle speed (VSS PID): 20 km/h {12 mph}
- Drive in D range, 1st gear
- Throttle opening angle (TP PID): about 25%
• Was frequency of input/turbine speed sensor at approx. 1,100 Hz?
Yes
Go to next step.
No
Replace control valve body, then go to next step.
8

VERIFY REPAIR OF DTC P0731

• Make sure to reconnect all disconnected connectors.
• Clear DTC using WDS or equivalent.
• Start engine.
• Warm up transaxle.
• Drive vehicle under the following conditions at least 4 times for more than 1 second.
- ATF temperature: 20 °C {68 °F} or above
- Drive in D range, 1st gear
- Throttle opening angle (TP PID): 5.67% or above
- Vehicle speed (VSS PID): 4 km/h {3 mph} or above
• Are any DTCs present?
Yes
Replace PCM, then go to next step.
No
Go to next step.
9

VERIFY AFTER REPAIR PROCEDURE

• Perform "After Repair Procedure".
• Are any DTCs present?
Yes
Go to applicable DTC inspection.
No
Troubleshooting completed.