DTC P0731[FN4A-EL]

DTC P0731	Gear 1 incorrect (incorrect gear ratio detected)
DETECTION CONDITION	• The PCM monitors the revolution ratio of the forward clutch drum revolution to differential gear case revolution when the following monitoring conditions are met. If the revolution ratio is 2.185 (ZY)/2.157 (Z6, LF) or less, the PCM determines that there is a malfunction. Monitoring condition: ― Engine running ― ATF temperature 20 °C {68 °F} or more ― Driving in 1GR in D or M range ― Turbine speed within 225—4,987 rpm ― Accelerator opening angle 3.17% or more (ZY) ― Throttle opening angle 2.66% or more (Z6) ― Accelerator opening angle 3.07% or more (LF) ― Differential gear case (output) revolution speed 35 rpm or more ― None of the following DTCs are present: P0706, P0707, P0708, P0712, P0713, P0715, P0720, P0751, P0752, P0753, P0756, P0757, P0758, P0761, P0762, P0763, P0766, P0767, P0768, P0771, P0772, P0773 Diagnostic support note: • This is a continuous monitor (CCM). • The MIL does not illuminate. • The AT warning light illuminates if the PCM detects the above malfunction condition during the first drive cycle. • FREEZE FRAME DATA is not available. • A PENDING CODE is not available. • The DTC is 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 malfunction • PCM malfunction

DTC P0731

Gear 1 incorrect (incorrect gear ratio detected)

DETECTION CONDITION

• The PCM monitors the revolution ratio of the forward clutch drum revolution to differential gear case revolution when the following monitoring conditions are met. If the revolution ratio is 2.185 (ZY)/2.157 (Z6, LF) or less, the PCM determines that there is a malfunction.

Monitoring condition:

― Engine running

― ATF temperature 20 °C {68 °F} or more

― Driving in 1GR in D or M range

― Turbine speed within 225—4,987 rpm

― Accelerator opening angle 3.17% or more (ZY)

― Throttle opening angle 2.66% or more (Z6)

― Accelerator opening angle 3.07% or more (LF)

― Differential gear case (output) revolution speed 35 rpm or more

― None of the following DTCs are present: P0706, P0707, P0708, P0712, P0713, P0715, P0720, P0751, P0752, P0753, P0756, P0757, P0758, P0761, P0762, P0763, P0766, P0767, P0768, P0771, P0772, P0773

Diagnostic support note:

• This is a continuous monitor (CCM).

• The MIL does not illuminate.

• The AT warning light illuminates if the PCM detects the above malfunction condition during the first drive cycle.

• FREEZE FRAME DATA is not available.

• A PENDING CODE is not available.

• The DTC is 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 malfunction

• PCM malfunction

STEP	INSPECTION	ACTION
1	VERIFY RELATED SERVICE INFORMATION AVAILABILITY • Verify related Service Information availability. • Is any related Service Information available?	Yes	Perform repair or diagnosis according to the available Service Information. • If the vehicle is not repaired, go to the next step.
No	Go to the next step.
2	INSPECT ATF CONDITION • Inspect the ATF condition. (See AUTOMATIC TRANSAXLE FLUID (ATF) INSPECTION[FN4A-EL].) • Is it normal?	Yes	Go to the next step.
No	Replace the transaxle, then go to Step 8.
3	INSPECT ATF LEVEL • Start the engine. • Warm up the ATX. • Is the ATF level within the specification? (See AUTOMATIC TRANSAXLE FLUID (ATF) INSPECTION[FN4A-EL].)	Yes	Go to the next step.
No	Add ATF to the specified level, then go to Step 8.
4	INSPECT SHIFT SOLENOID A • Perform operation inspection. (See SOLENOID VALVE INSPECTION[FN4A-EL].) • Verify the click sound of shift solenoid A when applying B+ to transaxle terminal A. • Was a click heard from solenoids?	Yes	Go to the next step.
No	Replace the solenoid that you could not hear a click sound, then go to Step 8. (See SOLENOID VALVE REMOVAL/INSTALLATION[FN4A-EL].)
5	INSPECT LINE PRESSURE • Start the engine. • Measure the line pressures. (See MECHANICAL SYSTEM TEST[FN4A-EL].) • Are the line pressures within the specifications?	Yes	Go to the next step.
No	All ranges: Replace the oil pump, then go to Step 8. Any ranges: Replace the control valve body, then go to Step 8. (See CONTROL VALVE BODY REMOVAL[FN4A-EL].) (See CONTROL VALVE BODY INSTALLATION[FN4A-EL].)
6	INSPECT STALL SPEED • Measure the stall speed in D range. (See MECHANICAL SYSTEM TEST[FN4A-EL].) • Is the stall speed within the specification?	Yes	Go to the next step.
No	Replace the automatic transaxle, then go to Step 8. (See AUTOMATIC TRANSAXLE REMOVAL/INSTALLATION (ZY, Z6)[FN4A-EL].) (See AUTOMATIC TRANSAXLE REMOVAL/INSTALLATION (LF)[FN4A-EL].)
7	INSPECT FREQUENCY OF INPUT/TURBINE SPEED SENSOR WHEN DRIVING VEHICLE • Turn the ignition switch to the LOCK position. • Connect the M-MDS. • Start the engine. • Measure the frequency of input/turbine speed sensor while driving vehicle under the following conditions: ― Vehicle speed (VSS PID): 20 km/h {12 mph} ― Drive in the D range, 1GR ― Throttle opening angle (THOP PID): approx. 25% • Was the frequency of the input/turbine speed sensor at approx. 1,100 Hz?	Yes	Go to the next step.
No	Replace the control valve body, then go to the next step. (See CONTROL VALVE BODY REMOVAL[FN4A-EL].) (See CONTROL VALVE BODY INSTALLATION[FN4A-EL].)
8	VERIFY REPAIR OF DTC P0731 • Make sure to reconnect all the disconnected connectors. • Clear the DTC using the M-MDS. • Start the engine. • Warm up the transaxle. • Drive the vehicle under the following conditions at least 4 times for more than 1 s: ― ATF temperature: 20 °C {68 °F} or more ― Drive in the D range, 1GR ― Accelerator opening angle (APP PID): 3.17% or more (ZY) ― Throttle opening angle (THOP PID): 2.66% or more (Z6) ― Accelerator opening angle (APP PID): 3.07% or more (LF) ― Vehicle speed (VSS PID): 4 km/h {3 mph} or more • Are any DTCs present?	Yes	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION[ZJ, ZY, Z6].) (See PCM REMOVAL/INSTALLATION[LF, L3].)
No	Go to the next step.
9	VERIFY AFTER REPAIR PROCEDURE • Perform the "After Repair Procedure". (See AFTER REPAIR PROCEDURE[FN4A-EL].) • Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE[FN4A-EL].)
No	DTC troubleshooting completed.

STEP

INSPECTION

ACTION

VERIFY RELATED SERVICE INFORMATION AVAILABILITY

• Verify related Service Information availability.

• Is any related Service Information available?

Yes

Perform repair or diagnosis according to the available Service Information.

• If the vehicle is not repaired, go to the next step.

Go to the next step.

INSPECT ATF CONDITION

• Inspect the ATF condition.

(See AUTOMATIC TRANSAXLE FLUID (ATF) INSPECTION[FN4A-EL].)

• Is it normal?

Yes

Go to the next step.

Replace the transaxle, then go to Step 8.

INSPECT ATF LEVEL

• Start the engine.

• Warm up the ATX.

• Is the ATF level within the specification?

(See AUTOMATIC TRANSAXLE FLUID (ATF) INSPECTION[FN4A-EL].)

Yes

Go to the next step.

Add ATF to the specified level, then go to Step 8.

INSPECT SHIFT SOLENOID A

• Perform operation inspection.

(See SOLENOID VALVE INSPECTION[FN4A-EL].)

• Verify the click sound of shift solenoid A when applying B+ to transaxle terminal A.

• Was a click heard from solenoids?

Yes

Go to the next step.

Replace the solenoid that you could not hear a click sound, then go to Step 8.

(See SOLENOID VALVE REMOVAL/INSTALLATION[FN4A-EL].)

INSPECT LINE PRESSURE

• Start the engine.

• Measure the line pressures.

(See MECHANICAL SYSTEM TEST[FN4A-EL].)

• Are the line pressures within the specifications?

Yes

Go to the next step.

All ranges: Replace the oil pump, then go to Step 8.

Any ranges: Replace the control valve body, then go to Step 8.

(See CONTROL VALVE BODY REMOVAL[FN4A-EL].)

(See CONTROL VALVE BODY INSTALLATION[FN4A-EL].)

INSPECT STALL SPEED

• Measure the stall speed in D range.

(See MECHANICAL SYSTEM TEST[FN4A-EL].)

• Is the stall speed within the specification?

Yes

Go to the next step.

Replace the automatic transaxle, then go to Step 8.

(See AUTOMATIC TRANSAXLE REMOVAL/INSTALLATION (ZY, Z6)[FN4A-EL].)

(See AUTOMATIC TRANSAXLE REMOVAL/INSTALLATION (LF)[FN4A-EL].)

INSPECT FREQUENCY OF INPUT/TURBINE SPEED SENSOR WHEN DRIVING VEHICLE

• Turn the ignition switch to the LOCK position.

• Connect the M-MDS.

• Start the engine.

• Measure the frequency of input/turbine speed sensor while driving vehicle under the following conditions:

― Vehicle speed (VSS PID): 20 km/h {12 mph}

― Drive in the D range, 1GR

― Throttle opening angle (THOP PID): approx. 25%

• Was the frequency of the input/turbine speed sensor at approx. 1,100 Hz?

Yes

Go to the next step.

Replace the control valve body, then go to the next step.

(See CONTROL VALVE BODY REMOVAL[FN4A-EL].)

(See CONTROL VALVE BODY INSTALLATION[FN4A-EL].)

VERIFY REPAIR OF DTC P0731

• Make sure to reconnect all the disconnected connectors.

• Clear the DTC using the M-MDS.

• Start the engine.

• Warm up the transaxle.

• Drive the vehicle under the following conditions at least 4 times for more than 1 s:

― ATF temperature: 20 °C {68 °F} or more

― Drive in the D range, 1GR

― Accelerator opening angle (APP PID): 3.17% or more (ZY)

― Throttle opening angle (THOP PID): 2.66% or more (Z6)

― Accelerator opening angle (APP PID): 3.07% or more (LF)

― Vehicle speed (VSS PID): 4 km/h {3 mph} or more

• Are any DTCs present?

Yes

Replace the PCM, then go to the next step.

(See PCM REMOVAL/INSTALLATION[ZJ, ZY, Z6].)

(See PCM REMOVAL/INSTALLATION[LF, L3].)

Go to the next step.

VERIFY AFTER REPAIR PROCEDURE

• Perform the "After Repair Procedure".

(See AFTER REPAIR PROCEDURE[FN4A-EL].)

• Are any DTCs present?

Yes

Go to the applicable DTC inspection.

(See DTC TABLE[FN4A-EL].)

DTC troubleshooting completed.