P0731
DTC P0731 GEAR 1 INCORRECT RATIOCOMPONENT LOCATION:
GENERAL DESCRIPTION
The value of the input shaft speed should be equal to the value of the output shaft speed, when multiplied by the 1st gear ratio, while the transaxle is engaged in the 1st gear. For example, if the input speed is 1000 rpm and the 1st gear ratio is 2.846, then the output speed is about 2846 rpm.
DTC DESCRIPTION
This code is set if the value of input shaft speed is not equal to the value of the output shaft, when multiplied by the 1st gear ratio, while the transaxle is engaged in 1st gear. This malfunction is mainly caused by mechanical troubles such as control valve sticking or solenoid valve malfunctioning rather than an electrical issue.
DTC DETECTING CONDITION:
SCHEMATIC DIAGRAM:
SIGNAL WAVEFORM:
MONITOR SCANTOOL DATA
1. Connect Scantool to data link connector(DLC).
2. Engine "ON".
3. Monitor the "ENGINE SPEED, INPUT SPEED SENSOR(PG-A), OUTPUT SPEED SENSOR(PG-B), GEAR POSITION" parameter on the scan tool.
4. Perform the "STALL TEST" at gear position "1"
OPERATING ELEMENT OF EACH SHIFTING RANGE:
Stall test procedure in D1 and reason
Procedure
1. Warm up the engine
2. Fully depress the brake pedal, then place the transaxle gear lever into "ID" range. Press and hold the accelerator pedal to the floor for no more than eight seconds while observing the engine, input speed, and output speed RPM value.
^ The slippage of 1st gear operating parts can be detected by stall test in D1.
Reason for stall test
1. If there is no mechanical defaults in A/T, all slippage occurs in torque converter.
2. Therefore, engine revolution is output, but input and output speed revolution must be "zero" due to wheel's lock.
3. If 1st gear operating part has faults, input speed revolution will be out of specification.
4. If output speed revolution is output. It means that the foot brake force is not applied fully. Remeasuring is required.
5. Is "STALL TEST" within specification?
YES
^ Go to "W/Harness inspection" procedure.
NO
^ Go to "Component inspection" procedure.
CAUTION:
^ Do not let anybody stand in front of or behind the vehicle while this test is being carried out.
^ Check the A/T fluid level and temperature and the engine coolant temperature.
- Fluid level: At the hot mark on the off level gauge.
- Fluid temperature: 176 °F212 °F(80-100 °C).
- Engine coolant temperature: 176 °F-212 °F(80-100 °C).
^ Chock both rear wheel(left and right).
^ Pull the parking brake lever on with the brake pedal fully depressed.
^ The throttle should not be left fully open for more than eight seconds.
^ If carrying out the staff test two or more times, move the select lever to the "N" position and run the engine at 1,000 rpm to let the A/T fluid cool down before carrying out subsequent tests.
^ Perform stall test on "L" range If the result of stall test on "D" range is out of specifications. "One Way Clutch" is faulty If the result of stall test on "L" range is within specifications.
SIGNAL CIRCUIT INSPECTION
1. Connect Scantool to data link connector(DLC).
2. Engine "ON".
3. Monitor the "ENGINE SPEED, INPUT SPEED SENSOR, OUTPUT SPEED SENSOR, GEAR POSITION" parameter on the Scantool.
4. Perform the "STALL TEST" at gear position "1"
5. Are "INPUT & OUTPUT SPEED SENSOR" within specifications?
YES
^ Go to "Component inspection" procedure.
NO
^ Check for electrical noise of circuit in INPUT & OUTPUT SPEED SENSOR or Replace INPUT & OUTPUT SPEED SENSOR. Repair as necessary and go to "Verification of vehicle repair" procedure.
COMPONENT INSPECTION
1. Connect oil pressure gauge to "R/C(rear clutch)" port.
2. Engine "ON".
3. Drive a car at gear position 1 in "D RANGE".
4. Compare actual value to specifications.
Specification: Shown below
5. Is oil pressure value within specification?
YES
^ Repair AUTO TRANSAXLE(Clutch or brake) as necessary and go to "Verification of vehicle repair" procedure.
NO
^ Replace AUTO TRANSAXLE (BODY CONTROL VALVE faulty) as necessary and go to "Verification of vehicle repair" procedure.
VERIFICATION OF VEHICLE REPAIR
After a repair, it is essential to verify that the fault has been corrected.
1. Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode.
2. Using a Scantool, clear DTC.
3. Operate the vehicle within DTC enable conditions in general information.
4. Are any DTCs present?
YES
^ Go to the applicable troubleshooting procedure.
NO
^ System performing to specification at this time.