P0731
DTC P0731 A/T 1ST GEAR FUNCTIONDescription
- This malfunction will not be detected while the A/T CHECK indicator lamp is indicating another self-diagnosis malfunction.
- This malfunction is detected when the A/T does not shift into first gear position as instructed by the TCM. This is not caused by electrical malfunction (circuits open or shorted) but by mechanical malfunction such as control valve sticking, improper solenoid valve operation, etc.
On Board Diagnosis Logic
- This is an OBD-II self-diagnostic item.
- Diagnostic trouble code "A/T 1ST OR FNCTN" with CONSULT-II or P0731 without CONSULT-II is detected when A/T cannot be shifted to the 1st gear position even if electrical circuit is good.
Possible Cause
- Shift solenoid valve A (Off stick.)
- 2nd brake
- 2nd coast brake
- One-way clutch No.1
- One-way clutch No.2
- Hydraulic control circuit
DTC Confirmation Procedure
CAUTION:
- Always drive vehicle at a safe speed.
- Be careful not to rev engine into the red zone on the tachometer.
NOTE: If "DTC Confirmation Procedure" has been previously performed, always turn ignition switch "OFF" and wait at least 10 seconds before performing the next test.
After the repair, perform the procedure to confirm the malfunction is eliminated.
WITH CONSULT-II
1. Start engine and select "A/T" with "DATA MONITOR" mode in CONSULT-II.
2. Make sure that ATF temperature is within the range.
FLUID TEMP: More than 20°C (68°F)
If out of range, drive the vehicle to warm up the fluid.
3. Accelerate vehicle to maintain the conditions for at least 12 consecutive seconds.
SLCT LVR POSI: "D" position
GEAR: 1st position [Vehicle speed and accelerator angle: 1st gear position retainable condition. (Refer to "VEHICLE SPEED WHEN SHIFTING GEARS - 9J500 MODELS".)
Driving location: Driving the vehicle uphill (increased engine load) will help maintain the driving conditions required for this test.
4. If DTC is detected, go to AT-499, "Diagnostic Procedure".
WITH GST
Follow the procedure "With CONSULT-II".
Wiring Diagram-AT-1STSIG
AT-1STSIG-01:
AT-1STSIG-01
Diagnostic Procedure
1. CHECK SHIFT SOLENOID VALVE A CIRCUIT
Perform "Diagnostic Procedure" for DTC P0750. Refer to AT-533, "Diagnostic Procedure". P0750
OK or NG
OK >> GO TO 2.
NG >> Repair or replace damaged parts.
2. CHECK MALFUNCTIONING ITEM
1. Control valve assembly. Refer to "Control Valve Assembly".
2. Disassembly A/T. Refer to "DISASSEMBLY".
3. Check the item:
- 2nd brake. Refer to "Oil Pump, 2nd Coast Brake & 2nd Brake".
- 2nd coast brake. Refer to "Oil Pump. 2nd Coast Brake & 2nd Brake", "One-Way Clutch Outer Race Sub Assembly & 2nd Coast Brake Hub & One-Way Clutch No.1".
- One-way clutch No. 1. Refer to "One-Way Clutch Outer Race Sub Assembly & 2nd Coast Brake Hub & One-Way Clutch No.1".
- One-way clutch No. 2. Refer to "DISASSEMBLY".
OK or NG
OK >> GO TO 3.
NG >> Repair or replace damaged parts.
3. CHECK DTC
Perform "DTC Confirmation Procedure". Refer to "DTC Confirmation Procedure".
OK or NG
OK >> INSPECTION END
NG >> Replace control valve assembly. Refer to "Control Valve Assembly".