Automatic Transmission - Diagnosis: Pre-Check

1. Description
   • When troubleshooting vehicles with OBD II, the only difference from the usual troubleshooting procedure is that you connect an OBD II scan tool complying with SAE J1987 or hand-held tester to the vehicle, and read off various data output from the vehicle's ECM.
   • OBD II regulations require that the vehicle's onboard computer lights up the Malfunction Indicator Lamp (MIL) on the instrument panel when the computer detects a malfunction in the computer itself or in drive system components which affect vehicle emissions. In addition to the MIL lighting up when a malfunction is detected, the applicable DTCs prescribed by SAE J2012 are recorded in the ECM memory (See SELF-DIAGNOSTICS ).

     If the malfunction not occurs in 3-trips, the MIL goes off but the DTCs remain recorded in the ECM memory.

     Fig 1: Identifying Multifunction Indicator Lamp (MIL)

     Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   • To check the DTCs, connect an OBD II scan tool or hand-held tester to DLC3 on the vehicle. The OBD II scan tool or hand-held tester also enables you to erase the DTCs and check freeze frame data and various forms of engine data (For instruction book).
   • DTCs include SAE controlled codes and Manufacturer controlled codes.

     SAE controlled codes must be set as the codes prescribed by the SAE, while Manufacturer controlled codes can be set freely by the manufacturer within the prescribed limits (See DTC chart in SELF-DIAGNOSTICS ).

     Fig 2: Connecting Hand-Held Tester To DLC3

     Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   • The diagnosis system operates in normal mode during normal vehicle use, and also has a check mode for technicians to simulate malfunction symptoms and perform troubleshooting. Most DTCs use 2-trip detection logic (*) to prevent erroneous detection. By switching the ECM to check mode when troubleshooting, the technician can cause the MIL to light up for a malfunction that is only detected once or momentarily (Hand-held tester) (See PRE-CHECK ).
   • *2-trip detection logic:

     When a logic malfunction is first detected, the malfunction is temporarily stored in the ECM memory. If the same malfunction is detected again during the 2nd test drive, this 2nd detection causes the MIL to light up. The 2-trip repeats the same mode 2nd time (However, the IG switch must be turned OFF between the 1st trip and 2nd trip.).

2. Inspect the DLC3.

   The vehicle's ECM uses the ISO 9141-2 communication protocol. The terminal arrangement of DLC3 complies with SAE J1962 and matches the ISO 9141-2 format.

   Fig 3: Inspecting DLC3

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

If your display shows "UNABLE TO CONNECT TO VEHICLE" when you have connected the cable of OBD II scan tool or hand-held tester to DLC3, turned the ignition switch ON and operated the scan tool, there is a problem on the vehicle side or tool side.

• If communication is normal when the tool is connected to another vehicle, inspect DLC3 on the original vehicle.
• If communication is still not possible when the tool is connected to another vehicle, the problem is probably in the tool itself, so consult the Service Department listed in the tool's instruction manual.

1. Check the MIL
   1. The MIL comes on when the ignition switch is turned ON and the engine is not running.

      HINT:

      If the MIL does not light up, troubleshoot the combination meter (See PROBLEM SYMPTOMS TABLE ).

   2. When the engine is started, the MIL should go off. If the lamp remains on, the diagnosis system has detected a malfunction or abnormality in the system.
2. Check the DTC.
   Fig 4: Identifying Multifunction Indicator Lamp (MIL)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Prepare an OBD II scan tool (complying with SAE J1978) or hand-held tester.
2. Connect the OBD II scan tool or hand-held tester to DLC3 at the lower of the instrument panel.
3. Turn the ignition switch ON and turn the OBD II scan tool or hand-held tester switch ON.
4. Use the OBD II scan tool or hand-held tester to check the DTCs and freeze frame data and note them down (For operating instructions, see the OBD II scan tool's instruction book).
5. See DIAGNOSTIC TROUBLE CODE CHART  to confirm the details of the DTCs.
   Fig 5: Connecting Hand-Held Tester To DLC3

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

Hand-held tester only: Compared to the normal mode, the check mode has high sensing ability to detect malfunctions. Furthermore, the same diagnostic items which are detected in Normal mode can also be detected in Check mode.

1. Check the DTC.
   1. Check the initial conditions.
      • Battery positive voltage 11 V or more
      • Throttle valve fully closed
      • Transmission in P position
      • Air conditioning switched OFF
   2. Turn the ignition switch OFF.
   3. Prepare a hand-held tester.
   4. Connect the hand-held tester to DLC3 at the lower side of the instrument panel.
   5. Turn the ignition switch ON and switch the handheld tester ON.
      Fig 6: Connecting Hand-Held Tester To DLC3 At Lower Side Of Instrument Panel

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   6. Switch the hand-held tester from Normal mode to Check mode (Check that the MIL flashes).
   7. Start the engine (MIL goes out after the engine starts).
   8. Simulate the conditions of the malfunction described by the customer.
      NOTE: Leave the ignition switch ON until you have checked the DTCs, etc.
   9. After simulating the malfunction conditions, use the hand-held tester diagnosis selector to check the DTCs and freeze frame data, etc.
      Fig 7: Identifying Waveform

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      HINT:

      Be sure not to turn the ignition switch OFF, as turning it off switches the diagnosis system from Check mode to Normal mode, which erases all DTCs, etc.

   10. After checking the DTC, inspect the applicable circuit.
2. Clear the DTC.

   The following operation will erase the DTC and freeze frame data. Operate an OBD II scan tool (complying with SAE J1978) or hand-held tester to erase the codes (See the OBD II scan tool's instruction book for operating instructions).

1. D position test (NORM and PWR pattern):

   Shift into the D position and fully depress the accelerator pedal and check the following points.

   1. Check up-shift operation.

      Check that 1 --> 2, 2 --> 3, 3 --> 4 and 4 --> 5th up-shifts take place, and that the shift points conform to the automatic shift schedule (See AUTOMATIC TRANSMISSION (SERVICE SPECIFICATIONS) ).

      HINT:

      • 5th Gear Up-shift Prohibition Control (1. Coolant temp, is 55 °C (128 °F) or less. 2. Vehicle speed is 51 km/h (32 mph) or less.)
      • 5th Gear Lock-up Prohibition Control (1. Brake pedal is depressed. 2. Coolant temp, is 60 °C (140 °F) or less.)
   2. Check for shift shock and slip.

      Check for shock and slip at the 1 --> 2, 2 --> 3, 3 --> 4 and 4 --> 5th up-shifts.

   3. Check for abnormal noises and vibration.

      Drive in the D position lock-up or 5th gear and check for abnormal noises and vibration.

      HINT:

      The check for the cause of abnormal noises and vibration must be done very thoroughly as it could also be due to loss of balance in the differential, torque converter clutch, etc.

   4. Check kick-down operation.

      While running in the D position, 2nd, 3rd, 4th and 5th gears, check that the possible kick-down vehicle speed limits for 2 --> 1, 3 --> 2, 4 --> 3 and 5th --> 4 kick-downs conform to those indicated on the automatic shift schedule (See AUTOMATIC TRANSMISSION (SERVICE SPECIFICATIONS) ).

   5. Check abnormal shock and slip at kick-down.
   6. Check the lock-up mechanism.
      • Drive in D position 5th gear, at a steady speed (lock-up ON) of about 70 km/h (43 mph).
      • Lightly depress the accelerator pedal and check that the engine speed does not change abruptly.

        If there is a big jump in engine speed, there is no lock-up.

2. 4 position test:

   Shift into the 4 position and fully depress the accelerator pedal and check the following points.

   1. Check up-shift operation.

      Check that the 1 --> 2, 2 --> 3 and 3 --> 4 up-shift takes place and that the shift point conforms to the automatic shift schedule (See AUTOMATIC TRANSMISSION (SERVICE SPECIFICATIONS) ).

      HINT:

      There is no 5th up-shift in the 4 position.

   2. Check engine braking.

      While driving in the 4 position and 4th gear, release the accelerator pedal and check the engine braking effect.

   3. Check for abnormal noises during acceleration and deceleration, and for shock at up-shift and down-shift.
3. 3 position test:

   Shift into the 3 position and fully depress the accelerator pedal and check the following points.

   1. Check up-shift operation.

      Check that the 1 --> 2 and 2 --> 3 up-shift takes place and that the shift point conforms to the automatic shift schedule (See AUTOMATIC TRANSMISSION (SERVICE SPECIFICATIONS) ).

   2. Check engine braking.

      While running in the 3 position and 3rd gear, release the accelerator pedal and check the engine braking effect.

   3. Check for abnormal noises during acceleration and deceleration, and for shock at up-shift and down-shift.
4. 2 position test:

   Shift into the 2 position and fully depress the accelerator pedal and check the following points.

   1. Check up-shift operation.

      Check that the 1 --> 2 up-shift takes place and that the shift point conforms to the automatic shift schedule (See AUTOMATIC TRANSMISSION (SERVICE SPECIFICATIONS) ).

   2. Check engine braking.

      While running in the 2 position and 2nd gear, release the accelerator pedal and check the engine braking effect.

   3. Check for abnormal noises during acceleration and deceleration, and for shock at up-shift and down-shift.
5. L position test:

   Shift into the L position and fully depress the accelerator pedal and check the following points.

   1. Check no up-shift.

      While running in the L position, check that there is no up-shift to 2nd gear.

   2. Check engine braking.

      While running in the L position, release the accelerator pedal and check the engine braking effect.

   3. Check for abnormal noises during acceleration and deceleration.
6. R position test:

   Shift into the R position and fully depress the accelerator pedal and check for slipping.

   CAUTION: Before conducting this test ensure that the test area as free from people and obstruction.
7. P position test:

   Stop the vehicle on a grade (more than 5°) and after shifting into the P position, release the parking brake. Then, check that the parking lock pawl holds the vehicle in place.

You are able to set the A/T gear position as you like by operating each solenoid valve forcibly using OBD II scan tool or hand-held tester.

However, the condition that you can set the gear position differs depending on the setting gear position, so perform the ACTIVE TEST following conditions in the table below.

1. Check the fluid level.

   HINT:

   • Drive the vehicle so that the engine and transmission are at normal operating temperature.

     Fluid temp.: 70 - 80 °C (158 - 176 °F) 

   • Only use the COOL range on the dipstick as a rough reference when the fluid is replaced or the engine does not run.
     Fig 8: Identifying Brake Pedal

     Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   1. Park the vehicle on a level surface and set the parking brake.
   2. With the engine idling and the brake pedal depressed, shift the shift lever into all positions from P to L position and return to P position.
   3. Pull out the dipstick and wipe it clean.
   4. Push it back fully into the pipe.
   5. Pull it out and check that the fluid level is in the HOT range.

   If the level is not within the range, add new fluid.

   Fluid type: ATF TYPE T-IV 

   NOTE: Do not overfill.
2. Check the fluid condition.

   If the fluid smells burnt or is black, replace it.

   Fig 9: Checking Fluid Level

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Replace the ATF.
   1. Remove the drain plug and drain the fluid.
   2. Reinstall the drain plug securely.
   3. With the engine OFF add new fluid through the oil filler pipe.

      Fluid type: ATF TYPE T-IV 

      Capacity: 

      1.8 liters (1.9 US qts, 1.6 Imp. qts) 

   4. Start the engine and shift the shift lever into all positions from P to L position and then shift into P position.
   5. With the engine idling, check the fluid level. Add fluid up to the COOL level on the dipstick.
      Fig 10: Replacing ATF

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   6. Check the fluid level is at the normal operating temperature, 70 - 80 °C (158 - 176 °F), and add as necessary.
   NOTE: Do not overfill.
4. Check the fluid leaks.

   Check for leaks in the transmission.

   If there are leaks, it is necessary to repair or replace O-rings, FIPGs, oil seals, plugs or other parts.

   Fig 11: Checking Fluid Level

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
5. Inspect and adjust the shift lever position.

   When shifting the shift lever from the N position to other positions, check that the lever can be shifted smoothly and accurately to each position and that the position indicator is aligned with the correct position.

   If the indicator is not aligned with the correct position, carry out the following adjustment procedures.

   • Loosen the nut on the shift lever.
   • Push the control shaft fully rearward.
   • Return the control shaft lever 2 notches to N position.
   • Set the shift lever to N position.
   • While holding the shift lever lightly toward the R position side, tighten the shift lever nut.

   Torque: 13 N.m (130 kgf.cm, 10 ft.lbf) 

   • Start the engine and make sure that the vehicle moves forward when shifting the lever from the N to D position and reverses when shifting it to the R position.
     Fig 12: Adjusting Shift Lever Position

     Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
6. Inspect and adjust the park/neutral position switch.
   • Check that the engine can be started with the shift lever only in the N or P position, but not in other positions.

   If it is not as stated above, carry out the following adjustment procedures.

   • Loosen the park/neutral position switch bolt and set the shift lever to the N position.
   • Align the groove and neutral basic line.
   • Hold the switch in position and tighten the bolt.
     Fig 13: Identifying Park/Neutral Position Switch Components

     Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Torque: 13 N.m (130 kgf.cm, 10 ft.lbf) 

   • For continuity inspection of the park/neutral position switch, see DTC P0705 Transmission Range Sensor Circuit Malfunction (PRNDL Input) .
7. Check the idle speed.

   Idle speed (In H position and air conditioner OFF): 750 +/- 50 rpm 

1. Measure the stall speed.

   The object of this test is to check the overall performance of the transmission and engine by measuring the stall speeds in the D position.

   NOTE:

   • Do the test at normal operating fluid temperature 50 - 80 °C (122 - 176 °F). 
   • Do not continuously run this test for longer than 5 seconds. 
   • To ensure safety, conduct this test in a wide, clear level area which provides good traction. 
   • The stall test should always be carried out in pairs. One technician should observe the conditions of wheels or wheel stoppers outside the vehicle while the other is doing the test. 
   • Chock the 4 wheels.
   • Connect an OBD II scan tool or hand-held tester to DLC3.
   • Fully apply the parking brake.
   • Keep your left foot depressing firmly on the brake pedal.
   • Start the engine.
   • Shift into the D position. Press all the way down on the accelerator pedal with your right foot. Quickly read the stall speed at this time.

   Stall speed: 

   2,450 +/- 150 rpm (In D position) 

   Evaluation: 

   EVALUATION
   
   

   Problem	Possible cause
   (a)Stall speed low in D position	Engine output may be insufficient Stator one-way clutch is operating properly HINT: If the value is larger or smaller than the specified value by 600 rpm or more, the torque converter could be faulty.
   (b)Stall speed high in D position	Line pressure too low Forward clutch slipping No. 2 one-way clutch not operating properly O/D one-way clutch not operating properly

2. Measure the time lag.

   When the shift lever is shifted while the engine is idling, there will be a certain time lapse or lag before the shock can be felt. This is used for checking the condition of the O/D direct clutch, forward clutch, and 1st & reverse brake.

   NOTE:

   • Do the test at normal operating fluid temperature 50 - 80 °C (122 - 176 °F). 
   • Be sure to allow 1 minute interval between tests. 
   • Take 3 measurements and take the average value. 
   • Fully apply the parking brake.
   • Start the engine and check idle speed.

   Idle speed (In N position and air conditioner OFF): 

   750 +/- 50 rpm 

   • Shift the shift lever from N to D position. Using a stop watch, measure the time from when the lever is shifted until the shock is felt.

   Time lag: N --> D Less than 1.2 seconds 

   • In the same manner, measure the time lag for N --> R.

   Time lag: N --> R Less than 1.5 seconds 

   Evaluation (If N --> D time or N --> R time lag is longer than the specified): 

   EVALUATION
   
   

   Problem	Possible cause
   N --> D time lag is longer	Line pressure too low Forward clutch worn O/D one-way clutch not operating properly
   N --> R time lag is longer	pressure too low Direct clutch worn 1st & reverse brake worn O/D one-way clutch not operating properly

Measure the line pressure.

1. Warm up the ATR
2. Remove the test plug on the front left side of the transmission case and connect SST (See COMPONENTS for the location to connect SST).

   SST 09992-00095 (09992-00231, 09992-00271)

3. Fully apply the parking brake and chock the 4 wheels.
4. Start the engine and check idling speed.
5. Keep your left foot pressing firmly on the brake pedal and shift into D position.
6. Measure the line pressure when the engine is idling.
7. Depress the accelerator pedal all the way down. Quickly read the highest line pressure when engine speed reaches stall speed.
8. In the same manner, do the test in R position.

Specified line pressure: 

If the measured pressures are not up to the specified values, recheck the throttle cable adjustment and re-test.

Evaluation: 

HINT:

By this test, it can be determined whether the trouble is within the electrical circuit or is a mechanical problem in the transmission.

1. Disconnect the solenoid wire.
2. Inspect the manual driving operation.

   Check that the shift and gear positions correspond to the table below.

   While driving, shift through the L, 2, 3, 4 and D positions. Check that the gear change corresponds to the shift position.

   Fig 14: Inspecting Manual Driving Operation

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   SHIFT POSITION AND GEAR POSITION
   
   

   Shift Position	Gear Position
   D	5th
   4	5th
   3	4th
   2	3rd
   L	3rd
   R	Reverse
   P	Pawl Lock

   HINT:

   If the gear positions of the L, 2, 3, 4 and D are difficult to distinguish, do the above read test.

   If any abnormality is found in the above test, the problem is in the transmission itself.

3. Connect the solenoid wire.
4. Clear out the DTC (See PRE-CHECK ).