Automatic Transmission - Diagnostics: Pre-Check

1. Description
   • When troubleshooting the OBD II vehicles, the only difference from the usual troubleshooting procedure is that you connect the vehicle to the OBD II scan tool complying with the SAE J1987 or the hand-held tester, and read off the various data output from the vehicle's ECM.

     The OBD II regulations require that the vehicle's on-board computer should light up the Malfunction Indicator Lamp (MIL) on the instrument panel when the computer detects a malfunction in the computer itself or in the drive system components which affect the vehicle emissions. In addition to the MIL lighting up when a malfunction is detected, the applicable DTCs prescribed by the SAE J2012 are recorded in the ECM memory.

     If the malfunction only occurs in 3 trips, the MIL goes off but the DTCs remain recorded in the ECM memory.

     Fig 1: Identifying Malfunction

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

     The SAE controlled codes must be set as prescribed by the SAE, while the Manufacturer controlled codes can be set freely by a manufacturer within the prescribed limits (See the DTC chart on DIAGNOSTIC TROUBLE CODE CHART ).

   • The diagnosis system operates in the normal mode during the normal vehicle use, and also has the check mode for technicians to simulate malfunction symptoms and perform the troubleshooting. Most DTCs use the 2-trip detection logic* to prevent erroneous detection. By switching the ECM to the 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).
     Fig 2: Locating DLC3

     Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   • *: 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.

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

Fig 3: Identifying DLC3 Connector

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

• If the communication is normal when the tool is connected to another vehicle, inspect the DLC3 on the original vehicle.
• If the communication is still impossible 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.
      Fig 4: Identifying Malfunction Indicator Lamp (MIL)

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      NOTE: If the MIL does not light up, troubleshoot the combination meter (See COMBINATION METER ).
   2. When the engine is started, the MIL should go off. If the lamp remains on, the diagnosis system has detected a malfunction or an abnormality in the system.
2. Check the DTC.
   NOTE: Hand-held tester only: When the diagnosis system is switched from the normal mode to the check mode, all the DTCs and freeze frame data recorded in the normal mode will be erased. So before switching modes, always check the DTCs and freeze frame data, and note them down.
   1. Connect the scan tool (OBD II scan tool or hand-held tester) to the DLC3.
      Fig 5: Connecting Scan Tool To DLC3

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   2. Turn the ignition switch ON.
   3. Turn the scan tool switch ON.
   4. Use the scan tool to check the DTCs and freeze frame data and note them down (For operating instructions, see the scan tool instruction book).
   5. See DIAGNOSTIC TROUBLE CODE CHART  to confirm the details of the DTCs.

1. Check the DTC.
   1. Check the initial conditions.
      • Battery positive voltage 11 V or more.
      • Throttle valve fully closed.
      • Transaxle in P position.
      • Air conditioning switched OFF.
   2. Connect the scan tool (OBD II scan tool or hand-held tester) to the DLC3.
   3. Turn the ignition switch ON.
   4. Turn the scan tool switch ON.
   5. Switch the hand-held tester from the normal mode to the check mode (the MIL flashes).
      Fig 6: MIL Blinking Pattern

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   6. Start the engine (the MIL goes out after the engine starts).
   7. Simulate the conditions of the malfunction described by the customer.
      NOTE: Leave the ignition switch ON until you have checked the DTCs, etc.
   8. After simulating the malfunction conditions, use the scan tool diagnosis selector to check the DTCs and freeze frame data, etc.
      NOTE: Take care not to turn the ignition switch OFF, as turning it off switches the diagnosis system from the check mode to the normal mode, so all the DTCs, etc. are erased.
   9. After checking the DTC, inspect the applicable circuit.
2. Clear the DTC.

   The following operation will erase the DTC and freeze frame data. Operating the scan tool (OBD II scan tool or hand-held tester) to erase the codes (See the scan tool instruction book).

1. D position test:

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

   1. Check the up-shift operation.

      Check to see if the 1 --> 2, 2 --> 3 and 3 --> O/D up-shifts take place and if the shift points conform to the automatic shift schedule (See SERVICE DATA ).

      NOTE:

      • O/D Gear Up-shift Prohibition Control (1. Coolant temperature is 60°C (140°F) or less. 2. If there is a 10 km/h (6 mph) difference between the set cruise control speed and the actual vehicle speed.)
      • O/D Gear Lock-up Prohibition Control (1. Brake pedal is depressed. 2. Coolant temperature is 60°C (140°F) or less.)
   2. Check for shock and slip when shifting.

      Check for shock and slip at the 1 --> 2, 2 --> 3 and 3 --> O/D up-shifts.

   3. Check for abnormal noises and vibration.

      Drive the D position lock-up or the O/D gear and check for abnormal noises and vibration.

      NOTE: The cause of abnormal noises and vibration must be checked very thoroughly, as it could also cause loss of balance in the differential torque converter clutch, etc.
   4. Check the kick-down operation.

      While during in the D position, 2nd, 3rd and O/D gears, check to see if the 2 --> 1,3 --> 2 and O/D --> 3 kick-downs conform to the automatic shift schedule (See SERVICE DATA ).

   5. Check for abnormal shock and slip at the kick-downs.
   6. Check the lock-up mechanism.
      • Drive in the D position, O/D gear, at a steady speed (lock-up ON) of about 60 km/h (37 mph).
      • Lightly depress the accelerator pedal and check that the engine speed does not change abruptly.

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

2. 2 position test:

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

   1. Check the up-shift operation.

      Check to see if the 1 --> 2 up-shift takes place and if the shift point conforms to the automatic shift schedule (See SERVICE DATA ).

      NOTE: There is no O/D up-shift and lock-up in the 2 position.
   2. Check the engine braking.

      While driving in the 2 position, 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 the up-shift and the down-shift.
3. 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 driving in the L position, check that there is no up-shift to the 2nd gear.

   2. Check the engine braking.

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

   3. Check for abnormal noises during acceleration and deceleration.

4. 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 is free from people and obstruction.
5. P position test:

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

1. Check the fluid level.
   NOTE:

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

     ATF temperature: 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.
   1. Park the vehicle on a level surface.
   2. With the engine idling and the brake pedal depressed, shift the shift lever into all positions from P to L and put it back to the 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 D-II or DEXRON®III (DEXRON®II) 

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

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

   Fig 7: Checking Fluid Level

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
3. Replace the ATF.
   1. Remove the drain plug and drain the fluid.
      Fig 8: Removing Drain Plug

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   2. Reinstall the drain plug securely.
   3. With the engine OFF, add new fluid through the oil filler pipe.
      Fig 9: Filling Fluid Through Filler Plug

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Fluid type: ATF D-II or DEXRON®III (DEXRON®II) 

      Capacity: 4.75 liters (5.0 US qts, 4.2 lmp. qts) 

   4. Start the engine and shift the shift lever into all positions from P to L position and then shift into the P position.
   5. With the engine idling, check the fluid level. Add fluid up to the COOL level on the dipstick.
   6. Check the fluid level 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 transaxle.

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

5. Inspect and adjust the throttle cable.
   1. Check that the accelerator pedal is fully released.
   2. Check that the inner cable is not slack.
   3. Measure the distance between the outer cable end and stopper on the cable.
      Fig 10: Measuring Distance Between Outer Cable End & Stopper

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard distance: 0-1 mm (0-0.04 in.) 

   If the distance is not within the standard value, adjust the cable by the adjusting nuts.

6. Inspect and adjust the shift lever position.

   When shifting the shift lever from the N position to the 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.

   1. Loosen the nut on the shift lever.
      Fig 11: Locating Nut

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   2. Push the control shaft lever fully downward.
   3. Return the control shaft lever the 2 notches to the N position.
   4. Set the shift lever to the N position.
   5. While holding the shift lever lightly toward the R position, tighten the shift lever nut.
      Fig 12: Tightening Shift Lever Nut

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Torque: 13 N.m (130 kgf.cm, 9 ft.lbf) 

   6. Start engine, and make sure that the vehicle moves forward when the lever is shifted from the N to D position and that the vehicle is reversed when the shift lever is shifted to the R position

7. Inspect and adjust the park/neutral position.
   Fig 13: Inspect Park/Neutral Position

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Check that the engine can be started with the shift lever only in the N or P position, but not in the other positions.

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

   1. Loosen the park/neutral position switch bolt and set the shift lever to the N position.
   2. Align the groove with the neutral basic line.
   3. Tighten the bolt at the position.

   Torque: 5.4 N.m (55 kgf.cm, 48 in.lbf) 

   For continuity inspection of the park/neutral position switch (See CIRCUIT DESCRIPTION ).

8. Check the idle speed.

   Idle speed: 700 +/- 50 rpm 

   (In the N position and the air conditioner is OFF) 

1. Measure the stall speed.

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

   NOTE:

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

   Stall speed: 2,350-2,800 rpm 

   Evaluation: 

   Fig 14: AT Problem & Possible Cause Table (1 Of 2)

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Measure the time lag.

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

1. Connect the OBD II scan tool or the hand-held tester to the DLC3.
2. Fully apply the parking brake.
3. Start the engine and check the idle speed.

   Idle speed: 700 +/- 50 rpm (In the N position and the air conditioner is OFF) 

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

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

5. In the same manner, measure the time lag at N --> R.

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

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

Fig 15: AT Problem & Possible Cause Table (2 Of 2)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

Measure the line pressure.

1. Warm up the ATF.
2. Remove the test plug on the front left side of the transaxle case and connect the SST (See HYDRAULIC TEST for the location to connect SST).

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

3. Fully apply the parking brake and check the 4 wheels.
4. Connect the OBD II scan tool or the hand-held tester to the DLC3.
5. Start the engine and check the idling speed.
6. Keep your left foot pressing firmly the brake pedal and shift into the D position.
7. Measure the line pressure when the engine is idling.
8. Depress the accelerator pedal all the way down. Quickly read the highest line pressure when the engine speed reaches the stall speed.
9. In the same manner, conduct the test in the R position.

Specified line pressure: 

If the measured pressure is not up to the specified value, recheck the throttle cable adjustment and retest.

Evaluation 

Fig 16: AT Problem & Possible Cause Table

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

1. Disconnect the solenoid wire.
Fig 17: Locating Solenoid Wire
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. Inspect the manual driving operation.

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

   While driving, shift through the L, 2 and D positions.

   Check that the gear changes, corresponding to the shift position.

   SHIFT POSITION GEAR POSITION
   
   

   Shift Position	Gear Position
   D	O/D
   2	O/D
   L	1st
   R	Reverse
   P	Pawl Lock

   NOTE:

   If the L, 2 and D positions and the gear positions are difficult to distinguish, conduct the above manual shifting test.

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

3. Connect the solenoid wire.
4. Clear the DTC.