Transmission Control System Electronic Controlled (ECT) - Diagnostics: Pre-Check

DIAGNOSIS SYSTEM

Description
1. When troubleshooting OBD II vehicles, the only difference from the usual troubleshooting procedure is that you need to connect an OBD II scan tool complying with SAE J1987 or a hand-held tester to the vehicle, and read off various data output from the vehicle's ECM.
  
  Fig 1: Identifying Malfunction Indicator Lamp (MIL)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
2. OBD II regulations require that the vehicle's on-board computer lights 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 SAE J2012 are recorded in the ECM memory.
  If the malfunction only occurs in 3 consecutive trips, the MIL goes off but the DTCs remain in the ECM memory.
3. To check the DTCs, connect OBD II scan tool or hand-held tester to the DLC3 of 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).
4. The DTCs include SAE controlled codes and Manufacturer controlled codes. SAE controlled codes must be set as prescribed by the SAE, while Manufacturer controlled codes can be set freely by a manufacturer within the prescribed limits. See DIAGNOSTIC TROUBLE CODE CHART ).
5. The diagnosis system operates in the normal mode during the 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 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).
6. 2 Trip Detection Logic: When a malfunction is first detected, the malfunction is temporarily stored in the ECM memory. If the same malfunction is detected again during the second test drive, this second detection causes the MIL to light up.

Inspect the DLC3.

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

Fig 2: Inspecting DLC3 Terminals

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

TESTER CONNECTION TEST

Tester Connection	Condition	Specified Condition
7 (Bus (+) Line) - 5 (Signal ground)	During communication	Pulse generation
4 (Chassis Ground) - Body	Always	1 Ω or less
5 (Signal Ground) - Body	Always	1 Ω or less
16 (B+) - Body	Always	9 - 14V

HINT:

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

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.

Normal Mode:
INSPECT DIAGNOSIS
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 TERMINALS OF ECU ).
  2. When the engine is started, the MIL should go off. If the lamp remains on, it means that the diagnosis system has detected a malfunction or abnormality in the system.
2. Check the DTC.
  NOTE: hand-held tester only:
  When the diagnostic 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. 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 the DLC3 at the lower of the instrument panel.
  3. Turn the ignition switch ON and press 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.
  5. See DIAGNOSTIC TROUBLE CODE CHART to confirm the details of the DTCs.
  NOTE: When simulating symptoms with an OBD II scan tool (excluding hand-held tester) to check the DTCs, use the normal mode. For codes on the DTCs chart subject to "2 trip detection logic", turn the ignition switch OFF after the symptom is simulated once. Then repeat the simulation process again. When the problem has been simulated twice, the MIL is indicated on the instrument panel and DTCs are recorded in the ECM.
Check Mode:
INSPECT DIAGNOSIS

HINT:

hand-held tester only:

Compared to the normal mode, the check mode has more sensitive ability to detect malfunctions. Furthermore, the same diagnostic items which are detected in the normal mode can also be detected in the check mode.
1. Check the DTC.
  1. Check the initial conditions.
    - Battery positive voltage 11 V or more
    - Throttle valve fully closed
    - Transaxle in P position A/C switched OFF
  2. Turn the ignition switch OFF.
  3. Prepare a hand-held tester.
  4. Connect the hand-held tester to the DLC3 at the lower of the instrument panel.
  5. Turn the ignition switch ON and push the hand-held tester ON.
    
    Fig 3: Checking MIL Flashes
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  6. Switch the hand-held tester from the normal mode to the check mode (check that the MIL flashes).
  7. Start the engine (MIL goes off 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.
    HINT:
    
    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, which erases all the DTCs, etc.
  10. After checking the DTC, inspect the applicable circuit.
2. Clear the DTC.
  1. When using OBD II scan tool or hand-held tester: When operating an OBD II scan tool (complying with SAE J1978) or hand-held tester to erase the codes, the DTCs and freeze frame data will be erased. (See the OBD II scan tool's instruction book for operating instructions.)
  2. When not using OBD II scan tool or hand-held tester: Remove the EFI fuse from engine room J/B for 10 seconds or more.
DATA LIST
HINT:

According to the DATA LIST displayed by the OBD II scan tool or hand-held tester, you can read the value of the switch, sensor, actuator and so on without parts removal. Reading the DATA LIST as a first step of troubleshooting is one of the methods to shorten the labor time.
1. Warm up the engine.
2. Turn the ignition switch OFF.
3. Connect the OBD II scan tool or hand-held tester to the DLC3.
4. Turn the ignition switch ON.
5. According to the display on tester, read the "DATA LIST".
  
  Fig 4: Data List
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
ACTIVE TEST
HINT:

Performing the ACTIVE TEST using the hand-held tester allows the relay, VSV, actuator and so on to operate without parts removal. Performing the ACTIVE TEST as a first step of troubleshooting is one of the methods to shorten the labor time.

It is possible to display the DATA LIST during the ACTIVE TEST.
1. Warm up the engine.
2. Turn the ignition switch OFF.
3. Connect the hand-held tester to the DLC3.
4. Turn the ignition switch ON.
5. According to the display on tester, perform the "ACTIVE TEST".
  
  Fig 5: Active Test Chart
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
PROBLEM SYMPTOM CONFIRMATION
1. Taking into consideration the results of the customer problem analysis, try to reproduce the symptoms of the trouble. If the problem is that the transaxle does not shift up, shift down, or the shift point is too high or too low conduct the following road test referring to the automatic shift schedule and simulate the problem symptoms.
ROAD TEST
NOTE: Perform the test at the ATF temperature 50-80°C (122-176°F) in the normal operation.
1. D position test
  Shift into the D position, depress the accelerator pedal fully and then check the following points:
  1. Check the up-shift operation.
    The up-shift operation, such as 1 to 2, 2 to 3 and 3 to O/D, is taken at the shift point shown in the automatic shift schedule (See SERVICE DATA ).
    
    HINT:
    - O/D Gear Up-shift Prohibition Control: 1. Coolant temp, is 60 °C (140 °F) or less. 2. If there is a difference of 10 km/h (6 mph) between the set cruise control speed and vehicle speed.
    - O/D 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 up-shift operation of 1 to 2, 2 to 3 and 3 to O/D.
  3. Check for abnormal noise and vibration.
    Run at the D position lock-up or O/D gear and check for abnormal noise and vibration.
    
    HINT:
    
    Check the cause of abnormal noise and vibration thoroughly, as it could be due to the loss of balance in the differential torque converter clutch, etc.
  4. Check the kick-down operation.
    While running in the D position, 2nd, 3rd and O/D gears, check that the possible kick-down vehicle speed limits of 2 to 1, 3 to 2 and O/D to 3 kick-downs conform to those indicated on the automatic shift schedule (See SERVICE DATA ).
  5. Check abnormal shock and slip at kick-down.
  6. Check the lock-up mechanism.
    - Drive in the D position, O/D gear, at steady speed (lock-up ON) of about 60 km/h (37 mph).
    - Depress the accelerator pedal lightly 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, depress the accelerator pedal fully and check the following points:
  1. Check up-shift operation.
    Check that the up-shift operation of is taken 1 to 2 up-shift takes place and that the shift point conforms to the automatic shift schedule (See SERVICE DATA ).
    
    HINT:
    
    There is no O/D up-shift and lock-up in the 2 position.
  2. Check the 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 noise during acceleration and deceleration, and for shock at up-shift and downshift.
3. L position test
  Shift into the L position, depress the accelerator pedal fully 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 the engine braking.
    While running in the L position, release the accelerator pedal and check the engine braking effect.
  3. Check for abnormal noise during acceleration and deceleration.
4. R position test
  Shift into the R position and depress the accelerator pedal fully and check for slipping.
  
  CAUTION: Before conducting this test, ensure that people and obstructions are kept away from the test area.
5. 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.
MECHANICAL SYSTEM TESTS
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 speeds in the D and R positions.
  NOTE:
  - Do the test at the normal operating fluid temperature of 50-80 °C (122-176 °F).
  - Do not continuously run this test longer than 5 seconds.
  - To ensure safety, conduct this test in a wide, clear and level area which provide 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.
  1. Chock the 4 wheels.
  2. Connect an OBD II scan tool or hand-held tester to the DLC3.
  3. Fully apply the parking brake.
  4. Keep your left foot pressed firmly on the brake pedal.
  5. Start the engine.
  6. Shift into the D position. Fully press down the accelerator pedal with your right foot. Quickly read the stall speed at this time.
    Stall speed: 2,550 +/- 150 RPM
  7. Do the same test in R position.
    Stall speed: 2,550 +/- 150 RPM
Evaluation:

Fig 6: Problem And Possible Cause Chart
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. 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 conditions of the O/D direct clutch, forward clutch, and 1st and reverse brake.
  NOTE:
  - Do the test at the normal operating fluid temperature of 50-80 °C (122-176 °F).
  - Be sure to allow 1 minute interval between the tests.
  - Take 3 measurements and take the average value.
  1. Connect an OBD II scan tool or hand-held tester to the DLC3.
  2. Fully apply the parking brake.
  3. Start the engine and check idle speed.
    Idle speed: 650 +/- 50 RPM (In N position and A/C OFF)
  4. Shift the shift lever from the N to D position. Using a stop watch, measure the time from when the lever is shifted until the shock is felt.
  5. Measure the time lag of N to R in the same way.
    Time lag:
    
    N to D Less than 1.2 seconds
    
    N to R Less than 1.5 seconds
  Evaluation (If N --> D time or N --> R time lag is longer than specified):
  
  Fig 7: Transmission Shift Lever Shifting Time Lag And Possible Cause
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HYDRAULIC TEST

Measure the line pressure.

NOTE:

Do the test at the normal operation fluid temperature the 50-80 °C (122-176 °F)
The line pressure 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.
Be careful to prevent SST's hose from interfering with the exhaust pipe.

Warm up the ATF.
Remove the test plug on the transaxle case front left side and connect SST.
SST 09992-00095 (09992-00231, 09992-00271)

Fig 8: Removing Test Plug On Transaxle Case Front Left Side And Connecting SST
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
Fully apply the parking brake and chock the 4 wheels.
Connect an OBD II scan tool or hand-held tester to the DLC3.
Start the engine and check the idling speed.
Keep your left foot pressed firmly on the brake pedal and shift into the D position.
Measure the line pressure when the engine is idling.
Depress the accelerator pedal all the way down. Quickly read the highest line pressure when the engine speed reaches the stall speed.

Do the test in the R position in the same way.

Specified line pressure:

LINE PRESSURE SPECIFICATION

Condition	D postion kpa (kgf/cm² , psi)	R postion kpa (kgf/cm² , psi)
Idling	382-422 (3.9-4.3,55-61)	647-760 (6.6-7.8,94-111)
Stall	713-844 (7.27-8.61,103-122)	1,2520-1,755 (15.5-17.9,220-254)

Evaluation:

Fig 9: Hydraulic Test Chart

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

MANUAL SHIFTING TEST

HINT:

With this test, it can be determined whether the trouble occurs in the electrical circuit or is a mechanical problem in the transaxle.

Disconnect the transmission wire connector.

Fig 10: Disconnecting Transmission Wire Connector
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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 change corresponds to the shift position.

MANUAL SHIFTING TEST

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

HINT:

If the L, 2 and D position gear positions are difficult to distinguish, do the following read test.

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

Connect the transmission wire connector.
Clear the DTC.