Automatic Transmission (A760E) (Diagnostic Codes & Circuit Tests): Overview Lexus GS III facelift

DESCRIPTION

The speed sensor SP2 detects the rotation speed of the transmission output shaft and sends signals to the ECM. The ECM determines the vehicle speed based on these signals. An AC voltage is generated in the speed sensor SP2 coil as the parking gear mounted on the rear planetary gear assembly rotates, and this voltage is sent to the ECM. The parking gear on the rear planetary gear is used as the timing rotor for this sensor.

The gear shift point and lock-up timing are controlled by the ECM based on the signals from this vehicle speed sensor and the throttle position sensor signal.

Scheme 762

Reference (Using an oscilloscope)

Check the waveform between terminals SP2+ and SP2- of the ECM connector.

Scheme 763

Standard

Refer to the illustration.

MONITOR DESCRIPTION

The output speed sensor SP2 monitors the output shaft speed. The ECM controls the gearshift point and the lock up timing based on the signals from the output speed sensor SP2 and throttle position sensor.

If the ECM detects no signal from the output shaft speed sensor SP2 even while the vehicle is moving, it will conclude that is a malfunction of the output speed sensor SP2. The ECM will illuminate the MIL and set a DTC.

The park/neutral position switch detects the shift lever position and sends signals to the ECM.

These DTCs indicate a problem with the park/neutral position switch and the wire harness in the park/neutral position switch circuit.

The park/neutral position switch detects the shift lever position and sends a signal to the ECM.

For security, the park/neutral position switch detects the shift lever position so that engine can be started only when the shift lever is in the P or N position.

The park/neutral position switch sends a signal to the ECM according to the shift position (P, R, N, D, or S). The ECM determines that there is a problem with the switch or related parts if it receives more than 1 position signal simultaneously. The ECM will turn on the MIL and store the DTC.

Refer to DESCRIPTION .

This DTC indicates that there is a problem with output from the automatic transmission fluid (ATF) temperature sensor (TFT sensor) and that the sensor itself is defective. The ATF temperature sensor converts the ATF temperature to an electrical resistance value. Based on the resistance, the ECM determines the ATF temperature and detects an opens or shorts in the ATF temperature circuit or a fault of the ATF temperature sensor.

After running the vehicle for a certain period, the ATF temperature should increase. If the ATF temperature is below 20°C (68°F) after running the vehicle for a certain period, the ECM interprets this as a fault, and turns on the MIL.

The ATF (Automatic Transmission Fluid) temperature sensor converts the fluid temperature into a resistance value which is input into the ECM.

Scheme 764

The ECM applies a voltage to the temperature sensor through ECM terminal OIL.

The sensor resistance changes with the transmission fluid temperature. As the temperature becomes higher, the sensor resistance decreases.

One terminal of the sensor is grounded so that the sensor resistance decreases and the voltage goes down as the temperature becomes higher.

The ECM calculates the fluid temperature based on the voltage signal.

These DTCs indicate an open or short in the automatic transmission fluid (ATF) temperature sensor (TFT sensor) circuit. The automatic transmission fluid (ATF) temperature sensor converts ATF temperature to an electrical resistance value. Based on the resistance, the ECM determines the ATF temperature, and the ECM detects an open or short in the ATF temperature circuit. If the resistance value of the ATF temperature is less than 79 ohms *1 or more than 156 kohms *2 , the ECM interprets this as a fault in the ATF sensor or wiring. The ECM will turn on the MIL and store the DTC.

*1: 150°C (302°F) or more is indicated regardless of the actual ATF temperature.

*2: -40°C (-40°F) is indicated regardless of the actual ATF temperature.

HINT

The ATF temperature can be checked on the Techstream display.

This sensor detects the rotation speed of the turbine which shows the input revolution of transmission. By comparing the input turbine speed signal (NT) with the counter gear speed sensor signal (SP2), the ECM detects the shift timing of the gears and appropriately controls the engine torque and hydraulic pressure according to various conditions. Thus, providing smooth gear shift.

Scheme 765

Reference (Using an oscilloscope)

Check the waveform between the terminals NT+ and NT- of the ECM connector.

Scheme 766

Standard

Refer to the illustration.

This DTC indicates that pulse is not output from the speed sensor NT (Turbine (input) speed sensor) or is output only little. The NT terminal of the ECM detects the revolving signal from speed sensor (NT) (input RPM). The ECM outputs a gearshift signal comparing the input speed sensor (NT) with the output speed sensor (SP2).

While the vehicle is operating in the 4th, 5th or 6th gear position in the shift position of D, if the input shaft revolution is less than 300 rpm *1 although the output shaft revolution is 300 rpm or more *2 , the ECM detects the trouble, illuminates the MIL and stores the DTC.

*1: Pulse is not output or is irregularly output.

*2: The vehicle speed is approx. 50 km/h (31 mph) or more.

The purpose of this circuit is to prevent the engine from stalling while driving in lock-up condition when brakes are suddenly applied.

When the brake pedal is depressed, this switch sends a signal to the ECM. Then the ECM cancels the operation of the lock-up clutch while braking is in progress.

This DTC indicates that the stop light switch remains on. When the stop light switch remains ON during "stop and go" driving, the ECM interprets this as a fault in the stop light switch and the MIL comes on and the ECM stores the DTC. The vehicle must stop (less than 3 km/h (2 mph)) and go (30 km/h (19 mph) or more) ten times for two driving cycles in order to detect a malfunction.

The ECM uses signals from the output speed sensor SP2 and input speed sensor NT to detect the actual gear position (1st, 2nd, 3rd, 4th, 5th or 6th gear). Then the ECM compares the actual gear with the shift schedule in the ECM memory to detect mechanical problems of the shift solenoid valves, valve body or automatic transmission (clutch, brake or gear, etc.).

Scheme 767

HINT

1. Gear positions in the event of a solenoid valve mechanical problem: ECM command gearshift 1st 2nd 3rd 4th 5th 6th Actual gear position under malfunction 1st 2nd 3rd 4th 5th 4th
2. Gear position during fail-safe operation: If any malfunction is detected, the ECM changes into the fail-safe mode to shift into the gear positions as shown in the table below. Gear position under normal conditions 1st 2nd 3rd 4th 5th 6th Actual gear position under fail-safe mode 1st 2nd 3rd 3rd 3rd 3rd

The ECM commands gear shifts by turning the shift solenoid valves "ON/OFF" and switching oil pressure to the valves in the valve body.

The DTC indicates that the sequence valve is locked in the direction the spring stretches and that shifting to the 6th gear is impossible.

Shifting from 1st to 6th is performed in combination with "ON" and "OFF" operation of the shift solenoid valves SL1, SL2, S1, S2, S3, S4 and SR which is controlled by the ECM. If an open or short circuit occurs in one of the shift solenoid valves, the ECM controls the remaining normal shift solenoid valve to allow the vehicle to be operated smoothly. Refer to FAIL-SAFE CHART .

Reference (Using an oscilloscope)

Check the waveform between the terminals SL1+ and SL1- of the ECM connector

Scheme 768

Standard

Refer to the illustration.

This DTC indicates an open or short in the shift solenoid valve SL1 circuit. The ECM commands gearshift by turning the shift solenoid valves "ON/OFF". When there is an open or short circuit in any shift solenoid valve circuit, the ECM detects the problem and illuminates the MIL and stores the DTC. And the ECM performs the fail-safe function and turns the other normal shift solenoid valves "ON/OFF". (In case of an open or short circuit, the ECM stops sending current to the circuit.)

While driving and shifting between 4th and 5th gears, if the ECM detects an open or short in the shift solenoid valve SL1 circuit, the ECM determines there is a malfunction. Refer to FAIL-SAFE CHART .

The ECM uses signals from the output shaft speed sensor and input speed sensor to detect the actual gear position (1st, 2nd, 3rd, 4th, 5th or 6th gear).

Then the ECM compares the actual gear with the shift schedule in the ECM memory to detect mechanical problems of the shift solenoid valves, valve body or automatic transmission (clutch, brake or gear, etc.).

HINT

1. Gear positions in the event of a solenoid valve mechanical problem: ECM command gearshift 1st 2nd 3rd 4th 5th 6th *1: Actual gear position under S1 stuck ON malfunction 2nd 2nd 3rd 4th 5th 6th *2: Actual gear position under S1 stuck OFF malfunction 1st 1st 3rd 4th 5th N* *: Neutral
2. Gear position during fail-safe operation: If any malfunction is detected, the ECM changes into the fail-safe mode to shift into the gear positions as shown in the table below. Gear position under normal conditions 1st 2nd 3rd 4th 5th 6th *1: Actual gear position under fail safe mode when S1 stuck ON malfunction 2nd 2nd 3rd 4th 5th 6th *2: Actual gear position under fail safe mode when S1 stuck OFF malfunction 1st*3 1st*3 3rd 3rd 3rd 3rd *3: Under engine braking downshifting to 1st or 2nd gear is prohibited.

This DTC indicates "stuck ON malfunction" or "stuck OFF malfunction" of the shift solenoid valve S1.

The ECM commands gear shifts by turning the shift solenoid valves "ON/OFF". When the gear position commanded by the ECM and the actual gear position are not the same, the ECM illuminates the MIL and stores the DTC.

The ECM uses signals from the output shaft speed sensor and input speed sensor to detect the actual gear position (1st, 2nd, 3rd, 4th, 5th or 6th gear).

Then the ECM compares the actual gear with the shift schedule in the ECM memory to detect mechanical problems of the shift solenoid valves, valve body or automatic transmission (clutch, brake or gear, etc.).

HINT

1. Gear positions in the event of a solenoid valve mechanical problem: ECM command gearshift 1st 2nd 3rd 4th 5th 6th *1: Actual gear position under S2 stuck ON malfunction ↑ ↑ 2nd ↑ 6th ↑ *2: Actual gear position under S2 stuck OFF malfunction 3rd 3rd 3rd ↑ 5th 5th

This DTC indicates "stuck ON malfunction" or "stuck OFF malfunction" of the shift solenoid valve S2.

The ECM commands gear shifts by turning the shift solenoid valves "ON/OFF". When the gear position commanded by the ECM and the actual gear position are not the same, the ECM illuminates the MIL and stores the DTC.

The ECM uses signals from the output shaft speed sensor and input speed sensor to detect the actual gear position (1st, 2nd, 3rd, 4th, 5th or 6th gear).

Then the ECM compares the actual gear with the shift schedule in the ECM memory to detect mechanical problems of the shift solenoid valves, valve body or automatic transmission (clutch, brake or gear, etc.).

HINT

1. Gear positions in the event of a solenoid valve mechanical problem: ECM command gearshift 1st 2nd 3rd 4th 5th 6th *1: Actual gear position under S3 stuck ON malfunction 1st 2nd 3rd 3rd N* N* *2: Actual gear position under S3 stuck OFF malfunction 3rd 4th 4th 4th 5th 6th *: Neutral
2. Gear position during fail-safe operation: If any malfunction is detected, the ECM changes into the fail-safe mode to shift into the gear positions as shown in the table below. Gear position under normal conditions 1st 2nd 3rd 4th 5th 6th3rd *1: Actual gear position under fail safe mode when S3 stuck ON malfunction 1st 2nd 3rd 3rd 3rd 3rd *2: Actual gear position under fail safe mode when S3 stuck OFF malfunction 3rd 4th 4th 4th 5th 6th

This DTC indicates "stuck ON malfunction" or "stuck OFF malfunction" of the shift solenoid valve S3.

The ECM commands gear shifts by turning the shift solenoid valves "ON/OFF". When the gear position commanded by the ECM and the actual gear position are not same, the ECM illuminates the MIL and stores the DTC.

The ECM uses signals from the output shaft speed sensor and input speed sensor to detect the actual gear position (1st, 2nd, 3rd, 4th, 5th or 6th gear).

Then the ECM compares the actual gear with the shift schedule in the ECM memory to detect mechanical problems of the shift solenoid valves, valve body or automatic transmission (clutch, brake or gear, etc.).

HINT

1. Gear positions in the event of a solenoid valve mechanical problem: ECM command gearshift 1st 2nd 3rd 4th 5th 6th *: Actual gear position under malfunction 1st 2nd 3rd 4th 4th 4th
2. Gear position during fail-safe operation: If any malfunction is detected, the ECM changes into the fail-safe mode to shift into the gear positions as shown in the table below. Gear position under normal conditions 1st 2nd 3rd 4th 5th 6th *: Actual gear position under fail-safe mode 1st 2nd 3rd 3rd 3rd 3rd

This DTC indicates "stuck OFF malfunction" of the shift solenoid valve S4, "stuck ON malfunction" of the shift solenoid valve SL2, or brake control valve malfunction. The ECM commands gear shifts by turning the shift solenoid valves "ON/OFF". When the gear position commanded by the ECM and the actual gear position are not same, the ECM illuminates the MIL and stores the DTC.

Shifting from 1st to 6th is performed in combination with "ON" and "OFF" operation of the shift solenoid valves SL1, SL2, S1, S2, S3, S4 and SR which is controlled by the ECM. If an open or short circuit occurs in one of the shift solenoid valves, the ECM controls the remaining normal shift solenoid valve to allow the vehicle to be operated smoothly. Refer to FAIL-SAFE CHART .

Reference (Using an oscilloscope)

Check the waveform between the terminals SL2+ and SL2- of the ECM connector

Standard

Refer to the illustration.

This DTC indicates an open or short in the shift solenoid valve SL2 circuit. The ECM commands gear shifts by turning the shift solenoid valves "ON/OFF". When there is an open or short circuit in any shift solenoid valve circuit, the ECM detects the problem and illuminates the MIL and stores the DTC. And the ECM performs the fail-safe function and turns the other shift solenoid valves in good condition "ON/OFF". (In case of an open or short circuit, the ECM stops sending current to the circuit.)

While driving and shifting gears, if the ECM detects an open or short in the shift solenoid valve SL2 circuit, the ECM determines there is a malfunction. Refer to FAIL-SAFE CHART .

The 1-2 shift valve performs shifting to 1st gear and other gears.

Scheme 769

HINT

1. Gear positions in the event of a solenoid valve mechanical problem: ECM command gearshift 1st 2nd 3rd 4th 5th 6th Actual gear position under malfunction 1st 1st 3rd 3rd N* N* *: Neutral
2. Gear position during fail-safe operation: If any malfunction is detected, the ECM changes into the fail-safe mode to shift into the gear positions as shown in the table below.

*: Under engine braking, downshifting to 1st or 2nd gear is prohibited.

This DTC indicates that the 1-2 shift valve in the valve body is locked in the direction the spring compresses.

The ECM commands gear shifts by turning the shift solenoid valves "ON/OFF" and switching oil pressure to the valves in the valve body.

The ECM calculates the "actual" transmission gear by comparing the signals from the input speed sensor (NT) and the output speed sensor (SP2). The ECM can detect many mechanical problems in the shift solenoids, valve body, and the transmission clutches, brakes, and gears. If the ECM detects that the actual gear position and the commanded gear position are different, it will illuminate the MIL and store the DTC .

The ECM calculates the amount of heat absorbed by the friction material based on the difference in revolution (clutch slippage) between the turbine and output shaft. The ECM illuminates the MIL and outputs this DTC when the amount of heat absorption exceeds the specified value.

There are two reasons that make the revolution difference.

1. When the shift solenoid valve SLT remains on, oil pressure goes down and clutch engagement force decreases.
2. When the shift solenoid valve remains on or off, the gear position commanded by the ECM and the actual gear position are not the same.

Note. If you continue driving under these conditions, the clutch will burn out and the vehicle will no longer be drivable.

Shifting from 1st to 6th is performed in combination with "ON" and "OFF" operation of the shift solenoid valves SL1, SL2, S1, S2, S3, S4 and SR which is controlled by the ECM. If an open or short circuit occurs in one of the shift solenoid valves, the ECM controls the remaining normal shift solenoid valve to allow the vehicle to be operated smoothly. (In case of an open or short circuit, the ECM stops sending current to the circuit.) Fail safe function. Refer to FAIL-SAFE CHART .

These DTCs indicate an open or short in the shift solenoid valve S1 circuit. When there is an open or short circuit in any shift solenoid valve circuit, the ECM detects the problem and illuminates the MIL and stores the DTC. When the shift solenoid valve S1 is on, if resistance is 8 ohms or less, the ECM determines there is a short in the shift solenoid valve S1 circuit.

When the shift solenoid valve S1 is off, if resistance is 100 kohms or more, the ECM determines there is an open in the shift solenoid valve S1 circuit. Refer to FAIL-SAFE CHART .

Shifting from 1st to 6th is performed in combination with "ON" and "OFF" operation of the shift solenoid valves SL1, SL2, S1, S2, S3, S4 and SR which is controlled by the ECM. If an open or short circuit occurs in one of the shift solenoid valves, the ECM controls the remaining normal shift solenoid valve to allow the vehicle to be operated smoothly. (In case of an open or short circuit, the ECM stops sending current to the circuit.) Fail safe function, refer to FAIL-SAFE CHART .

These DTCs indicate an open or short in the shift solenoid valve S2 circuit. When there is an open or short circuit in any shift solenoid valve circuit, the ECM detects the problem and illuminates the MIL and stores the DTC. When the shift solenoid valve S2 is on, if resistance is 8 ohms or less, the ECM determines there is a short in the shift solenoid valve S2 circuit.

When the shift solenoid valve S2 is off, if resistance is 100 kohms or more, the ECM determines there is an open in the shift solenoid valve S2 circuit. Refer to FAIL-SAFE CHART .

Shifting from 1st to 6th is performed in combination with "ON" and "OFF" operation of the shift solenoid valves SL1, SL2, S1, S2, S3, S4 and SR which is controlled by the ECM. If an open or short circuit occurs in one of the shift solenoid valves, the ECM controls the remaining normal shift solenoid valve to allow the vehicle to be operated smoothly. (In case of an open or short circuit, the ECM stops sending current to the circuit.) Fail safe function, refer to FAIL-SAFE CHART .

These DTCs indicate an open or short in the shift solenoid valve S3 circuit. When there is an open or short circuit in any shift solenoid valve circuit, the ECM detects the problem and illuminates the MIL and stores the DTC. When the shift solenoid valve S3 is on, if resistance is 8 ohms or less, the ECM determines there is a short in the shift solenoid valve S3 circuit.

When the shift solenoid valve S3 is off, if resistance is 100 kohms or more, the ECM determines there is an open in the shift solenoid valve S3 circuit. Refer to FAIL-SAFE CHART .

Shifting from 1st to 6th is performed in combination with "ON" and "OFF" operation of the shift solenoid valves SL1, SL2, S1, S2, S3, S4 and SR which is controlled by the ECM. If an open or short circuit occurs in one of the shift solenoid valves, the ECM controls the remaining normal shift solenoid valve to allow the vehicle to be operated smoothly. (In case of an open or short circuit, the ECM stops sending current to the circuit.) Fail safe function, refer to FAIL-SAFE CHART .

These DTCs indicate an open or short in the shift solenoid valve S4 circuit. When there is an open or short circuit in any shift solenoid valve circuit, the ECM detects the problem and illuminates the MIL and stores the DTC. When the shift solenoid valve S4 is on, if resistance is 8 ohms or less, the ECM determines there is a short in the shift solenoid valve S4 circuit.

When the shift solenoid valve S4 is off, if resistance is 100 kohms or more, the ECM determines there is an open in the shift solenoid valve S4 circuit. Refer to FAIL-SAFE CHART .

Shifting from 1st to 6th is performed in combination with "ON" and "OFF" operation of the shift solenoid valves SL1, SL2, S1, S2, S3, S4 and SR which is controlled by the ECM. If an open or short circuit occurs in one of the shift solenoid valves, the ECM controls the remaining normal shift solenoid valve to allow the vehicle to be operated smoothly. (In case of an open or short circuit, the ECM stops sending current to the circuit.) Fail safe function, refer to FAIL-SAFE CHART .

These DTCs indicate an open or short in the shift solenoid valve SR circuit. When there is an open or short circuit in any shift solenoid valve circuit, the ECM detects the problem and illuminates the MIL and stores the DTC. When the shift solenoid valve SR is on, if resistance is 8 ohms or less, the ECM determines there is a short in the shift solenoid valve SR circuit.

When the shift solenoid valve SR is off, if resistance is 100 kohms or more, the ECM determines there is an open in the shift solenoid valve SR circuit. Refer to FAIL-SAFE CHART .

The linear solenoid valve (SLT) controls the transmission line pressure for smooth transmission operation based on signals from the throttle position sensor and the vehicle speed sensor. The ECM adjusts the duty ratio* of the SLT solenoid valve to control hydraulic line pressure coming from the primary regulator valve. Appropriate line pressure assures smooth shifting with varying engine outputs.

HINT

*: The duty ratio is the ratio of the current ON time (A) to the total of the current ON and OFF time (A + B).

Duty Ratio (%) = A / (A + B) x 100

Reference (Using an oscilloscope)

Check the waveform between the terminals SLT+ and SLT- of the ECM connector

Standard

Refer to the illustration.

When an open or short in the linear solenoid valve (SLT) circuit is detected, the ECM interprets this as a fault. The ECM will turn on the MIL and store the DTC.

The ECM uses the signals from the throttle position sensor, Air-flow meter, turbine (input) speed sensor, output speed sensor and crankshaft position sensor to monitor the engagement condition of the lock-up clutch.

Scheme 770

Then the ECM compares the engagement condition of the lock-up clutch with the lock-up schedule in the ECM memory to detect a mechanical problems of the shift solenoid valve SLU, valve body and torque converter clutch.

Torque converter lock-up is controlled by the ECM based on the turbine (input) speed sensor NT, output speed sensor SP2, engine rpm, engine load, engine temperature, vehicle speed, transmission temperature, and gear selection. The ECM determines the lock-up status of the torque converter by comparing the engine rpm (NE) to the input turbine rpm (NT). The ECM calculates the actual transmission gear by comparing input turbine rpm (NT) to output shaft rpm (SP2). When conditions are appropriate, the ECM requests "lock-up" by applying control voltage to the shift solenoid SLU. When the SLU is turned on, it applies pressure to the lock-up relay valve and locks the torque converter clutch.

If the ECM detects no lock-up after lock-up has been requested or if it detects lock-up when it is not requested, the ECM interprets this as a fault in the shift solenoid valve SLU or lock-up system performance.

The ECM will turn on the MIL and store the DTC.

Example

When any of the following is met, the system judges it as a malfunction.

1. There is a difference in rotation between the input side (engine speed) and output side (input turbine speed) of the torque converter when the ECM commands lock-up. (Engine speed is at least 70 rpm greater than input turbine speed.)
2. There is no difference in rotation between the input side (engine speed) and output side (input turbine speed) of the torque converter when the ECM commands lock-up off. (The difference between engine speed and input turbine speed is less than 20 rpm.)

The amount of current flow to the solenoid is controlled by the duty ratio* of the ECM output signal. The higher the duty ratio becomes, the higher the lock-up hydraulic pressure becomes during the lock-up operation.

Scheme 771

*: duty ratio

The duty ratio is the ratio of the period of continuity in one cycle. For example, if A is the period of continuity in one cycle, and B is the period of non-continuity, then Duty Ratio (%) = A/(A+B) x 100.

Reference (Using an oscilloscope)

Check the waveform between the terminals SLU+ and SLU- of the ECM connector

Standard

Refer to the illustration.

When an open or short in a shift solenoid valve (SLU) circuit is detected, the ECM determines there is a malfunction. The ECM will turn on the MIL and store this DTC.

The engine control unit and the transmission control unit are located inside the ECM. The engine control unit intercommunicates with the transmission control ECU through the Controller Area Network (CAN).

If there is a problem in this intercommunication, the ECM sets a DTC.

When moving the shift lever into the S position using the transmission control switch, it is possible to switch the shift range position between "1" (first range) and "6" (sixth range).

Shifting to "+" once raises one shift range position, and shifting to "-" lowers one shift range position.

Scheme 772

Scheme 773

Scheme 774

Scheme 775

Scheme 776

1. CHECK HARNESS AND CONNECTOR (BATTERY - TRANSMISSION CONTROL SWITCH) Disconnect the transmission control switch connector of the shift lock control unit assembly. Measure the voltage according to the value(s) in the table below. Voltage Switch Condition Tester Connection Specified Condition Engine switch on (IG) 3 - Body ground 10 to 14 V Engine switch off ↑ Below 1 V NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (TRANSMISSION CONTROL SWITCH - BODY GROUND) Measure the resistance according to the value(s) in the table below. Resistance Tester Connection Specified Condition 5 - Body ground Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. INSPECT TRANSMISSION CONTROL SWITCH Measure resistance between each terminal of shift lock control unit assembly when the shift lever is moved to each position. Resistance Shift Position Tester Connection Specified Condition S, "+" and "-" 3 - 7 Below 1 ohms Except S, "+" and "-" ↑ 10 kohms or higher Press continuously "+" (Up shift) 2 - 5 Below 1 ohms S ↑ 10 kohms or higher Press continuously "-" (Down shift) 1 - 5 Below 1 ohms S ↑ 10 kohms or higher NG --> REPLACE TRANSMISSION CONTROL SWITCH OK: Go to next step
4. CHECK HARNESS AND CONNECTOR (TRANSMISSION CONTROL SWITCH - ECM) Connect the transmission control switch connector of shift lock control unit assembly. Disconnect the ECM connector. Turn the engine switch on (IG), and measure the voltage according to the value(s) in the table below when the shift lever is moved to each position. Voltage Shift Position Tester Connection Specified Condition S, "+" and "-" A7 - 9 (S) - Body ground 10 to 14 V Except S, "+" and "-" ↑ Below 1 V Turn the engine switch off. Disconnect the ECM connector. Measure the resistance according to the value(s) in the table below when the shift lever is moved to each position. Resistance Shift Position Tester Connection Specified Condition Press continuously "+" (Up shift) A7 - 30 (SFTU) - Body ground Below 1 ohms S ↑ 10 kohms or higher Press continuously "-" (Down shift) A7 - 19 (SFTD) - Body ground Below 1 ohms S ↑ 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

The cowl side J/B ECU receives pattern select switch information, and sends it through the multiplex communication system and CAN system to the ECM.

ECT SNOW is the system that operates the throttle motor to control engine output to reduce skidding of the driving wheels, and guarantee takeoff acceleration, driving straightness and turning stability.

Scheme 777

HINT

(*) Pattern Select Switch (ECT SNOW Switch)

When the ECT SNOW switch is pushed, the switch contact is made and the ECT SNOW mode is selected.

To cancel the ECT SNOW mode, push the ECT SNOW switch once again.

The ECT SNOW mode is automatically canceled when the engine switch is turned "OFF".

Scheme 778

Scheme 779

Scheme 780

1. DRIVING TEST Start the engine. Turn the ECT SNOW switch "OFF" (Normal drive mode). Confirm vehicle response by driving from a parked position to fully depressing the accelerator pedal. Turn the ECT SNOW switch "ON" and perform the same check as above. Confirm that there is a difference between ECT SNOW switch "ON" and "OFF". HINT: Driving test should be done on a paved road (a nonskid road). Make sure not to use the TRAC system when testing a vehicle equipped with one. OK There is a difference in acceleration between "ON" and "OFF". NG --> See step 2 OK --> PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOM TABLE
2. CHECK HARNESS AND CONNECTOR (PATTERN SELECT SWITCH ASSEMBLY - BODY GROUND) Disconnect the connector of the pattern select switch. Measure the resistance according to the value(s) in the table below. Resistance Tester Connection Specified Condition 3 - Body ground Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. INSPECT PATTERN SELECT SWITCH ASSEMBLY Measure the resistance according to the value(s) in the table below. Resistance Switch Condition Tester Connection Specified Condition Press continuously Pattern select switch (SNOW) 1 - 3 Below 1 ohms Release Pattern select switch (SNOW) ↑ 10 kohms or higher NG --> REPLACE PATTERN SELECT SWITCH ASSEMBLY OK: Go to next step
4. CHECK HARNESS AND CONNECTOR Connect the connector of the pattern select switch. Disconnect the cowl side junction block RH (multiplex network body ECU) connector. Measure the resistance between terminal PWR of the cowl side junction block RH (multiplex network body ECU) and body ground. Resistance Switch Condition Tester Connection Specified Condition Press continuously Pattern select switch (SNOW) K68 - 17 (SNOW) - Body ground Below 1 ohms Release Pattern select switch (SNOW) ↑ 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOM TABLE

The cowl side J/B ECU receives pattern select switch information, and sends it through the multiplex communication system and CAN system to the ECM.

The ECM memory contains the programs for the NORMAL and POWER shift patterns and lock-up pattern.

By following the programs corresponding to the signals from the pattern select switch, the neutral start and other various sensors, the ECM switches the solenoid valves ON and OFF, and controls the transmission gear change and the lock-up clutch operation.

Scheme 781

Scheme 782

1. CHECK HARNESS AND CONNECTOR (PATTERN SELECT SWITCH ASSEMBLY - BODY GROUND) Disconnect the connector of the pattern select switch. Measure the resistance according to the value(s) in the table below. Resistance Tester Connection Specified Condition 3 - Body ground Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
2. INSPECT PATTERN SELECT SWITCH ASSEMBLY Measure the resistance according to the value(s) in the table below. Resistance Switch Condition Tester Connection Specified Condition Pattern select switch (PWR) 3 - 7 Below 1 ohms Pattern select switch (NORM) ↑ 10 kohms or higher NG --> REPLACE PATTERN SELECT SWITCH ASSEMBLY OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (PATTERN SELECT SWITCH ASSEMBLY - MULTIPLEX NETWORK BODY ECU) Connect the connector of the pattern select switch. Disconnect the cowl side junction block RH (multiplex network body ECU) connector. Measure the resistance between terminal PWR of the cowl side junction block RH (multiplex network body ECU) and body ground. Resistance Switch Condition Tester Connection Specified Condition Pattern select switch (PWR) K68 - 18 (PWR) - Body ground Below 1 ohms Pattern select switch (NORM) ↑ 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE