Automatic Transmission (Diagnostic Codes & Circuit Tests): Overview Lexus LX J200

DESCRIPTION

The Park/Neutral Position (PNP) switch detects the shift lever position and sends signals to the ECM.

MONITOR DESCRIPTION

This DTC indicates 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 the engine can be started only when the shift lever is in P or N.

The park/neutral position switch sends a signal to the ECM according to the shift lever 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 illuminate the MIL and store the DTC.

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

The ECM applies voltage to the temperature sensor through the ECM terminal THO1.

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.

Scheme 409

These DTCs indicate an open or short in the Automatic Transmission Fluid (ATF) temperature sensor circuit. The ATF temperature sensor converts the 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 sensor circuit. If the resistance value of the ATF temperature is below 79 ohms*1 or higher 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.

HINT

1. The ATF temperature can be checked on the Techstream display.
2. *1: 150°C (302°F) or higher is indicated regardless of the actual ATF temperature.
3. *2: -40°C (-40°F) is indicated regardless of the actual ATF temperature.

Refer to DTC P0710. Refer to DESCRIPTION .

This DTC indicates that there is a problem with the signal from the Automatic Transmission Fluid (ATF) temperature 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 open or short in the ATF temperature sensor circuit or a fault in 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, turns on the MIL and stores the DTC.

When the ATF temperature is 105°C (221°F) or more and engine coolant temperature reaches 60°C (140°F) after cold start, the ECM also determines this as a fault, turns on the MIL and stores the DTC.

This sensor detects the rotation speed of the turbine which shows the input revolution of the 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. As a result, the gears shift smoothly.

Scheme 410

Reference: Inspect using an oscilloscope.

Check the waveform of the ECM connector.

Standard

Scheme 411

This DTC indicates that a pulse is not output from the speed sensor NT (turbine (input) speed sensor) or is output only a little. The NT terminal of the ECM detects the pulse signal from the speed sensor NT (input RPM). The ECM outputs a gear shift 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 with the shift lever in D, if the input shaft revolution is less than 300 rpm*1 although the output shaft revolution is 1000 rpm or more*2, the ECM detects the trouble, illuminates the MIL and stores the DTC.

HINT

1. *1: Pulse is not output or is irregularly output.
2. *2: The vehicle speed is approximately 50 km/h (31 mph) or more.

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.

Reference: Inspect using an oscilloscope.

Check the waveform of the ECM connector.

Standard

Scheme 412

The output speed sensor SP2 monitors the output shaft speed. The ECM controls the gear shift 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 speed sensor SP2 even while the vehicle is moving, it will conclude that there is a malfunction of the output speed sensor SP2. The ECM will illuminate the MIL and store a DTC.

The purpose of this circuit is to prevent the engine from stalling while driving in the lock-up condition when the 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, 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) five times for 2 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 413

HINT

1. Gear positions in the event of a shift solenoid valve mechanical problem: ECM gear shift command 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 the ON and OFF operation of the shift solenoid valves SL1, SL2, S1, S2, S3, S4 and SR, which are controlled by the ECM. If an open or short circuit occurs in the shift solenoid valves, the ECM controls the remaining normal shift solenoid valves to allow the vehicle to be operated safely. Refer to FAIL-SAFE CHART .

Reference: Inspect using an oscilloscope.

Check the waveform of the ECM connector.

Standard

Scheme 414

This DTC indicates an open or short in the shift solenoid valve SL1 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, illuminates the MIL and stores the DTC. Also, 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 open or short circuited solenoid.

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 that 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 with the shift solenoid valves, valve body or automatic transmission (clutch, brake or gear, etc.).

HINT

1. Gear positions in the event of a shift solenoid valve mechanical problem: ECM gear shift command 1st 2nd 3rd 4th 5th 6th *1: Actual gear position under shift solenoid valve S1 stuck ON malfunction 2nd 2nd 3rd 4th 5th 6th *2: Actual gear position under shift solenoid valve S1 stuck OFF malfunction 1st 1st 3rd 4th 5th 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. Gear position under normal conditions 1st 2nd 3rd 4th 5th 6th *1: Actual gear position under fail-safe mode when shift solenoid valve S1 stuck ON malfunction 2nd 2nd 3rd 4th 5th 6th *2: Actual gear position under fail-safe mode when shift solenoid valve 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 with the shift solenoid valves, valve body or automatic transmission (clutch, brake, gear, etc.).

HINT

Gear positions in the event of a shift solenoid valve mechanical problem

This DTC indicates a 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 with the shift solenoid valves, valve body or automatic transmission (clutch, brake or gear, etc.).

HINT

1. Gear positions in the event of a shift solenoid valve mechanical problem: ECM gear shift command 1st 2nd 3rd 4th 5th 6th *1: Actual gear position under shift solenoid valve S3 stuck ON malfunction 1st 2nd 3rd 3rd N* N* *2: Actual gear position under shift solenoid valve S3 stuck OFF malfunction 3rd 4th 4th 4th 5th 6th 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 shift solenoid valve S3 stuck ON malfunction 1st 2nd 3rd 3rd 3rd 3rd *2: Actual gear position under fail-safe mode when shift solenoid valve 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 with the shift solenoid valves, valve body or automatic transmission (clutch, brake or gear, etc.).

HINT

1. Gear positions in the event of a shift solenoid valve mechanical problem: ECM gear shift command 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 the ON and OFF operation of the shift solenoid valves SL1, SL2, S1, S2, S3, S4 and SR, which are controlled by the ECM. If an open or short circuit occurs in the shift solenoid valves, the ECM controls the remaining normal shift solenoid valves to allow the vehicle to be operated safely. Refer to FAIL-SAFE CHART .

Reference: Inspect using an oscilloscope.

Check the waveform of the ECM connector.

Standard

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, illuminates the MIL and stores the DTC. Also, the ECM performs the fail-safe function and turns the other normally functioning shift solenoid valves ON/OFF. In case of an open or short circuit, the ECM stops sending current to the open or short circuited solenoid.

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. When shifting to 2nd and 4th gears is impossible, or when the ECM directs the transmission to switch to 5th and 6th gear and the engine overruns (clutch slips), this DTC is stored.

Scheme 415

HINT

1. Gear positions in the event of a shift solenoid valve mechanical problem: ECM gear shift command 1st 2nd 3rd 4th 5th 6th Actual gear position under malfunction 1st 1st 3rd 3rd N* 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. Gear position under normal conditions 1st 2nd 3rd 4th 5th 6th Actual gear position under fail-safe mode 1st* 1st* 3rd 3rd 3rd 3rd 1st*: 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 with the shift solenoids, valve body, 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 detects the signal indicating that the transfer is in neutral.

This DTC indicates that the signal indicating that the transfer is in neutral remains on.

The ECM detects whether or not the transfer is in neutral by monitoring the signal from the transfer shift actuator assembly.

If the ECM detects that the transfer is in neutral under the following conditions, the ECM will conclude that there is a malfunction of the transfer shift actuator assembly, illuminate the MIL and store the DTC

1. The transfer shift actuator assembly indicates that the transfer is in neutral.
2. The transfer position switch is in the "H4" position.
3. The vehicle is being driven at 25 km/h (16 mph) or more.
4. The transfer neutral signal has been on for more than 30 seconds.

The shift 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 shift solenoid valve SLT to control the 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

Scheme 416

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 stores this DTC when the amount of heat absorption exceeds the specified value.

There are two causes of revolution difference.

1. When the shift solenoid valve SLT remains ON, oil pressure decreases, which causes the clutch engagement force to decrease.
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 are controlled by the ECM. If an open or short circuit occurs in any of the shift solenoid valves, the ECM controls the remaining normal shift solenoid valves to allow the vehicle to be operated safely. Also, the ECM stops sending current to the open or short circuited solenoid. 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, illuminates the MIL and stores the DTC. When the shift solenoid valve S1 is ON, if its 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 its resistance is 100 kohms or higher, 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 the ON and OFF operation of the shift solenoid valves SL1, SL2, S1, S2, S3, S4 and SR, which are controlled by the ECM. If an open or short circuit occurs in any of the shift solenoid valves, the ECM controls the remaining normal shift solenoid valves to allow the vehicle to be operated safely. Also, the ECM stops sending current to the open or short circuited solenoid. 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, illuminates the MIL and stores the DTC. When the shift solenoid valve S2 is ON, if its 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 its resistance is 100 kohms or higher, 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 the ON and OFF operation of the shift solenoid valves SL1, SL2, S1, S2, S3, S4 and SR, which are controlled by the ECM. If an open or short circuit occurs in any of the shift solenoid valves, the ECM controls the remaining normal shift solenoid valves to allow the vehicle to be operated safely. Also, the ECM stops sending current to the open or short circuited solenoid. 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, illuminates the MIL and stores the DTC. When the shift solenoid valve S3 is ON, if its 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 its resistance is 100 kohms or higher, 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 the ON and OFF operation of the shift solenoid valves SL1, SL2, S1, S2, S3, S4 and SR, which are controlled by the ECM. If an open or short circuit occurs in any of the shift solenoid valves, the ECM controls the remaining normal shift solenoid valves to allow the vehicle to be operated safely. Also, the ECM stops sending current to the open or short circuited solenoid. 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, illuminates the MIL and stores the DTC. When the shift solenoid valve S4 is ON, if its 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 its resistance is 100 kohms or higher, 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 the ON and OFF operation of the shift solenoid valves SL1, SL2, S1, S2, S3, S4 and SR, which are controlled by the ECM. If an open or short circuit occurs in any of the shift solenoid valves, the ECM controls the remaining normal shift solenoid valves to allow the vehicle to be operated safely. Also, the ECM stops sending current to the open or short circuited solenoid. 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, illuminates the MIL and stores the DTC. When the shift solenoid valve SR is ON, if its 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 its resistance is 100 kohms or higher, the ECM determines there is an open in the shift solenoid valve SR circuit. Refer to FAIL-SAFE CHART .

Refer to DTC P0894. Refer to DESCRIPTION .

Reference: Inspect using an oscilloscope.

Check the waveform of the ECM connector.

Standard

When an open or short in the shift 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 Automatic Transmission Fluid (ATF) temperature sensor is on the transmission, just in front of the oil cooler inlet pipeline.

If the ECM detects an abnormally high ATF temperature near this sensor, it illuminates the warning light.

HINT

1. The temperature of ATF easily rises when towing, climbing hills, in traffic, etc.
2. If the ATF temperature sensor becomes short-circuited, the signal that indicates that the ATF temperature is 150°C (302°F) or higher is input into the ECM.

Vehicle conditions when the sensor is normal and when the sensor is short-circuited are indicated in the table below.

HINT

*1: When ATF temperature is in the normal range, it decreases to below 135°C (275°F) within 5 minutes with the shift lever in P or N in an idling state.

*2: When ATF temperature is normal, transmission lock-up occurs in 5th or 6th gear with the shift lever in D or the S6 range, in 5th gear with the shift lever in the S5 range, and 4th gear with the shift lever in the S4 range.

The ATF temperature sensor converts the ATF temperature into 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 below 25 ohms*1 or higher than 156 kohms*2, the ECM interprets this as a fault in the ATF sensor or wiring. The ECM will illuminate the MIL and store the DTC.

HINT

1. *1: 150°C (302°F) or higher is indicated regardless of the actual ATF temperature.
2. *2: -40°C (-40°F) is indicated regardless of the actual ATF temperature.
3. The ATF temperature can be checked on the Techstream display.

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.

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

Scheme 417

Torque converter lock-up is controlled by the ECM based on the turbine (input) speed sensor NT, output speed sensor SP2, engine speed, 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 speed (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 illuminate the MIL and store the DTC.

Example

When one of the following conditions is met, the system determines that there is 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 ON. Engine speed is at least 70 rpm more 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 35 rpm.

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

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: Inspect using an oscilloscope.

Check the waveform of the ECM connector.

Standard

Scheme 418

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

The ECM detects the signal from the transfer L4 position switch.

This DTC indicates that the transfer L4 position switch remains on.

The ECM monitors the transfer-case L4 position switch to determine when the transfer-case L4 gears are engaged. If the transfer-case L4 gears remain engaged under the following conditions, the ECM will conclude that there is a malfunction of the L4 position switch, illuminate the MIL and store the DTC

1. L4 switch indicates that the L4 transfer-case gears are engaged.
2. The transfer-case shifter is in the "H4" position.
3. The transfer-case output shaft rpm is between 1000 and 3000 rpm.
4. The specified time period has elapsed.

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

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

Scheme 419

Scheme 420

Scheme 421

Scheme 422

1. INSPECT TRANSMISSION CONTROL SWITCH Disconnect the E52 transmission control switch connector. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition 3 (IG) - 7 (S) Shift lever in S, "+" or "-" Below 1 ohms 2 (SFTU) - 5 (E) Shift lever held in "+" (Up-shift) Below 1 ohms 1 (SFTD) - 5 (E) Shift lever held in "-" (Down-shift) Below 1 ohms 3 (IG) - 7 (S) Shift lever not in S, "+" or "-" 10 kohms or higher 2 (SFTU) - 5 (E) Shift lever in S 10 kohms or higher 1 (SFTD) - 5 (E) Shift lever in S 10 kohms or higher NG --> See step 5 OK: Go to next step
2. CHECK HARNESS AND CONNECTOR (TRANSMISSION CONTROL SWITCH - BATTERY, BODY GROUND) Disconnect the E52 transmission control switch connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition E52-3 (IG) - Body ground Engine switch on (IG) 11 to 14 V E52-3 (IG) - Body ground Engine switch off Below 1 V Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition E52-5 (E) - Body ground Always Below 1 ohms NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK: Go to next step
3. CHECK HARNESS AND CONNECTOR (TRANSMISSION CONTROL SWITCH - ECM) Disconnect the A38 ECM connector. Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Condition Specified Condition A38-25 (S) - Body ground Engine switch on (IG) Shift lever in S, "+" or "-" 11 to 14 V A38-25 (S) - Body ground Engine switch on (IG) Shift lever not in S, "+" or "-" Below 1 V Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition A38-38 (SFTU) - Body ground Engine switch off Shift lever held in "+" (Up-shift) Below 1 ohms A38-27 (SFTD) - Body ground Engine switch off Shift lever held in "-" (Down-shift) Below 1 ohms A38-38 (SFTU) - Body ground Engine switch off Shift lever in S 10 kohms or higher A38-27 (SFTD) - Body ground Engine switch off Shift lever in S 10 kohms or higher NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 4
4. PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to «PROBLEM SYMPTOMS TABLE»(ref-385197-S23047695242011021400000)
5. REPLACE TRANSMISSION CONTROL SWITCH (TRANSMISSION FLOOR SHIFT ASSEMBLY). Refer to «REMOVAL»(ref-385187-S32502138782011021400000)

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 No. 1 pattern select switch assembly, the park/neutral position switch and other various sensors, the ECM switches the shift solenoid valves on and off, and controls the transmission gear change and the lock-up clutch operation.

Scheme 423

When 2nd mode is selected with the No. 1 pattern select switch assembly, the ECM controls the shift solenoid valves and the transmission starts from 2nd gear.

The 2nd mode 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.

When the shift lever is in D, the transmission automatically shifts up through 3rd to 6th as usual.