System Description
The A/T senses vehicle operating conditions through various sensors or signals. It always controls the optimum shift position and reduces shifting and lock-up shocks.
Component Description
| Name | Function |
|---|---|
| TCM | " DESCRIPTION " |
| PNP switch | " DESCRIPTION " |
| Vehicle speed sensor A/T (Revolution sensor) | " DESCRIPTION " |
| Turbine revolution sensor 1 | " DESCRIPTION " |
| Turbine revolution sensor 2 | |
| A/T fluid temperature sensor 1 | " DESCRIPTION " |
| A/T fluid temperature sensor 2 | |
| Input clutch solenoid valve | " DESCRIPTION " |
| Front brake solenoid valve | " DESCRIPTION " |
| Direct clutch solenoid valve | " DESCRIPTION " |
| High and low reverse clutch solenoid valve | " DESCRIPTION " |
| Low coast brake solenoid valve | " DESCRIPTION " |
| ATF pressure switch 2 (LC/B) | Detects any malfunction in the low coast brake hydraulic pressure. When it detects any malfunction, it puts the system into fail-safe mode. |
| Torque converter regulator valve | In order to prevent the pressure supplied to the torque converter from being excessive, the line pressure is adjusted to the optimum pressure (torque converter operating pressure). |
| Pressure regulator valve Pressure regulator plug Pressure regulator sleeve | Adjusts the oil discharged from the oil pump to the optimum pressure (line pressure) for the driving state. |
| Front brake control valve | When the front brake is coupled, adjusts the line pressure to the optimum pressure (front brake pressure) and supplies it to the front brake. (In 1st, 2nd, 3rd, and 5th gears, adjusts the clutch pressure.) |
| Accumulator control valve | Adjusts the pressure (accumulator control pressure) acting on the accumulator piston and low coast reducing valve to the pressure appropriate to the driving state. |
| Pilot valve A | Adjusts the line pressure and produces the constant pressure (pilot pressure) required for line pressure control, shift change control, and lock-up control. |
| Pilot valve B | Adjusts the line pressure and produces the constant pressure (pilot pressure) required for shift change control. |
| Low coast brake switching valve | During engine braking, supplies the line pressure to the low coast brake reducing valve. |
| Low coast brake reducing valve | When the low coast brake is coupled, adjusts the line pressure to the optimum pressure (low coast brake pressure) and supplies it to the low coast brake. |
| N-R accumulator | Produces the stabilizing pressure for when N-R is selected. |
| Direct clutch piston switching valve | Operates in 4th gear and switches the direct clutch coupling capacity. |
| High and low reverse clutch control valve | When the high and low reverse clutch is coupled, adjusts the line pressure to the optimum pressure (high and low reverse clutch pressure) and supplies it to the high and low reverse clutch. (In 1st, 3rd, 4th and 5th gears, adjusts the clutch pressure.) |
| Input clutch control valve | When the input clutch is coupled, adjusts the line pressure to the optimum pressure (input clutch pressure) and supplies it to the input clutch. (In 4th and 5th gears, adjusts the clutch pressure.) |
| Direct clutch control valve | When the direct clutch is coupled, adjusts the line pressure to the optimum pressure (direct clutch pressure) and supplies it to the direct clutch. (In 2nd, 3rd, and 4th gears, adjusts the clutch pressure.) |
| TCC control valve TCC control plug TCC control sleeve | Switches the lock-up to operating or released. Also, by performing the lock-up operation transiently, lock-up smoothly. |
| Torque converter lubrication valve | Operates during lock-up to switch the torque converter, cooling, and lubrication system oil passage. |
| Cool by-pass valve | Allows excess oil to bypass cooler circuit without being fed into it. |
| Line pressure relief valve | Discharges excess oil from line pressure circuit. |
| N-D accumulator | Produces the stabilizing pressure for when N-D is selected. |
| Manual valve | Transmits line pressure to each circuit according to the select position. The circuits to which the line pressure is not transmitted drain. |
| Accelerator pedal position sensor | " DESCRIPTION " |
| Throttle position sensor | |
| Manual mode switch | " DESCRIPTION " |
| Starter relay | " DESCRIPTION " |
COMPONENT DESCRIPTION
Scheme 1
Scheme 2
Scheme 3
DESCRIPTION
With the use of 3 sets of planetary gears, A/T enables 5-speed transmission for forward and 1-speed transmission for backward, depending on the combination of 3 sets of multiple-disc clutches, 3 sets of multiple-disc brakes, a brake band, and 3 sets of one-way clutches.
Scheme 4
Scheme 5
| Name of the Part (Abbreviation) | Function |
|---|---|
| Front brake (FR/B) | Fastens the front sun gear. |
| Input clutch (I/C) | Connects the input shaft, the front internal gear and the mid internal gear. |
| Direct clutch (D/C) | Connects the rear carrier and the rear sun gear. |
| High and low reverse clutch (HLR/C) | Connects the mid sun gear and the rear sun gear. |
| Reverse brake (R/B) | Fastens the rear carrier. |
| Forward brake (Fwd/B) | Fastens the mid sun gear. |
| Low coast brake (LC/B) | Fastens the mid sun gear. |
| 1st one-way clutch (1st OWC) | Allows the rear sun gear to turn freely forward relative to the mid sun gear but fastens it for reverse rotation. |
| Forward one-way clutch (Fwd OWC) | Allows the mid sun gear to turn freely in the forward direction but fastens it for reverse rotation. |
| 3rd one-way clutch (3rd OWC) | Allows the front sun gear to turn freely in the forward direction but fastens it for reverse rotation. |
| Torque converter | Amplifies driving force the engine, and transmits it to transmission input shaft. |
| Oil pump | Driven by the engine, oil pump supplies oil to torque converter, control valve assembly, and each lubricating system. |
COMPONENT DESCRIPTION
The selector lever cannot be shifted from the "P" position unless the brake pedal is depressed while the ignition switch is ON.
The shift lock is unlocked by the shift lock unit that is activated when the ignition switch is ON and the stop lamp switch is turned ON (brake pedal is depressed).
Therefore, the shift lock unit receives no ON signal and the shift lock remains locked if the above conditions are not fulfilled. (However, a shift operation is allowed if the shift lock release button is pressed.)
SHIFT LOCK OPERATION AT "P" POSITION
When Brake Pedal Is Not Depressed (No Shift Operation Allowed) The shift lock solenoid (A) inside the shift lock unit is not energized if the brake pedal is not depressed while the ignition switch is ON. The lock plate (B) lowers according to the downward movement of the position pin (C) when the selector button (D) is pressed, and presses only slider B (E) into the shift lock unit. Slider A (F) located below the lock plate prevents the downward movement of the lock plate with the spring force. The selector lever cannot be shifted from the "P" position for this reason.
However, slider A is forcibly pressed into the shift lock unit, allowing the selector lever to shift if the shift lock release button is pressed.
Scheme 6
When Brake Pedal Is Depressed (Shift Operation Allowed)
The shift lock solenoid (A) inside the shift lock unit is energized and the relative positions of sliders A (B) and B (C) are maintained when the brake pedal is depressed while the ignition switch is ON.
The lock plate (D) lowers according to the downward movement of the position pin (E), thrusting away sliders A and B, when the selector button (F) is pressed.
The position pin lowers to the position that allows shift operation for this reason. As a result, the selector lever can be shifted out of the P position.
Scheme 7
OPERATION AT OTHER THAN "P" POSITION
The shift lock function will not operate at any position other than "P" because the lock plate (A) is only set for the "P" position. Accordingly, the selector lever can be shifted to any position regardless of the brake operation.
The position pin (B) enters the "P" position thrusting away the lock plate when the selector lever is shifted to the "P" position. Then, the shift mechanism is locked when the selector button (C) is released.
Scheme 8
| Component | Function | ||
|---|---|---|---|
| Control device assembly | Shift lock unit | Shift lock solenoid | Activated by the ignition switch and stop lamp signals, it holds the relative positions of sliders A and B. |
| Lock plate | The lock plate restricts the position pin stroke by selector button operation according to the shift lock unit status. | ||
| Shift lock release button | Pressing the shift lock release button cancels the shift lock forcibly. | ||
| Position pin | The position pin, linking with the selector button, restricts the selector lever movement. | ||
| Stop lamp switch | Depressing the brake pedal turns ON the stop lamp switch and energizes the shift lock relay. | ||
COMPONENT DESCRIPTION
The A/T system has two self-diagnostic systems.
The first is the emission-related on board diagnostic system (OBD-II) performed by the TCM in combination with the ECM. The malfunction is indicated by the MIL (malfunction indicator lamp) and is stored as a DTC in the ECM memory but not the TCM memory.
The second is the TCM original self-diagnosis indicated by the A/T CHECK indicator lamp. The malfunction is stored in the TCM memory. The detected items are overlapped with OBD-II self-diagnostic items. For detail, refer to " CONSULT-III FUNCTION (TRANSMISSION) ".
- The MIL is located on the combination meters.
Scheme 9
- The MIL will light up when the ignition switch is turned ON without the engine running. This is a bulb check. If the MIL does not light up, refer to " «COMPONENT FUNCTION CHECK»(ref-368796-S41947899712010081300000) ".
- When the engine is started, the MIL should go off. If the MIL remains on, the on board diagnostic system has detected engine system malfunction.
As a method for locating the suspected circuit, when the self-diagnostics start signal is input, the memory for the malfunction location is output and the A/T CHECK indicator lamp flashes to display the corresponding DTC.
Operation Procedure
- Start the engine with selector lever in "P" position. Warm engine to normal operating temperature.
- Turn ignition switch ON and OFF at least twice, then leave it in the OFF position.
- Wait 10 seconds.
- Turn ignition switch ON. (Do not start the engine.)
- Check A/T CHECK indicator lamp comes on for about 2 seconds. CAUTION: If A/T CHECK indicator lamp does not come on, refer to " «SYMPTOM TABLE»(ref-368808-S40264355392010081300000) ".
- Turn ignition switch OFF.
- Keep pressing shift lock release button.
- Shift the selector lever from "P" to "D" position.
- Release accelerator pedal. (Set the closed throttle position signal ON.)
- Depress brake pedal. (Stop lamp switch signal ON.)
- Turn ignition switch ON. (Do not start the engine.)
- Wait 3 seconds.
- Shift the selector lever to the manual shift gate side. (Manual mode signal ON.)
- Release brake pedal. (Stop lamp switch signal OFF.)
- Shift the selector lever to "D" position. (Manual mode signal OFF.)
- Depress brake pedal. (Stop lamp switch signal ON.)
- Release brake pedal. (Stop lamp switch signal OFF.)
- Depress accelerator pedal fully and release it.
- Check A/T CHECK indicator lamp. Refer to " «JUDGMENT SELF-DIAGNOSIS CODE»(ref-368808-S13654650222010081300000) ". CAUTION: If the system does not go into self-diagnosis, refer to " «SYMPTOM TABLE»(ref-368808-S40264355392010081300000) ".
- Touch "DTC & SRT confirmation" in "TRANSMISSION".
- Touch select item menu.
- Touch "START".
- Perform driving test according to "DTC CONFIRMATION PROCEDURE" in "COMPONENT DIAGNOSIS FOR DTC". When testing conditions are satisfied, CONSULT-III screen changes from "OUT OF CONDITION" to "TESTING".
- Stop the vehicle. If "NG" appears on the screen, malfunction may exit.
- Perform test drive to check gear shift feeling in accordance with instructions displayed.
- Touch "YES" or "NO".
- CONSULT-III procedure is ended. If "NG" appears on the screen, malfunction may exit.
CAN (Controller Area Network) is a serial communication line for real-time application. It is an on-vehicle multiplex communication line with high data communication speed and excellent malfunction detection ability. Many electronic control units are equipped onto a vehicle, and each control unit shares information and links with other control units during operation (not independently). In CAN communication, control units are connected with 2 communication lines (CAN-H line, CAN-L line) allowing a high rate of information transmission with less wiring. Each control unit transmits/receives data but selectively reads required data only.
TCM prohibits cranking other than at "P" or "N" position.
The TCM consists of a microcomputer and connectors for signal input and output and for power supply. The TCM controls the A/T.
- The park/neutral position (PNP) switch includes the transmission range switch.
- The transmission range switch detects the selector lever position and transmits a signal to the TCM.
The turbine revolution sensor detects input shaft RPM (revolutions per minute). It is located on the input side of the A/T. Monitors revolution of sensor 1 and sensor 2 for non-standard conditions.
The revolution sensor detects the revolution of the parking gear and emits a pulse signal. The pulse signal is transmitted to the TCM which converts it into vehicle speed.
The engine speed signal is transmitted from the ECM to the TCM with CAN communication line.
This malfunction is detected when the A/T does not shift into 1st gear position as instructed by TCM. This is not only caused by electrical malfunction (circuits open or shorted) but by mechanical malfunction such as control valve sticking, improper solenoid valve operation, etc.
This malfunction is detected when the A/T does not shift into 2nd gear position as instructed by TCM. This is not only caused by electrical malfunction (circuits open or shorted) but by mechanical malfunction such as control valve sticking, improper solenoid valve operation, etc.
This malfunction is detected when the A/T does not shift into 3rd gear position as instructed by TCM. This is not only caused by electrical malfunction (circuits open or shorted) but by mechanical malfunction such as control valve sticking, improper solenoid valve operation, etc.
This malfunction is detected when the A/T does not shift into 4th gear position as instructed by TCM. This is not only caused by electrical malfunction (circuits open or shorted) but by mechanical malfunction such as control valve sticking, improper solenoid valve operation, etc.
This malfunction is detected when the A/T does not shift into 5th gear position as instructed by TCM. This is not only caused by electrical malfunction (circuits open or shorted) but by mechanical malfunction such as control valve sticking, improper solenoid valve operation, etc.
- The torque converter clutch solenoid valve is activated, with the gear in D3, D4, D5, M3, M4 and M5 by the TCM in response to signals transmitted from the vehicle speed sensor and accelerator pedal position sensor (throttle position sensor). Torque converter clutch piston operation will then be controlled.
- Lock-up operation, however, is prohibited when A/T fluid temperature is too low.
- When the accelerator pedal is depressed (less than 1.0/8) in lock-up condition, the engine speed should not change abruptly. If there is a big jump in engine speed, there is no lock-up.
This malfunction is detected when the A/T does not shift into 5th gear position or the torque converter clutch does not lock-up as instructed by the TCM. This is not only caused by electrical malfunction (circuits open or shorted) but also by mechanical malfunction such as control valve sticking, improper solenoid valve operation, etc.
The line pressure solenoid valve regulates the oil pump discharge pressure to suit the driving condition in response to a signal transmitted from the TCM.
Electric throttle control actuator consists of throttle control motor, accelerator pedal position sensor, throttle position sensor, etc. The actuator transmits a signal to the ECM, and ECM transmits signals to TCM with CAN communication.
The A/T fluid temperature sensor detects the A/T fluid temperature and transmits a signal to the TCM.
The vehicle speed sensor MTR signal is transmitted from unified meter and A/C amp. to TCM by CAN communication line. The signal functions as an auxiliary device to the revolution sensor when it is malfunctioning. The TCM will then use the vehicle speed sensor MTR signal.
Fail-safe function to detect interlock conditions.
Fail-safe function to prevent sudden decrease in speed by engine brake other than at M1 position.
- The Input clutch solenoid valve is controlled by the TCM in response to signals transmitted from the PNP switch, vehicle speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will then be shifted to the optimum position.
- The Input clutch solenoid valve controls the input clutch control valve in response to a signal transmitted from the TCM.
- The front brake solenoid valve is controlled by the TCM in response to signals transmitted from the PNP switch, vehicle speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will then be shifted to the optimum position.
- The front brake solenoid valve controls the front brake control valve in response to a signal transmitted from the TCM.
- The direct clutch solenoid valve is controlled by the TCM in response to signals transmitted from the PNP switch, vehicle speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will then be shifted to the optimum position.
- The direct clutch solenoid valve controls the direct clutch control valve in response to a signal transmitted from the TCM.
- The high and low reverse clutch solenoid valve is controlled by the TCM in response to signals transmitted from the PNP switch, vehicle speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will then be shifted to the optimum position.
- The high and low reverse clutch solenoid valve controls the high and low reverse clutch control valve in response to a signal transmitted from the TCM.
- The low coast brake solenoid valve is turned ON or OFF by the TCM in response to signals transmitted from the PNP switch, vehicle speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will then be shifted to the optimum position.
- The low coast brake solenoid valve controls the low coast brake switching valve in response to a signal transmitted from the TCM.
- Low coast brake solenoid valve is turned ON or OFF by the TCM in response to signals transmitted from the PNP switch, vehicle speed sensor and accelerator pedal position sensor (throttle position sensor). Gears will then be shifted to the optimum position.
- This is not only caused by electrical malfunction (circuits open or shorted) but also by mechanical malfunction such as control valve sticking, improper solenoid valve operation.
Manual mode switch is installed in control device assembly. It transmits manual mode switch, shift up and shift down switch signals to unified meter and A/C amp. Then unified meter and A/C amp. transmits signals to TCM with CAN communication.
TCM transmits the switch signals to unified meter and A/C amp. by CAN communication line. Then manual mode switch position is indicated on the A/T indicator. For inspection, refer to SHIFT POSITION INDICATOR CIRCUIT .
Supply power to TCM.
TCM transmit the switch signals to unified meter and A/C amp. by CAN communication line. Then manual mode switch position is indicated on the shift position indicator.
Refer to " SYSTEM DESCRIPTION ".
Scheme 10
Scheme 11
Indicates selector lever position.
- The road test inspects overall performance of the A/T and analyzes possible malfunction causes.
- The road test is performed out in the following three stages.
- " «CHECK BEFORE ENGINE IS STARTED»(ref-368808-S29318364362010081300000) ".
- " «CHECK AT IDLE»(ref-368808-S15301359862010081300000) ".
- Cruise test " «CRUISE TEST - PART 1»(ref-368808-S33586452342010081300000) " " «CRUISE TEST - PART 2»(ref-368808-S03852554882010081300000) " " «CRUISE TEST - PART 3»(ref-368808-S42114583252010081300000) " CAUTION: Always drive vehicle at a safe speed. Check the test procedure and inspection items before beginning the road test. Test all inspection items until the symptom is uncovered. Diagnose NG items when all road tests are complete.