Automatic Transaxle (Diagnostics): Overview Subaru BRZ ZC

Description Of Functions

1. Diagnosis function The check engine warning light illuminates when a malfunction occurs in the AT system. CAUTION: The light goes off if the malfunction item returns to the normal state. However, diagnostic codes are recorded. Diagnostic results of malfunction occurrence are recorded in the transmission control computer. CAUTION: Do not disconnect the MAIN fuse, AT+B fuse, and battery terminal until the check finishes.
2. Fail-safe function When there is an open or short circuit in any solenoid valve system, only the mechanical hydraulic circuit operates and the manual shift control is initiated. (When open and short circuits occur, the transmission control computer stops continuity of all solenoid valves.)

Current Data Display & Save / System Operation Check Mode

1. Inspection with SSM3 (Current Data Display & Save) CAUTION: Subtle phenomena such as breathing and rough idling need to be totally judged based on all items in the computer data by using a method of comparing with an equivalent vehicle after collecting data under the same condition. Use SSM3 to display the [Current Data Display & Save] screen according to the screen display and check the computer data. SSM3 SCREEN: [TRANSMISSION CONTROL SYSTEM] -->[CURRENT DATA DISPLAY & SAVE] --> [NORMAL SAMPLING] Item name [Symbol] Description/display range Normal value Remarks [Coolant Temp.] Indicating engine coolant temperature/Display range: -40 to 140°C Gradually increasing: Cold start -->warmed up When abnormal, the THW voltage may be abnormal. 80 to 105°C: Warmed up When abnormal, the THW voltage may be abnormal. 215°C: When sensor is disconnected When abnormal, the THW voltage may be abnormal. 215°C or more: When sensor is shorted When abnormal, the THW voltage may be abnormal. [Engine Speed] Indicating engine speed/Display range: 0 to 16383.75 r/min 0 r/min: When engine is stopped (IG ON) When abnormal, there may be an NE signal malfunction. No significant fluctuation: When engine is running at a constant speed When abnormal, there may be an NE signal malfunction. [Vehicle Speed] Indicating vehicle speed/Display range: 0 to 255 km/h {158 MPH} 0 km/h {0 MPH}: When vehicle is parked When abnormal, there may be an SPD signal malfunction. No significant fluctuation: When driving at a constant speed When abnormal, there may be an SPD signal malfunction. [Time Since Engine Start] Indicating time elapsed after engine start (engine start -->IG OFF)/Display range: 0 to 65535 sec - - [Number of warm-ups] Indicating number of warming-ups after DG is cleared/Display range: 0 to 255 times - - [Meter since DTC cleared] Indicating travel distance after diagnostic codes cleared/Display range: 0 to 65535 km - - [Time since DTC cleared] Indicating time elapsed after diagnostic codes are cleared/Display range: 0 to 65535 min - - [Control module voltage] Indicating battery voltage/Display range: 0 to 65.535 V 11 to 14 V: During idling When abnormal, the BATT voltage may be abnormal. [MI(MIL)] Indicating TCM side MIL illumination indication status/Display range: OFF <---->ON OFF -->ON: Normal -->malfunction - [Number of Diagnostic Code(s):] Indicating trouble codes stored in TCM/Display range: 0 to 127 - - [Component monitoring(Supp)] Indicating component monitor test/Display range: without support <---->with support With support - [Fuel system monitoring(Supp)] Indicating fuel system monitor test/Display range: without support <---->with support Without support - [Misfire monitoring(Supp)] Indicating misfire monitor test/Display range: without support <---->with support Without support - [EGR system(Supp)] Indicating EGR system test/Display range: without support <---->with support Without support - [O2 Heater Diagnosis(Supp)] Indicating O2 sensor heater test/Display range: without support <---->with support Without support - [Oxygen sensor(Supp)] Indicating O2 sensor test/Display range: without support <---->with support Without support - [A/C system refrigerant(Supp)] Indicating refrigerant test on air conditioner system/Display range: without support <---->with support Without support - [Secondary air system(Supp)] Indicating secondary air system test/Display range: without support <---->with support Without support - [Evaporative purge system(Supp)] Indicating test on evaporative emission purge control system/Display range: without support <---->with support Without support - [Heated catalyst(Supp)] Indicating test on heat type catalyst/Display range: without support <---->with support Without support - [Catalyst Diagnosis(Supp)] Indicating catalyst test/Display range: without support <---->with support Without support - [EGR system(Rdy)] Indicating EGR system test/Display range: NO <---->YES / N/A YES / N/A - [O2 Heater Diagnosis(Rdy)] Indicating O2 sensor heater test/Display range: NO <---->YES / N/A YES / N/A - [Oxygen sensor(Rdy)] Indicating O2 sensor test/Display range: NO <---->YES / N/A YES / N/A - [A/C system refrigerant(Rdy)] Indicating refrigerant test on air conditioner system/Display range: NO <---->YES / N/A YES / N/A - [Secondary air system(Rdy)] Indicating secondary air system test/Display range: NO <---->YES / N/A YES / N/A - [Evaporative purge system(Rdy)] Indicating test on evaporative emission purge control system/Display range: NO <---->YES / N/A YES / N/A - [Heated catalyst(Rdy)] Indicating test on heat type catalyst/Display range: NO <---->YES / N/A YES / N/A - [Catalyst Diagnosis(Rdy)] Indicating catalyst test/Display range: NO <---->YES / N/A YES / N/A - [OBD System] Indicating OBD applicable law EOBD / OBD2 - [Lighted MI lamp history] Indicating distance record from MIL illumination/Display range: 0 to 65535 km - - [Component monitoring(Comp)] Indicating component monitor test/Display range: NO <---->YES / N/A YES / N/A - [Fuel system monitoring(Comp)] Indicating fuel system monitor test/Display range: NO <---->YES / N/A YES / N/A - [Misfire monitoring(Comp)] Indicating misfire monitor test/Display range: NO <---->YES / N/A YES / N/A - [Component monitoring(Enable)] Indicating component monitor test/Display range: NO / N/A <---->YES YES - [Fuel system monitoring(Enable)] Indicating fuel system monitor test/Display range: NO / N/A <---->YES NO / N/A - [Misfire monitoring(Enable)] Indicating misfire monitor test/Display range: NO / N/A <---->YES NO / N/A - [EGR system(Enable)] Indicating EGR system test/Display range: NO / N/A <---->YES NO / N/A - [O2 Heater Diagnosis(Enable)] Indicating O2 sensor heater test/Display range: NO / N/A <---->YES NO / N/A - [Oxygen sensor(Enable)] Indicating O2 sensor test/Display range: NO / N/A <---->YES NO / N/A - [A/C system refrigerant(Enable)] Indicating refrigerant test on air conditioner system/Display range: NO / N/A <---->YES NO / N/A - [Secondary air system(Comp)] Indicating secondary air system test/Display range: NO / N/A <---->YES NO / N/A - [Evaporative purge system(Enable)] Indicating test on evaporative emission purge control system/Display range: NO / N/A <---->YES NO / N/A - [Heated catalyst(Enable)] Indicating test on heat type catalyst/Display range: NO / N/A <---->YES NO / N/A - [Catalyst Diagnosis(Enable)] Indicating catalyst test/Display range: NO / N/A <---->YES NO / N/A - [EGR system(Comp)] Indicating EGR system test/Display range: NO <---->YES / N/A YES / N/A - [O2 Heater Diagnosis(Comp)] Indicating O2 sensor heater test/Display range: NO <---->YES / N/A YES / N/A - [Oxygen sensor(Comp)] Indicating O2 sensor test/Display range: NO <---->YES / N/A YES / N/A - [A/C system refrigerant(Comp)] Indicating refrigerant test on air conditioner system/Display range: NO <---->YES / N/A YES / N/A - [Secondary air system(Comp)] Indicating secondary air system test/Display range: NO <---->YES / N/A YES / N/A - [Evaporative purge system(Comp)] Indicating test on evaporative emission urge control system/Display range: NO <---->YES / N/A YES / N/A - [Heated catalyst(Comp)] Indicating test on heat type catalyst/Display range: NO <---->YES / N/A YES / N/A - [Catalyst Diagnosis(Comp)] Indicating catalyst test/Display range: NO <---->YES / N/A YES / N/A - [Time while MIL lighted] Indicating engine operation time from MIL illumination/Display range: 0 to 65535 min - - [Engine Speed] Indicating engine speed (CAN reception data)/Display range: 0 to 51199.21875 r/min 0 r/min: When engine is stopped (IG ON) When abnormal, there may be a CAN communication malfunction. [Coolant Temp.] Indicating coolant temperature (CAN reception data)/Display range: -40 to 215°C Gradually increasing: Cold start -->warmed up When abnormal, there may be a CAN communication malfunction. [Accel. Opening Angle] Indicating acceleration opening angle (CAN reception data)/Display range: 0 to 127.5 % 0%: Accelerator pedal not depressed When abnormal, there may be a CAN communication malfunction. [Throttle Opening Angle] Indicating throttle opening angle (CAN reception data)/Display range: 0 to 127.5 % 0%: When engine is stopped (IG ON) When abnormal, there may be a CAN communication malfunction. [Stop Light Switch] Indicating that the brake pedal is depressed/Display range: ON<---->OFF OFF -->ON: With brake pedal released -->depressed When abnormal, there may be a stop light switch ASSY signal malfunction. [Shift SW Status (P Range)] Indicating select lever in P position/Display range: ON<---->OFF ON: Select lever in P When abnormal, there may be a neutral start switch ASSY (P) signal malfunction. [Shift SW Status (R Range)] Indicating select lever in R position/Display range: ON<---->OFF OFF -->ON: Select lever in N-->R When abnormal, there may be a neutral start switch ASSY (R) signal malfunction. [Shift SW Status (N Range)] Indicating select lever in N position/Display range: ON<---->OFF ON: Select lever in N When abnormal, there may be a neutral start switch ASSY (N) signal malfunction. [Shift SW Status (D Range)] Indicating select lever in D position/Display range: ON<---->OFF OFF -->ON: Select lever in N-->D When abnormal, there may be a neutral start switch ASSY (D) signal malfunction. [Manual SW] Indicating M position/Display range: ON<---->OFF OFF -->ON: Select lever in D-->M When abnormal, there may be a transmission control switch (M) signal malfunction. [Up SW] Indicating transmission control switch (+)/Display range: ON<---->OFF OFF -->ON: Select lever in M--> "+" When abnormal, there may be a transmission control switch (SFTU) signal malfunction. [Down SW] Indicating transmission control switch (-)/Display range: ON<---->OFF OFF -->ON: Select lever in M--> "-" When abnormal, there may be a transmission control switch (SFTD) signal malfunction. [Snow Mode] Indicating SNOW mode status/Display range: ON<---->OFF OFF -->ON: 2nd start OFF -->ON When abnormal, there may be a pattern select SW system malfunction. [Snow SW] Indicating pattern select (SNOW) switch/Display range: ON<---->OFF OFF -->ON: Pattern select (SNOW) switch OFF-->ON When abnormal, there may be a pattern select (SNOW) switch malfunction. [Sport SW] Indicating pattern select (SPORT) switch/Display range: ON<---->OFF OFF -->ON: Pattern select (SPORT) switch OFF-->ON When abnormal, there may be a pattern select (SPORT) switch malfunction. [A/C Switch] Indicating A/C ON / OFF status/Display range: ON<---->OFF - - [TC Terminal] Indicating shorted (ON) condition of TC terminal (DLC3)/Display range: ON<---->OFF ON: TC terminal shorted - [Turbine Revolution Speed] Indicating input revolution speed/Display range: 0 to 12750 rpm Almost the same as engine idle speed When the vehicle is parked with select lever in P or N position (when engine idling) When abnormal, there may be an NT signal malfunction. 0 rpm: The vehicle is parked with select lever in D position When abnormal, there may be an NT signal malfunction. Almost the same as engine speed When driving at a constant speed When abnormal, there may be an NT signal malfunction. [AT Speed] Indicating output revolution speed/Display range: 0 to 255 km/h {158 MPH} 0 km/h {0 MPH}: When vehicle is parked When abnormal, there may be an SP2 signal malfunction. No significant fluctuation: When driving at a constant speed When abnormal, there may be an SP2 signal malfunction. [ATF Temp.] Indicating transmission oil temperature/Display range: -40 to 215°C Ambient air temperature: IG ON when the engine is cold When abnormal, the THO1 voltage may be abnormal. 50 to 100°C: After stall test When abnormal, the THO1 voltage may be abnormal. -40°C: When sensor is disconnected When abnormal, the THO1 voltage may be abnormal. 150°C or more: When sensor is shorted When abnormal, the THO1 voltage may be abnormal. [Shift Indicator Lamp UP Shift] Indicating illumination indication status on shift indicator lamp UP side/Display range: ON<---->OFF - - [Shift Indicator Lamp Down Shift] Indicating illumination indication status on shift indicator lamp DOWN side/Display range: ON<---->OFF - - [Sport Mode] Indicating SPORT mode status/Display range: ON<---->OFF OFF -->ON: SPORT mode OFF-->ON When abnormal, there may be a pattern select SW system malfunction. [Control the Shift Position] Indicating gear positions (ranges)/Display range: 1st to 6th Shifted into each gear position: Driving When abnormal, the VTA1 voltage may be abnormal. When abnormal, the VPA voltage may be abnormal. When abnormal, there may be an SPD signal malfunction. When abnormal, there may be a solenoid signal malfunction. [Lock up status] Indicating that lock-up is operating/Display range: ON<---->OFF OFF -->ON: Lock-up OFF -->ON When abnormal, the VTA1 voltage may be abnormal. When abnormal, the VPA voltage may be abnormal. When abnormal, there may be an NT signal malfunction. When abnormal, there may be an SP2 signal malfunction. When abnormal, there may be an SLU signal malfunction. [SLT Solenoid Status] Indicating line pressure control solenoid ASSY (SLT) operating status/Display range: ON<---->OFF OFF -->ON: Acceleration fully opened -->fully closed When abnormal, there may be a line pressure control solenoid ASSY (SLT) signal malfunction. [Activate the Lock Up (SLU)] Indicating lock-up control solenoid (SLU) operating status/Display range: ON<---->OFF OFF -->ON: Lock-up OFF -->ON When abnormal, there may be a lockup control solenoid (SLU) signal malfunction. [Last 5 Digits ECU Part Number] Indicating last 5 digits of ECM part number - - [# Codes(Include History)] Indicating the number of trouble codes which have not experienced normal driving cycle in consecutive 40 warming up - - [Number Of ALL DTCs] Indicating the number of all DTCs/Display range: 0 to 255 - - [Trip Count] Indicating the number of all DTCs/Display range: 0 to 65535 trip - - [Count] Indicating the way to count time after IG ON Normal count When abnormal, there may be a CAN communication malfunction. [Time Count] Indicating time elapsed after IG ON/Display range: 0 to 53687091100 ms - - SSM3 SCREEN: [INTEG. UNIT MODE] -->[CURRENT DATA DISPLAY & SAVE] Item name Description/display range Normal value Remarks [Stop Light Switch] Indicating that the brake pedal is depressed/Display range: ON<---->OFF OFF -->ON: With brake pedal released -->depressed When abnormal, there may be a stop light switch ASSY signal malfunction. [Shift P Signal] Indicating select lever in P position/Display range: ON<---->OFF ON: Select lever in P When abnormal, there may be a select lever P switch malfunction. [ABS_CM Power Voltage] Indicating IG power supply voltage/Display range: 0 to 21.4 V 11 to 14 V: During idling When abnormal, the IG voltage may be abnormal. [Shift Lock Solenoid] Indicating shift lock solenoid operation status/. Display range: ON<---->OFF OFF -->ON: Shift lock OFF -->ON When abnormal, there may be a shift lock solenoid malfunction.
2. Inspection with SSM3 (System Operation Check Mode) Use SSM3 to display the [System Operation Check Mode] screen according to the screen display and perform the system operation check. SSM3 SCREEN: [TRANSMISSION CONTROL SYSTEM] -->[WORK SUPPORT] -->[SYSTEM OPERATION CHECK MODE] Item name Description Restriction [Control the Shift Position] Setting to any shift position is possible Vehicle speed is less than 50 km/h {31 MPH} Any of the following is established. Throttle idling status Gear range 4th or lower [Activate the Solenoid(S1)] Turning ON<---->OFF of transmission 3 way solenoid ASSY (S1) is possible. Vehicle speed 0 km/h {0 MPH} P or N position Engine speed: 0 r/min [Activate the Solenoid(S2)] Turning ON<---->OFF of transmission 3 way solenoid ASSY (S2) is possible. Vehicle speed 0 km/h {0 MPH} P or N position Engine speed: 0 r/min [Activate the Solenoid(S3)] Turning ON<---->OFF of transmission 3 way solenoid ASSY (S3) is possible. Vehicle speed 0 km/h {0 MPH} P or N position Engine speed: 0 r/min [Activate the Solenoid(S4)] Turning ON<---->OFF of transmission 3 way solenoid ASSY (S4) is possible. Vehicle speed 0 km/h {0 MPH} P or N position Engine speed: 0 r/min [Activate the Solenoid(SL1)] MIN current <---->MAX current of clutch control solenoid No. 1 (SL1) is possible. Vehicle speed 0 km/h {0 MPH} P or N position Engine speed: 0 r/min [Activate the Solenoid(SL2)] MIN current <---->MAX current of clutch control solenoid No. 1 (SL2) is possible. Vehicle speed 0 km/h {0 MPH} P or N position Engine speed: 0 r/min [Activate the Lock Up] Lock up ON<---->OFF is possible. Throttle opening angle less than 35% Vehicle speed is 50 km/h {31 MPH} or more Gear range 5th or higher [Activate the Solenoid(SLU)] MIN current <---->MAX current of lock-up control solenoid (SLU) is possible. Vehicle speed 0 km/h {0 MPH} P or N position Engine speed: 0 r/min [Activate the Solenoid(SR)] Turning ON<---->OFF of transmission 3 way solenoid ASSY (SR) is possible. Vehicle speed 0 km/h {0 MPH} P or N position Engine speed: 0 r/min [Activate the Solenoid(SLT)] MIN current <---->MAX current of line pressure control solenoid ASSY (SLT) is possible. (MAX current -->duty ratio 100% (line pressure at idling)) (MIN current -->duty ratio 0% (line pressure at stall)) Vehicle speed 0 km/h {0 MPH} P or N position Engine speed: 0 r/min [TC and TE1] (1) Used when changing to the oil temperature detection mode - (1) Warning diagnoses are not displayed in a list. SSM3 SCREEN: [INTEG. UNIT MODE] -->[WORK SUPPORT] -->[SYSTEM OPERATION CHECK MODE] Item name Description Restriction [Shift Lock] Shift lock output ON<---->OFF is possible.

Monitor description

TCM observes inner operation. If a defect is found in inner operation, TCM turns on MIL and records diagnostic codes.

TCM observes inner operation. If a defect is found in inner operation, TCM turns on MIL and records diagnostic codes.

These diagnostic codes indicate problems of the wiring harness in the neutral start switch ASSY and neutral start switch ASSY circuit.

The neutral start switch ASSY detects the select lever position and sends signals to TCM.

For safety, the neutral start switch ASSY detects the select lever position. It is to allow the engine to start only when the select lever is in P or N position.

The neutral start switch ASSY sends signals corresponding to shift positions (P, R, N, D, or M) to TCM. When receiving 2 or more position signals at one time, TCM determines that the switch or related parts have a problem. TCM turns on MIL and records the diagnostic codes.

If open or short circuit is detected, all contacts of shift positions are turned to OFF.

This diagnostic code indicates that the automatic transmission fluid (ATF) temperature sensor output is abnormal and the sensor itself is defective. The ATF temperature sensor converts ATF temperature into electric resistance. TCM specifies ATF temperature based on the resistance and detects open or short circuit in the ATF temperature circuit or defects of the ATF temperature sensor.

If the vehicle drives for a certain period of time, the ATF temperature should rise. If the ATF temperature is less than 20°C and the input voltage fluctuation is 0.05 V or less after the vehicle drives for a certain period of time, TCM recognizes the defect and turns on MIL.

These diagnostic codes indicate that there is an open or short circuit in the automatic transmission fluid (ATF) temperature sensor circuit. The automatic transmission fluid (ATF) temperature sensor converts ATF temperature into electric resistance. TCM specifies ATF temperature based on the resistance and detects open or short circuit in the ATF temperature circuit. If the ATF temperature resistance is less than 0.049 V or more than 4.932 V, TCM recognizes it as a defect in the ATF sensor or wiring. TCM turns on MIL and records the diagnostic codes.

This diagnostic code indicates whether pulse is not output from the transmission revolution sensor (NT) or the output is very small. The TCM transmission revolution sensor (NT) terminal detects revolution speed signals from the transmission revolution sensor (NT) (input RPM). TCM compares the transmission revolution sensor (NT) and transmission revolution sensor (SP2) and outputs shift signals.

If the output shaft speed is 550 rpm or more* while the vehicle is driving in D position, TCM detects a defect, turns on MIL, and records the diagnostic code.

*: Engine speed is 400 rpm or more.

This diagnostic code indicates whether pulse is not output from the transmission revolution sensor (SP2) or the output is very small. The TCM transmission revolution sensor (SP2) terminal detects revolution speed signals from the transmission revolution sensor (SP2). TCM compares the transmission revolution sensor (NT) and transmission revolution sensor (SP2) and outputs shift signals.

If the output shaft speed calculated from the transmission revolution sensor (NT) is 300 rpm or more* while the vehicle is driving in D position, TCM detects a defect, turns on MIL, and records the diagnostic code.

*: Engine speed is 400 rpm or more.

TCM switches ON/OFF of the shift solenoid valve and transmits oil pressure to the valve body to command gear shift. This diagnostic code indicates that the sequence valve is locked in the direction the spring extends and shift to 6th gear is impossible.

This diagnostic code indicates "stuck ON" or "stuck OFF" of the transmission 3 way solenoid ASSY (S1).

TCM switches ON/OFF of the shift solenoid valve to command shifting. If the gear position commanded by TCM is different from the actual gear position, TCM turns on MIL and records the diagnostic code.

This diagnostic code indicates "stuck ON" or "stuck OFF" of the transmission 3 way solenoid ASSY (S2).

TCM switches ON/OFF of the shift solenoid valve to command shifting. If the gear position commanded by TCM is different from the actual gear position, TCM turns on MIL and records the diagnostic code.

This diagnostic code indicates "stuck ON" or "stuck OFF" of the transmission 3 way solenoid ASSY (S3).

TCM switches ON/OFF of the shift solenoid valve to command shifting. If the gear position commanded by TCM is different from the actual gear position, TCM turns on MIL and records the diagnostic code.

This diagnostic code indicates "stuck OFF" of the transmission 3 way solenoid ASSY (S4), "stuck ON" of the clutch control solenoid No. 1 (SL2), or a defect of the brake control valve. TCM switches ON/OFF of the shift solenoid valve to command shifting. If the gear position commanded by TCM is different from the actual gear position, TCM turns on MIL and records the diagnostic code.

This diagnostic code indicates open or short circuit in the clutch control solenoid No. 1 (SL1). TCM switches ON/OFF of the shift solenoid valve to command shifting. If there is open or short circuit in any of the shift solenoid valve circuits, TCM detects the defect, turns on MIL, and records the diagnostic code.

This diagnostic code indicates open or short circuit in the clutch control solenoid No. 1 (SL2). TCM switches ON/OFF of the shift solenoid valve to command shifting. If there is open or short circuit in any of the shift solenoid valve circuits, TCM detects the defect, turns on MIL, and records the diagnostic code.

These diagnostic codes indicate open or short circuit in the transmission 3 way solenoid ASSY (S1) circuit. If there is open or short circuit in any of the shift solenoid valve circuits, TCM detects the defect, turns on MIL, and records the diagnostic code.

These diagnostic codes indicate open or short circuit in the transmission 3 way solenoid ASSY (S2) circuit. If there is open or short circuit in any of the shift solenoid valve circuits, TCM detects the defect, turns on MIL, and records the diagnostic code.

These diagnostic codes indicate open or short circuit in the transmission 3 way solenoid ASSY (S3) circuit. If there is open or short circuit in any of the shift solenoid valve circuits, TCM detects the defect, turns on MIL, and records the diagnostic code.

These diagnostic codes indicate open or short circuit in the transmission 3 way solenoid ASSY (S4) circuit. If there is open or short circuit in any of the shift solenoid valve circuits, TCM detects the defect, turns on MIL, and records the diagnostic code.

These diagnostic codes indicate open or short circuit in the transmission 3 way solenoid ASSY (SR) circuit. If there is open or short circuit in any of the shift solenoid valve circuits, TCM detects the defect, turns on MIL, and records the diagnostic code.

TCM observes inner operation. If a defect is found in inner operation, TCM turns on MIL and records diagnostic codes.

The line pressure control solenoid ASSY (SLT) is controlled according to duty ratio which is predetermined by the transmission control computer ASSY based on signals from the accelerator position sensor and the transmission revolution sensor (NT, SP2). This adjusts line pressure to meet the throttle opening angle and engine output. The transmission control computer ASSY detects slippage of clutch, etc. based on the revolution speed of the transmission revolution sensor (NT, SP2).

TCM calculates the heat amount absorbed by friction material based on the difference between turbine speed and output shaft speed (slipping clutch). When the amount of heat absorption exceeds a certain value, TCM turns on MIL and outputs diagnostic codes.

If open or short circuit is detected in the circuit, TCM recognizes it as a malfunction.

TCM turns on MIL and records the diagnostic codes.

The torque converter lock-up is controlled by TCM based on the transmission revolution sensor (NT, SP2), engine rpm, engine load, engine temperature, vehicle speed, transmission temperature, and selected gear. TCM compares engine rpm (NE) with input turbine rpm (NT) to determine the lock-up status of the torque converter. TCM compares input turbine rpm (NT) and output shaft rpm (SP2) to calculate the actual transmission gear. If the condition is appropriate, TCM applies control voltage to the lockup control solenoid (SLU) and requires "lock up". When the lock-up control solenoid (SLU) turns to ON, it applies pressure to the lock up relay valve to lock the torque converter clutch.

If TCM does not detect lock up after the lock up is requested or detects lock up even though it is not requested, TCM recognizes it as a malfunction of the lock-up control solenoid (SLU) or lock up system performance. TCM turns on MIL and records the diagnostic codes.

If open or short circuit is detected in the lock-up control solenoid ASSY (SLU) circuit, TCM recognizes it as a defect. TCM turns on MIL and records the diagnostic code.

When the shift is in M position, it can be changed to any gear using the transmission shift switch (paddle shifter) of the steering wheel ASSY.

Also, when operating the switch of the transmission shift of the steering wheel ASSY while driving in D position, gear selection in D position is initiated and any gear can be selected.

Scheme 1

See also:
• DTC TABLE