Electronic A/t Shift Lever System (Diagnostic Codes & Circuit Tests): Overview Lexus CT I

DESCRIPTION

The shift control actuator assembly consists of a parking lock motor and rotation angle sensor. The transmission control ECU assembly receives a P position switch signal from the power management control ECU (HV CPU) and activates the parking lock motor by controlling current, causing the parking lock mechanism to switch. The transmission control ECU assembly also detects the rotor rotation angle through the rotation angle sensor to control timing of current application to the coils. The transmission control ECU assembly stores this DTC when it detects a malfunction in the shift control actuator system.

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The transmission control ECU assembly receives a P position switch signal from the power management control ECU (HV CPU) and then activates the shift control actuator assembly. At the same time, the transmission control ECU assembly detects the length of time it takes for the parking lock mechanism to switch. The transmission control ECU assembly stores this DTC when this length of time is longer than specified.

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The P CON MTR relay (transaxle parking lock control relay) is activated by output voltage from the transmission control ECU assembly and supplies power to the shift control actuator assembly (parking lock motor). The transmission control ECU assembly stores this DTC when it detects a malfunction in the P CON MTR relay (transaxle parking lock control relay).

The shift control actuator assembly consists of a parking lock motor and rotation angle sensor. The transmission control ECU assembly receives a P position switch signal from the power management control ECU (HV CPU) and activates the parking lock motor by controlling current, causing the parking lock mechanism to switch. The transmission control ECU assembly stores these DTCs when it detects a malfunction in the parking lock motor system.

The shift control actuator assembly consists of a parking lock motor and rotation angle sensor. The transmission control ECU assembly receives a P position switch signal from the power management control ECU (HV CPU) and activates the parking lock motor by controlling current, causing the parking lock mechanism to switch. The transmission control ECU assembly stores this DTC when it detects a malfunction in the parking lock motor system and/or the ground circuit.

Scheme 217

The transmission control ECU assembly monitors its internal operation and it will store this DTC when it detects an EEPROM malfunction. If this DTC is output, replace the transmission control ECU assembly.

Auxiliary battery voltage will be applied to the +B terminal when the power switch is turned on (IG). When a +B terminal voltage malfunction is detected, the transmission control ECU assembly stores this DTC.

Auxiliary battery voltage is constantly applied to terminal BATT. This voltage is used to power the transmission control ECU assembly memory. The transmission control ECU assembly stores this DTC when it detects a malfunction related to terminal BATT.

HINT

When there is an open or short in the BATT circuit, information on the actuator position (park (P) selected or a shift state other than park (P) selected) stored in the transmission control ECU assembly is cleared every time the power switch is turned off. Therefore, the ECU works to recognize the position each time the power switch is turned on (IG). As a result, the time from when the power switch is turned on (IG) until "READY" is indicated may become longer than normal.

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1. INSPECT FUSE (P CON MAIN) Remove the P CON MAIN fuse from the engine room junction block assembly. Measure the resistance according to the value(s) in the table below. Standard Resistance Tester Connection Condition Specified Condition P CON MAIN fuse Always Below 1 ohms TEXT IN ILLUSTRATION *1 Engine Room Junction Block Assembly *2 P CON MAIN Fuse Install the P CON MAIN fuse. NG --> REPLACE FUSE (P CON MAIN) OK: Go to next step
2. READ VALUE USING TECHSTREAM (BATTERY VOLTAGE VALUE) Connect the Techstream to the DLC3. Turn the power switch on (IG). Enter the following menus: Chassis / Transmission Control / Data List / Battery Voltage Value. Read the Data List displayed on the Techstream. Result Tester Display Condition Specified Condition Battery Voltage Value Always 9 to 14 V Turn the power switch off. NG --> See step 3 OK --> See step 4
3. CHECK HARNESS AND CONNECTOR (TRANSMISSION CONTROL ECU ASSEMBLY - P CON MAIN FUSE) Disconnect connector A21 from the transmission control ECU assembly. Disconnect the P CON MAIN fuse from the engine room junction block assembly. Measure the resistance according to the value(s) in the table below. Standard Resistance (Check for Open) Tester Connection Switch Condition Specified Condition A21-15 (BATT) - 2 (P CON MAIN fuse) Power switch off Below 1 ohms Standard Resistance (Check for Short) Tester Connection Switch Condition Specified Condition A21-15 (BATT) or 2 (P CON MAIN fuse) - Body ground and other terminals Power switch off 10 kohms or higher TEXT IN ILLUSTRATION *1 Engine Room Junction Block Assembly *a Front view of wire harness connector (to Transmission Control ECU Assembly) *b P CON MAIN Fuse Connector of Engine Room Junction Block Assembly NOTE: Be careful not to break the fuse holder by forcing the tester probes into it during this inspection. Install the P CON MAIN fuse. Connect the transmission control ECU assembly connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> CHECK AND REPAIR POWER SOURCE CIRCUIT
4. REPLACE TRANSMISSION CONTROL ECU ASSEMBLY. Refer to «COMPONENTS»(ref-568724-S04696024902013072300000)

The transmission control ECU assembly receives a P position switch signal from the power management control ECU (HV CPU) and activates the parking lock motor by controlling current, causing the parking lock mechanism to switch. The transmission control ECU assembly stores this DTC when it detects a communication error between the power management control ECU (HV CPU) and the transmission control ECU assembly.

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1. CHECK TRANSMISSION CONTROL ECU ASSEMBLY Turn the power switch on (IG). Connect an oscilloscope between the transmission control ECU assembly terminals specified in the table below, and measure the waveform. Item Contents Symbols A22-22 (PCON) - A22-1 (E1) Tool setting 10 V/DIV., 10 msec./DIV. Vehicle condition Power switch on (IG) OK The waveform is similar to that shown in the illustration. TEXT IN ILLUSTRATION *a Component with harness connected (Transmission Control ECU Assembly) *b Waveform HINT: Perform this inspection with the connector connected. Turn the power switch off. NG --> See step 2 OK --> See step 3
2. CHECK HARNESS AND CONNECTOR (TRANSMISSION CONTROL ECU - POWER MANAGEMENT CONTROL ECU) Disconnect connector A22 from the transmission control ECU assembly. Disconnect connector A20 from the power management control ECU. Measure the resistance according to the value(s) in the table below. Standard Resistance (Check for Open) Tester Connection Switch Condition Specified Condition A22-22 (PCON) - A20-22 (PCON) Power switch off Below 1 ohms Standard Resistance (Check for Short) Tester Connection Switch Condition Specified Condition A22-22 (PCON) or A20-22 (PCON) - Body ground and other terminals Power switch off 10 kohms or higher TEXT IN ILLUSTRATION *a Front view of wire harness connector (to Transmission Control ECU Assembly) *b Rear view of wire harness connector (to Power Management Control ECU) Connect the power management control ECU connector. Connect the transmission control ECU assembly connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 4
3. REPLACE TRANSMISSION CONTROL ECU ASSEMBLY. Refer to «COMPONENTS»(ref-568724-S04696024902013072300000)
4. REPLACE POWER MANAGEMENT CONTROL ECU. Refer to «COMPONENTS»(/lexus/ct/i-2010-2014/remont/body-electrical/#power-distribution-service-information)

The transmission control ECU assembly receives a P position switch signal from the power management control ECU (HV CPU) and activates the parking lock motor by controlling current, causing the parking lock mechanism to switch. When the power management control ECU (HV CPU) detects a malfunction with the P position switch or P position signal, it sends an information signal to the transmission control ECU assembly. After receiving this signal, the transmission control ECU assembly stores this DTC.

Scheme 224

The transmission control ECU assembly receives signals from the main body ECU via CAN communication. When a CAN communication malfunction is detected, the transmission control ECU assembly stores this DTC.

The indicator light comes on when the P position switch (transmission shift main switch) is pressed (park (P) selected), goes off when a shift state other than park (P) is selected and goes off when a system malfunction occurs. Then an error message is displayed on the multi-information display.

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1. CHECK P POSITION SWITCH (INDICATOR LIGHT) Turn the power switch on (IG). Depress the brake pedal and move the shift lever to select neutral (N). Inspect the indicator light condition by operating the P position switch (transmission shift main switch). Result Condition of Indicator Light Proceed to Indicator light does not go off. (Remains on) A Indicator light does not come on. B Turn the power switch off. B --> See step 4 A: Go to next step
2. CHECK P POSITION SWITCH (INDICATOR LIGHT) Disconnect connector A21 from the transmission control ECU assembly. Turn the power switch on (IG). Inspect the indicator light condition by operating the P position switch (transmission shift main switch). Result Condition of Indicator Light Proceed to Indicator light does not go off. (Remains on) A Indicator light goes off. B NOTE: Turning the power switch on (IG) with the transmission control ECU assembly connector disconnected causes other DTCs to be stored. Clear the DTCs after performing this inspection. Turn the power switch off. Connect the transmission control ECU assembly connector. B --> See step 7 A: Go to next step
3. CHECK HARNESS AND CONNECTOR (TRANSMISSION CONTROL ECU - P POSITION SWITCH) Disconnect connector A21 from the transmission control ECU assembly. Disconnect connector H81 from the P position switch (transmission shift main switch). Measure the resistance according to the value(s) in the table below. Standard Resistance (Check for Short) Tester Connection Switch Condition Specified Condition A21-20 (IND) or H81-7 (IND-) - Body ground and other terminals Power switch off 10 kohms or higher TEXT IN ILLUSTRATION *a Front view of wire harness connector (to Transmission Control ECU Assembly) *b Front view of wire harness connector (to P Position Switch (Transmission Shift Main Switch)) Connect the P position switch (transmission shift main switch) connector. Connect the transmission control ECU assembly connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> REPLACE P POSITION SWITCH
4. CHECK HARNESS AND CONNECTOR (P POSITION SWITCH POWER SOURCE CIRCUIT) Disconnect the connector from the P position switch (transmission shift main switch). Measure the voltage according to the value(s) in the table below. Standard Voltage Tester Connection Switch Condition Specified Condition H81-6 (IND+) - Body ground Power switch off 9 to 14 V TEXT IN ILLUSTRATION *a Front view of wire harness connector (to P Position Switch (Transmission Shift Main Switch)) Connect the P position switch (transmission shift main switch) connector. NG --> CHECK AND REPAIR POWER SOURCE CIRCUIT OK: Go to next step
5. INSPECT P POSITION SWITCH Disconnect the connector from the P position switch (transmission shift main switch). Apply auxiliary battery voltage between terminals H81-6 (IND+) and H81-7 (IND-) and check the indicator light. Result Condition Specified Condition Auxiliary battery voltage applied between terminals H81-6 (IND+) and H81-7 (IND-) Comes on TEXT IN ILLUSTRATION *a Component without harness connected (P Position Switch (Transmission Shift Main Switch)) HINT: Terminals No. 1 and No. 8 on the component side connector are empty. Connect the P position switch (transmission shift main switch) connector. NG --> REPLACE P POSITION SWITCH OK: Go to next step
6. CHECK HARNESS AND CONNECTOR (TRANSMISSION CONTROL ECU - P POSITION SWITCH) Disconnect connector A21 from the transmission control ECU assembly. Disconnect the connector from the P position switch (transmission shift main switch). Measure the resistance according to the value(s) in the table below. Standard Resistance (Check for Open) Tester Connection Switch Condition Specified Condition A21-20 (IND) - H81-7 (IND-) Power switch off Below 1 ohms TEXT IN ILLUSTRATION *a Front view of wire harness connector (to Transmission Control ECU Assembly) *b Front view of wire harness connector (to P Position Switch (Transmission Shift Main Switch)) Connect the P position switch (transmission shift main switch) connector. Connect the transmission control ECU assembly connector. NG --> REPAIR OR REPLACE HARNESS OR CONNECTOR OK --> See step 7
7. REPLACE TRANSMISSION CONTROL ECU ASSEMBLY. Refer to «COMPONENTS»(ref-568724-S04696024902013072300000)

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• COMPONENTS
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