Automatic Transmission Electronic Controlled (ECT) - A750E/A750F - Diagnostics: Overview Toyota 4Runner IV

SYSTEM DESCRIPTION

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

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1. Inspect Shift Solenoid Valve (S1) Remove the shift solenoid valve S1. Measure the resistance between the solenoid connector and the solenoid body. OK : Resistance: 11-15 ohm at 20°C (68°F) Connector positive (+) lead to the terminal of solenoid connector, negative (-) lead to the solenoid body. OK : The solenoid makes an operating noise. NG : Replace Shift Solenoid Valve (S1) (See SHIFT SOLENOID VALVE ) OK : Go to Next Step
2. Inspect Transmission Valve Body Assy (See «PROBLEM SYMPTOMS TABLE»(ref-190084-S25026597502005091300000) ) NG: Repair Or Replace Transmission Valve Body Assy OK: Repair Or Replace Automatic Transmission Assy (See AUTOMATIC TRANSMISSION ASSY )

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

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1. Inspect Shift Solenoid Valve (S2) Remove the shift solenoid valve S2. Measure the resistance between the solenoid connector and the solenoid body. OK : Resistance: 11 - 15 ohm at 20°C (68°F) Connector positive (+) lead to the terminal of solenoid connector, negative (-) lead to the solenoid body. OK : The solenoid makes an operating noise. NG : Replace Shift Solenoid Valve (S2) (See SHIFT SOLENOID VALVE ) OK : Go to Next Step
2. Inspect Transmission Valve Body Assy (See «PROBLEM SYMPTOMS TABLE»(ref-190084-S25026597502005091300000) ) NG: Repair Or Replace Transmission Valve Body Assy OK: Repair Or Replace Automatic Transmission Assy (See AUTOMATIC TRANSMISSION )

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

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1. Inspect Shift Solenoid Valve (SR) Remove the shift solenoid valve SR. Measure the resistance between the solenoid connector and the solenoid body. OK : Resistance: 11 - 15 ohm at 20°C (68°F) Connector positive (+) lead to the terminal of solenoid connector, negative (-) lead to the solenoid body. OK : The solenoid makes an operating noise. NG : Replace Shift Solenoid Valve (SR) (See SHIFT SOLENOID VALVE ) OK : Go to Next Step
2. Inspect Shift Solenoid Valve SL1 Remove the shift solenoid valve SL1. Measure the resistance between terminals. OK : Resistance: 5.0 - 5.6 ohm at 20°C (68°F) Connect the positive (+) lead with a 21 W bulb to terminal 2 and the negative (-) lead to terminal 1 of the solenoid valve connector, then check the movement of the valve. OK : The solenoid makes an operating noise. NG : Replace Shift Solenoid Valve SL1 (See SHIFT SOLENOID VALVE ) OK : Go to Next Step
3. Inspect Transmission Valve Body Assy (See «PROBLEM SYMPTOMS TABLE»(ref-190084-S25026597502005091300000) ) NG: REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSY (See TRANSMISSION VALVE BODY ASSY ) OK: REPAIR OR REPLACE AUTOMATIC TRANSMISSION ASSY (See AUTOMATIC TRANSMISSION ASSY )

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

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1. Inspect Shift Solenoid Valve SL2 Remove the shift solenoid valve SL2. Measure the resistance between terminals. OK : Resistance: 5.0 - 5.6 ohm at 20°C (68°F) Connect the positive (+) lead with a 21 W bulb to terminal 2 and the negative (-) lead to terminal 1 of the solenoid valve connector, then check the movement of the valve. OK : The solenoid makes an operating noise. NG : Replace Shift Solenoid Valve SL2 (See SHIFT SOLENOID VALVE ) OK : Go to Next Step
2. Inspect Transmission Valve Body Assy (See «PROBLEM SYMPTOMS TABLE»(ref-190084-S25026597502005091300000) ) NG: Repair Or Replace Transmission Valve Body Assy (See TRANSMISSION VALVE BODY ASSY ) OK: Repair Or Replace Automatic Transmission Assy (See AUTOMATIC TRANSMISSION ASSY )

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

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The ECM calculates the shifting condition by using the signals from the vehicle speed sensor, throttle position sensor, etc.. And compares this result with the signal that ECM sends to SLT to detect mechanical trouble of the shift solenoid valve SLT, valve body, torque converter clutch and automatic transmission assembly (clutch, brake or gear etc.).

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1. Inspect Shift Solenoid Valve (SLT) Remove the shift solenoid valve SLT. Measure the resistance between terminals. OK : Resistance: 5.0 - 5.6 ohm at 20°C (68°F) Connect the positive (+) lead with a 21 W bulb to terminal 2 and the negative (-) lead to terminal 1 of the solenoid valve connector, then check the movement of the valve. OK : The solenoid makes an operating noise. NG : Replace Shift Solenoid Valve (SLT) (See SHIFT SOLENOID VALVE ) OK : Go to Next Step
2. Inspect Transmission Valve Body Assy (See «PROBLEM SYMPTOMS TABLE»(ref-190084-S25026597502005091300000) ) NG: Repair Or Replace Transmission Valve Body Assy (See TRANSMISSION VALVE BODY ASSY ) OK: Repair Or Replace Automatic Transmission Assy (See AUTOMATIC TRANSMISSION ASSY )

The ECM uses the signals from the Throttle Position Sensor and Air-flow Meter 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 trouble of the shift solenoid valve SLU, valve body, torque converter clutch and automatic transmission assembly (clutch, brake or gear etc.).

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1. Inspect Shift Solenoid Valve (SLU) Remove the shift solenoid valve SLU. Measure the resistance between terminals. OK : Resistance: 5.0 - 5.6 ohm at 20°C (68°F) Connect the positive (+) lead with a 21 W bulb to terminal 2 and the negative (-) lead to terminal 1 of the solenoid valve connector, then check the movement of the valve. OK : The solenoid makes an operating noise. NG : Replace Shift Solenoid Valve (SLU) (See SHIFT SOLENOID VALVE ) OK : Go to Next Step
2. Inspect Transmission Valve Body Assy (See «PROBLEM SYMPTOMS TABLE»(ref-190084-S25026597502005091300000) ) NG: Repair Or Replace Transmission Valve Body Assy (See TRANSMISSION VALVE BODY ) OK: Go to Next Step
3. INSPECT TORQUE CONVERTER CLUTCH ASSY (See TORQUE CONVERTER CLUTCH ASSY ) OK : Repair Or Replace Automatic Transmission Assy (SeeAUTOMATIC TRANSMISSION ASSY ) NG : Replace Torque Converter Clutch Assy (See TORQUE CONVERTER CLUTCH ASSY )

See also:
• COMBINATION METER - DIAGNOSTICS