Scheme 308
MONITOR DESCRIPTION
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 engine can be started only when the vehicle is in P or N shift position.
When the park/neutral position switch sends more than one signal at a time from switch positions P, R, N or D, the ECM interprets this as a fault in the switch. The ECM will turn on the MIL and store the DTC.
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The automatic transmission fluid (ATF) temperature sensor converts 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 circuit. If the resistance value of the ATF temperature is less than 79 ohm *1 or more than 156 kohm *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.
*1: 150°C (302°F) or more is indicated regardless of the actual ATF temperature.
*2: -40°C (-40°F) is indicated regardless of the actual ATF temperature.
HINT
The ATF temperature can be checked on the OBD II scan tool or hand-held tester display.
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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 circuit or a fault of the ATF temperature sensor.
After running the vehicle for a certain period, the ATF temperature should increase. If the ATF temperature is below 10°C (50°F) after running the vehicle for a certain period, the ECM interprets this as a fault, and turns on the MIL.
When the ATF temperature is 110°C (230°F) or more after 18 minutes of engine cold start, the ECM also determines this as a fault, turns on the MIL, and stores the DTC.
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The NT terminal of the ECM detects the revolving signal from speed sensor (NT) (input RPM). The ECM outputs a gearshift signal comparing the speed sensor (NT) with the speed sensor (NC).
While the vehicle is operating in the 2nd, 3rd, 4th or 5th gear position in the shift position of D, if the input shaft revolution is less than 300 rpm *1 although the output shaft revolution is more than 1,000 rpm *2 , the ECM detects the trouble, illuminates the MIL and stores the DTC.
*1: Pulse is not output or is irregularly output.
*2: The vehicle speed is 50 km/h (31 mph) or more.
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When the stop light switch remains ON during "stop and go" driving, the ECM interprets this as a fault in the stop light switch and the MIL comes on and the ECM stores the DTC. The vehicle must stop and go (3 km/h (2 mph) to 30 km/h (19 mph)) ten times for two driving cycles in order to detect malfunction.
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SYSTEM DESCRIPTION
The ECM uses the signals from the throttle position sensor, air-flow meter 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 trouble of the shift solenoid valve SL, valve body and torque converter clutch or automatic transaxle (clutch, brake or gear etc.).
Scheme 321
Torque converter lock-up is controlled by the ECM based on speed sensor (NT), speed sensor (NC), engine rpm, 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 rpm (NE) to the input turbine rpm (NT). The ECM calculates the actual transmission gear by comparing input turbine rpm (NT) to counter gear rpm (NC). When conditions are appropriate, the ECM requests "lock-up" by applying control voltage to shift solenoid SL. When the SL is turned on, solenoid SL 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 torque converter clutch performance. The ECM will turn on the MIL and store the DTC.
Example
When any of the following is met, the system judges it as a malfunction.
- There is a difference in rotation between before and after torque converters even when the ECM commands lock-up. (Engine speed is at least 75 rpm greater than input speed.)
- There is no difference in rotation between before and after torque converters even when the ECM commands lock-up off. (The difference between engine speed and input speed is less than 35 rpm.)
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- Check solenoid valve SL operation PREPARATION: Remove the oil pan. Remove the solenoid valve SL. CHECK: Applying 490 kPa (5 kgf/cm 2 , 71 psi) of compressed air, check that the solenoid valve does leak air. When battery voltage is supplied to the shift solenoid valve, check that the solenoid valve closes. OK: Solenoid valve does leak air. Solenoid valve closes. NG : Replace the solenoid valve SL. OK : Go to next step.
- Check valve body (See «PROBLEM SYMPTOMS TABLE»(ref-206116-S29705672992005112400000) ). NG: Repair or replace the valve body. OK: Go to next step.
- Check the torque converter clutch (See «TORQUE CONVERTER CLUTCH AND DRIVE PLATE»(/toyota/celica/t230-2002-2006/remont/automatic-trans/#automatic-transmission-torque-converter-clutch-and-drive-plate-u341e) ). NG : Repair the torque converter clutch. OK : Repair the transaxle (See «COMPONENTS»(/toyota/celica/t230-2002-2006/remont/automatic-trans/#automatic-transmission-unit-u341e) ).
Based on the signals from the Throttle Position Sensor, the Airflow Meter and the Crankshaft Position Sensor, the ECM sends a signal to the SL Solenoid Valve to regulate the hydraulic pressure and provide smoother gearshifts. The shift-solenoid valve SL responds to commands from the ECM. The valve controls the look-up relay valve to perform the torque-converter lock-up function. If the ECM detects an open or short circuit for shift-solenoid SL, it will illuminate the MIL and store the DTC.
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- Check transmission wire. PREPARATION: Disconnect the transmission wire connector. CHECK: Measure resistance between SL of transmission wire and body ground. OK: Resistance: 11 to 15 ohm at 20 °C (68°F) NG : Go to step 3 . OK : Go to next step.
- Measure resistance between terminal SL of ECM and body ground. PREPARATION: Connect the transmission wire connector. Remove the ECM hood. Disconnect the connector from ECM. CHECK: Measure resistance between terminal SL of ECM and body ground. OK: Resistance: 11 to 15 ohm at 20°C (68 °F) NG: Repair or replace the harness or connector (See «HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE»(ref-206072-S25601918062005112300000) ). OK: Check and replace the ECM (See «HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE»(ref-206072-S25601918062005112300000) ).
- Check shift solenoid valve SL. PREPARATION: Jack up the vehicle. Remove the oil pan. Disconnect the shift solenoid valve SL connector. Remove the shift solenoid valve SL. CHECK: Measure resistance between terminal SL of shift solenoid valve and solenoid body. OK: Resistance: 11 to 15 ohm at 20 °C (68 °F) NG: Replace the shift solenoid valve SL. OK: Repair or replace the transmission wire (For U240E, see «ATF TEMPERATURE SENSOR AND SOLENOID CONNECTOR»(ref-166573-S09017451022004100400000). For U341E, see «ATF TEMPERATURE SENSOR AND SOLENOID CONNECTOR»(ref-167041-S32203489542004100500000) in Transmission ).
The ECM uses signals from the vehicle speed sensor to detect the actual gear position (1st, 2nd, 3rd or O/D gear).
Then the ECM compares the actual gear with the shift schedule in the ECM memory to detect mechanical trouble of the shift solenoid valves and valve body.
Scheme 333
HINT
Check the shift solenoid valve No. 1 when DTC P0751 is output and check the shift solenoid valve No. 2 when DTC P0756 is output.
The ECM commands gear shifts by turning the shift solenoid valves "ON/OFF". According to the input shaft revolution, intermediate (counter) shaft revolution and output shaft revolution, the ECM detects the actual gear position (1st, 2nd, 3rd or O/D gear position). 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.
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- Check shift solenoid valve No. 1 or No. 2 operation. PREPARATION: Remove the oil pan. Remove the shift solenoid valve No. 1 or No. 2. CHECK: By applying 490 kPa (5 kgf/cm 2 , 71 psi) of compressed air, check that the solenoid valve does leak air. When battery voltage is supplied to the shift solenoid valve, check that the valve closes. OK: Solenoid valve does leak air. Solenoid valve closes. NG : Replace the shift solenoid valve No. 1 or No. 2. OK : Go to next step.
- Check the valve body (See «PROBLEM SYMPTOMS TABLE»(ref-206116-S29705672992005112400000) ). NG: Repair or replace the valve body. OK: Repair or replace the transaxle.
The ECM commands gearshift 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 and illuminates the MIL and stores the DTC. And the ECM performs the fail-safe function and turns the other shift solenoid valves in good condition "ON/OFF" (In case of an open or short circuit, the ECM stops sending current to the circuit.).
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- Check transmission wire. PREPARATION: Disconnect the transmission wire connector. CHECK: Measure resistance between S1 and S2 of transmission wire connector and body ground. OK: Resistance: 11 to 15 ohm at 20 °C (68°F) NG : Go to step 3 . OK : Go to next step.
- Measure resistance between terminal S1 or S2 of ECM and body ground. PREPARATION: Connect the transmission wire connector. Remove the ECM hood. Disconnect the connector of the ECM. CHECK: Measure resistance between terminal S1 or S2 of ECM and body ground. OK: Resistance: 11 to 15 ohm at 20 °C (68 °F) NG: Repair or replace the harness or connector (See «HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE»(ref-206072-S25601918062005112300000) ). OK: Check and replace the ECM (See «HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE»(ref-206072-S25601918062005112300000) ).
- Check shift solenoid valve No. 1 or No. 2. PREPARATION: Jack up the vehicle. Remove the oil pan. Disconnect the solenoid connector. Remove the shift solenoid valve No. 1 or No. 2. CHECK: Measure resistance between solenoid connector and body ground. OK: Resistance: 11 to 15 ohm at 20 °C (68 °F) NG: Replace the solenoid valve. OK: Repair or replace transmission wire (See «HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE»(ref-206072-S25601918062005112300000) ).
The ECM reduces the gear shift shock when shifting from the N position to the D position and from 3rd gear to 4th gear by regulating the hydraulic line pressure. To regulate the pressure, the ECM controls shift-solenoid ST with a duty-cycle signal that adjusts the line-pressure.
If the ECM detects an open or short in the shift-solenoid ST circuit, it will illuminate the MIL and store the DTC.
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- Check transmission wire. PREPARATION: Disconnect the transmission wire connector. CHECK: Measure resistance between ST of transmission wire and body ground. OK: Resistance: 11 to 15 ohm at 20 °C (68 °F) NG : Go to step 3 . OK : Go to next step.
- Measure resistance between terminal ST of ECM and body ground. PREPARATION: Connect the transmission wire connector. Remove the ECM hood. Disconnect the connector from ECM. CHECK: Measure resistance between terminal ST of ECM and body ground. OK: Resistance: 11 to 15 ohm at 20 °C (68 °F) NG: Repair or replace the harness or connector (See «HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE»(ref-206072-S25601918062005112300000) ). OK: Check and replace the ECM (See «HOW TO USE THE DIAGNOSTIC CHART AND INSPECTION PROCEDURE»(ref-206072-S25601918062005112300000) ).
- Check shift solenoid valve ST. Electrical check: PREPARATION: Jack up the vehicle. Remove the oil pan. Remove the shift solenoid valve ST. CHECK: Measure resistance between solenoid connector and body ground. Connect positive (+) lead to terminal of solenoid connector, negative (-) lead to solenoid body. OK: Resistance: 11 to 15 ohm at 20 °C (68 °F) The solenoid makes an operating noise. Mechanical check: PREPARATION: Jack up the vehicle. Remove the oil pan. Disconnect the solenoid connector. Remove the shift solenoid valve ST. CHECK: Applying 490 kPa (5 kgf/cm 2, 71 psi) of compressed air, check that the solenoid valves do not leak air. When battery voltage is supplied to the shift solenoid valves, check that the solenoid valve opens. OK: Solenoid valve does not leak air. Solenoid valve opens. NG: Replace the shift solenoid valve ST. OK: Repair or replace the transmission wire (For U240E, see «ATF TEMPERATURE SENSOR AND SOLENOID CONNECTOR»(ref-166573-S09017451022004100400000). For U341E, see «ATF TEMPERATURE SENSOR AND SOLENOID CONNECTOR»(ref-167041-S32203489542004100500000) in Transmission ).
Scheme 355
The throttle pressure that is applied to the primary regulator valve (which modulates line pressure) causes the shift solenoid valve SLT, under electronic control, to precisely and minutely modulate and generate line pressure according to the accelerator pedal effort, or engine power output detected.
This controls the line pressure and provides smooth shifting characteristics.
Upon receiving the throttle valve opening angle signal, ECM controls the line pressure by sending a predetermined (*) duty ratio to the solenoid valve, modulating the line pressure, generating throttle pressure.
(*) Duty Ratio
The duty ratio is the ratio of the period of continuity in one cycle. For example, if A is the period of continuity in one cycle, and B is the period of non-continuity, then
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HINT
Refer to the chart for the waveform between terminals SLT + and SLT - during engine idling.
Scheme 359
When an open or short in the linear solenoid valve (SLT) circuit is detected, the ECM interprets this as a fault. The ECM will turn on the MIL and store the DTC.
