Scheme 185
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 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 17 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 or O/D 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 DSL, valve body and torque converter clutch.
Scheme 198
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 DSL. When the DSL is turned on, solenoid DSL 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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Scheme 202
- Check solenoid valve DSL operation. PREPARATION: Remove the oil pan. Remove the shift solenoid valve DSL. 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 DSL. OK : Go to next step.
- Check valve body (See «PROBLEM SYMPTOMS TABLE»(ref-206114-S19560572682005112400000) ). NG: Repair or replace the valve body. OK: Replace the torque converter clutch (See «AUTOMATIC TRANSAXLE UNIT»(/toyota/celica/t230-2002-2006/remont/automatic-trans/#automatic-transmission-unit-u240e) ).
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 203
HINT
Check the shift solenoid valve SL1 when DTC P0746 is output, check the shift solenoid valve SL2 when DTC P0776 is output and check shift solenoid S4 when DTC P0766 is output.
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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The NC terminal of ECM detects the revolving signal from speed sensor (NC) (output 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 or O/D gear position in the shift position of D, if the counter gear 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.
When the ECM detects this malfunction, the ECM performs the fail-safe function and outputs a gearshift signal based on the signal from the speed sensor (NT).
*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 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.
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Scheme 211
Based on the signals from the Throttle Position Sensor, the Airflow Meter and the Crankshaft Position Sensor, the ECM sends a signal to the DSL Solenoid Valve to regulate the hydraulic pressure and provide smoother gearshifts. The shift-solenoid valve DSL 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 DSL, 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 DSL 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 terminals DSL of ECM and body ground. PREPARATION: Connect the transmission wire connector. Remove the ECM hood. Disconnect the connector from ECM. CHECK: Measure resistance between terminals DSL and E1 of ECM. 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 DSL. PREPARATION: Jack up the vehicle. Remove the oil pan. Disconnect the shift solenoid valve DSL connector. Remove the shift solenoid valve DSL. CHECK: Measure resistance between terminal DSL of shift solenoid valve and solenoid body. Connect positive (+) lead to terminal of solenoid connector, negative (-) lead to solenoid body. OK: Resistance: 11 to 15 ohm The shift solenoid valve DSL makes operation noise. NG : Replace the shift solenoid valve DSL. OK : Repair or replace the transmission wire (See ATF Temperature Sensor in Transmission ).