LEXUS SC400 1991 Service Repair Manual

Chapter 3. Off±Vehicle Repair
( : '94 A340E and A341E AUTOMATIC TRANSMISSION Repair Manual for LEXUS SC400)
AT±25
AT±70±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTING
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A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTINGAT±71
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LOCATION OF CONNECTORS
AT0LA±02
Location of Connectors in Engine Compartment
AT±72±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTING
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Location of Connectors in Body
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A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTINGAT±73
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Location of Connectors in Instrument Panel
AT±74±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTING
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±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTINGAT±75
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J/B No. 1
AT±76±
A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTING
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±MEMO±
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A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTINGAT±77
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CIRCUIT INSPECTION
DTC42No. 1 Vehicle Speed Sensor Circuit
(Backup Sensor)
CIRCUIT DESCRIPTION
The No. 1 vehicle speed sensor outputs a 4±pulse signal for every revolu\
tion of the transmission output shaft.
After this signal is converted in to a more precise rectangular wave form by \
the wave form shaping circuit inside
the combination meter, it is then transmitted to the ECM.
DTC No.DTC Detecting ConditionTrouble Area
42
All conditions below are detected 500 times or ore con-
tinuously:
2 trip detection logic*
(a) No.1 vehicle speed sensor signal in 16 No 2 vehicle sensor signal
(b) Vehicle speed: 5.6 MPH (9km/h) or more for at least 4 secs. or more
(c) Park/neutral position switch: OFF (Other than P or N position)

No. 1 vehicle speed sensor.

Combination meter.

Harness or connector between No. 1 vehicle
speed sensor and ECM.

ECM
*: See page AT±62
Reference
Wave form between terminals SPD and E1 when vehicle speed is approx. 37 M\
PH (60km/h).
HINT: The greater the vehicle speed, the greater the number of SPD signals pro\
duced. AT±78
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A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTING
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WIRING DIAGRAM
combination meter
AT±66 combination meter
DIAGNOSTIC CHARTDIAGNOSTIC CHART
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A304E (1UZ±FE) AUTOMATIC TRANSMISSION TROUBLESHOOTINGAT±79
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