Lexus SC300 / Lexus SC400. Service manual - part 80

J/B No. 1

AT–76

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A304E (1UZ–FE) AUTOMATIC TRANSMISSION

TROUBLESHOOTING

–MEMO–

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A304E (1UZ–FE) AUTOMATIC TRANSMISSION

TROUBLESHOOTING

AT–77

CIRCUIT INSPECTION

DTC

42

No. 1 Vehicle Speed Sensor Circuit 
(Backup Sensor)

CIRCUIT DESCRIPTION

The No. 1 vehicle speed sensor outputs a 4–pulse signal for every revolution 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 Condition

Trouble 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 MPH (60km/h).

HINT: The greater the vehicle speed, the greater the number of SPD signals produced.

AT–78

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A304E (1UZ–FE) AUTOMATIC TRANSMISSION

TROUBLESHOOTING

WIRING DIAGRAM

combination meter

AT–66

combination meter

DIAGNOSTIC CHART

DIAGNOSTIC CHART

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A304E (1UZ–FE) AUTOMATIC TRANSMISSION

TROUBLESHOOTING

AT–79