ATTE/A340 Automatic Trans (GTE) — Dtc 42 No.1 Vehicle Speed Sensor Signal Circuit, page 72

AT2–72
A340E (2JZ—GTE) AUTOMATIC TRANSMISSION – TROUBLESHOOTING

DTC 42 No.1 Vehicle Speed Sensor Signal Circuit

CIRCUIT DESCRIPTION

The No. 1 vehicle speed sensor outputs a 4–pulse signal for every revolution of the rotor shaft, which
is rotated by the transmission output shaft via the driven gear. After this signal is converted into a more
precise rectangular waveform by the waveform shaping circuit inside the combination meter, it is then
transmitted to the engine control module. The ECM determines the vehicle speed based on the fre-
quency of these pulse signals.

Transmission
Output Shaft

A/T    4-pulse    4-pulse    ECM

Rotor Shaft

No.1 Vehicle
Speed Sensor    Telltale Light
RH

Driven Gear

No.1 Vehicle Speed Sensor

FI6643 Q04361

DTC No.    Diagnostic Trouble Code Detection Condition    Trouble Area

42
All conditions below are detected for 4 secs. or
more. (2 trips detection logic)*
(a) No No.1 vehicle speed sensor signal in 16
    pulses of No.2 vehicle speed sensor signal.
(b) Vehicle speed: 9 km/h (5.6 mph) or more
(c) Park/neutral position switch:
    OFF (Other than P or N position)
No. 1 vehicle Speed sensor
Telltale light RH
Harness or connector between No. 1 vehicle
speed sensor and ECM
ECM

* See page AT2–58

HINT: In test mode, diagnostic trouble code 42 is output when vehicle speed is 5 km/h (3 mph) or
      below.

<Reference>
  Waveform between terminals SP1 and E2 when vehicle speed is approx. 20 km/h (12 mph).

HINT: As the vehicle's speed increases, the signal output from
      SP1 increases.

2 V/div

20 msec./division

V01495