ATGE/A340 Automatic Trans (GE) — Dtc 42 No. 1 Vehicle Speed Sensor Signal Circuit, page 66

AT1–66
AT340E (2JZ–GE) 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 ECM. The ECM determines the vehicle speed based on the frequency of these pulse signals.

A/T    4-pulse    4-pulse    ECM
No.1 Vehicle Speed Sensor    Telltale Light RH

Driven Gear
Drive Gear
Transmission Output Shaft
No.1 Vehicle Speed Sensor

FI6643 FI6644

DTC No. | Diagnostic Trouble Code Detection Condition | Trouble Area

42
All conditions below are detected 500 times or more continuously. (2 trip 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 for 4 secs. or more for 4 secs. 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 AT1–54

HINT: In test more, 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).

2 V/div
20 msec./division

V01496

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