With EATX (Electronic Automatic Transmission Controller)

NAME OF CODE
No Vehicle Speed Sensor Signal

WHEN MONITORED
With the engine running more than 31 seconds, engine temperature greater than 120° F, transmission not in park or neutral, brakes not applied, engine rpm greater than 1800, and MAP vacuum less than 11".

SET CONDITION
No signal from the vehicle speed sensor (TCM) is present for more than 11 seconds.

THEORY OF OPERATION
The vehicle speed sensor signal is provided to the PCM by the TCM, The signal is calculated by the TCM based on the output speed sensor signal and the speedometer pinion factor, The PCM provides a 5-volt pull-up signal from cavity 66 to TCM cavity 58. The sensor signal is created by the TCM alternating the signal from 5V to 0.3V.

POSSIBLE CAUSES
- Open or shorted signal circuit
- Speedometer pinion factor not programmed
- Output speed sensor circuit problem
- Failed PCM
- Failed TCM