With EATX (Electronic Automatic Transmission Controller)

NAME OF CODE:
No Vehicle Speed Sensor Signal

WHEN MONITORED:
With 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 (VSS) 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 supplies a 5 volt pull up voltage 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
- Open vehicle speed sensor circuit
- PCM failure
- TCM failure