DTC 16, Vehicle Speed Signal Buffer Fault: Notes
Speed sensor circuit consists of a magnetic induction type sensor, a vehicle speed sensor buffer module and wiring. Gear teeth pressed on output shaft induce an alternating current in sensor. This signal is transmitted to buffer. Buffer compensates for various axle ratios and converts signal into a square wave for use by speedometer, cruise control, anti-lock brakes and PCM. Buffer sends 2 different signals to PCM.
Transmission output speed signal circuit relays transmission output speed which is used to control shift points, line pressure, TCC, DTC 24 and DTC 72. Vehicle speed signal circuit relays vehicle speed which is used to control engine operating functions and DTC 16. When DTC 24 or 72 is set, 2nd gear only at maximum line pressure will occur. DTC 16 will set when:
- Vehicle speed greater than 20 MPH.
- 1000-4400 RPM.
- Vehicle speed signal circuit is open or grounded.
- All conditions must be met for 2 seconds.
PCM will default to no cruise control or fuel cutoff.
- This tests for battery voltage at VSS buffer.
- This tests for proper ground path for vehicle speed sensor signal buffer.
- This tests for vehicle speed sensor signal buffer signal to PCM.
- This tests for a signal from VSS buffer to PCM.