Transmission Range Switch (Automatic Transmission)

On cars with automatic transmission, the display shows the selected transmission range with a line under the appropriate transmission symbol.

To get data on the transmission range, the control module measures battery positive voltage on pins 18, 19 and 20. Depending on the transmission range, the transmission range switch grounds these pins in different combinations as shown on the table.

Pin

18 19 20
Transmission range
P ON 0 V OFF 12 V OFF 12 V
R ON 0 V ON 0 V OFF 12 V
N OFF 12 V ON 0 V OFF 12 V
D OFF 12 V ON 0 V ON 0 V
3 ON 0 V ON 0 V ON 0 V
2 ON 0 V OFF 12 V ON 0 V
1 OFF 12 V OFF 12 V ON 0 V
Manual gearbox OFF 12 V OFF 12 V OFF 12 V

OFF 12 V = open circuit
ON 0 V = closed circuit