Code 13 (No RPM Signal)
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 1990 Toyota Pickup, 1990 Toyota Cab & Chassis, 1990 Toyota 4Runner, 1989 Toyota Pickup, and 1989 Toyota Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
ECU will store trouble code No. 13 in memory if it does not receive signal "NE" pick-up coil (RPM) when engine speed is above 1000 RPM.