Action Taken

WARNING: This page is about a different car, the 1990 Cadillac Fleetwood and 1990 Cadillac DeVille. However, it is still accessible from the selected car via links, so may be relevant.

ECM turns on SERVICE SOON light.
Disable VCC and cruise for entire key cycle.

The speed sensor generates an electrical signal representative of vehicle speed. The vehicle speed sensor buffer amplifies and conditions signal from speed sensor to ECM. Code E24 indicates that a speed signal is not being received by ECM.

NOTE: Test numbers refer to test numbers on diagnostic chart.

Test Number 1) Vehicle speed sensor provides a 0-36 volt AC signal to ECM depending on vehicle speed. With tires moving, signal to ECM should be greater than .5 volt AC.