I. Code E39

1. VCC must be commanded on - the VCC status light on.
2. 4th gear - 4th gear status light on.
3. Closed loop operation - status light on.
4. Throttle applied (throttle switch open) - status light off.
5. Brake not applied - brake switch closed.
6. Gear selector must be in a drive range.

NOTE: Diagnostic status lights can be used to make sure the car is in the testing condition, however, a code cannot set while in diagnostics. Code E39 will usually be displayed as a history code because of the test conditions that must be met. The code IS NOT considered intermittent if it is stored as a history code.

Once the above test conditions are met, a Code E39 will set when the ECM detects that engine speed (rpm) is greater than expected for a given vehicle speed (mph). The ECM compares the actual engine speed and vehicle speed values to the expected rpm and mph values in the ECM PROM. If the actual engine rpm is higher than the value programmed into the ECM PROM for at least 10 seconds on 1985-1987 vehicles or at least five seconds on 1988-1989 vehicles, the ECM will set a Code E39.





Some example values are shown in Figure 1 for 1985-1989 Cadillacs. If rpm is greater than the value listed in Figure 1 at the corresponding mph for at least 10 seconds on 1985-1987 vehicles or at least five seconds on 1988-1989 vehicles, a Code 39 will set.