Diagnosis

True diagnosis of the automatic transaxle downshift system can only be performed during a road test. During the road test, while cruising in the "D" (DRIVE) range (2nd and 3rd gears), check to see that the 3-2 and 2-1 downshifts occur within the engine vacuum/vehicle speed limits detailed in the Transaxle Shift Schedule Diagram (Figure 2).


If downshifts occur, but not at the prescribed vehicle speeds, refer to Section 7A-1 of the 1990 or 1991 GEO Storm Service Manual for further transaxle diagnosis procedures.


If downshifts do not occur, perform the following diagnostic procedures:

1. Check fuse C-11 with a fuse tester. Replace as required.

2. Turn the ignition switch to "ON." Backprobe the kickdown switch connector with a J 340029-A digital multimeter from the BLK/YEL wire to a known good ground. Measure voltage.

If no voltage is present, repair open(s) in the BLK/YEL wire between the fuse block and the kickdown switch.

If voltage is present, proceed to step 3.

3. Slowly press the accelerator pedal down by hand until a clicking sound is heard from the kickdown switch.

^ If no click is heard, hold the accelerator pedal down and readjust the switch by loosening the locknut and rotating the switch in a clockwise direction until a click is heard. Rotate the switch an additional one-half turn clockwise past the point where the click was heard and retighten the locknut.

^ If a clicking sound can not be obtained by readjustment, replace the kickdown switch.

^ If a clicking sound is heard when the accelerator pedal approaches wide-open throttle, proceed to step 4.

4. Backprobe the kickdown switch connector with a J 34029-A digital multimeter from the BLU/WHT wire to a known good ground. Measure voltage with the accelerator pedal pressed to the wide-open throttle position.

^ If no voltage is present, replace the kickdown switch.

^ If voltage is present, proceed to step 5.

5. Backprobe the kickdown solenoid connector with a J 34029-A digital multimeter from the BLU/WHT wire to a known good ground. Measure voltage with the accelerator pressed to the wide-open throttle position.

^ If no voltage is present, repair open(s) in the BKU/WHT wire between the kickdown switch and the kickdown solenoid.

^ If voltage is present, proceed to step 6.

6. Remove the kickdown solenoid connector. Connect a J 34029 - A digital multimeter from the solenoid terminal to a known good ground. Measure resistance.

^ If resistance is not between 3.2 and 3.7 ohms, replace the kickdown solenoid.

^ If resistance is between 3.2 and 3.7 ghms, the automatic transaxle downshift system is operating correctly. Refer to Section 7A-1 of the 1990 or 1991 GEO Storm Service Manual for further transaxle diagnostic procedures.