Electrical/Garage Shift Test

ELECTRICAL/GARAGE SHIFT TEST
This preliminary test should be performed before a hoist or road test to make sure electronic control inputs are connected and operating. If the inputs are not checked before operating the transaxle, a simple electrical condition could be misdiagnosed as a major transaxle condition.
A scan tool provides valuable information and must be used on the HYDRA-MATIC 4T40-E transaxle for accurate diagnosis.
1. Move gear selector to P (Park) and set the parking brake.
2. Connect scan tool to Data Link Connector (DLC) terminal.
3. Start engine.
4. Connect power to scan tool.
5. Verify that the appropriate signals are present. These signals may include:
- ENGINE SPEED
- TRANS INPUT SPEED
- TRANS OUTPUT SPEED
- VEHICLE SPEED
- TFP RANGE A/B/C
- PRNDL SELECT
- DESIRED PCS
- ACTUAL PCS
- PCS DUTY CYCLE
- BRAKE SWITCH
- ENG COOLANT TEMP
- TRANS FLUID TEMP
- THROTTLE ANGLE
- SYSTEM VOLTS
6. Monitor the BRAKE SWITCH signal while tapping the brake pedal with your foot.
- The BRAKE SWITCH should come on when the pedal is pressed, and turn off when the brake pedal is released.
7. Monitor the PRNDL SELECT signal and move the gear selector through all the ranges.
- Verify that the PRNDL SELECT value matches the gear range indicated on the instrument panel or console.
- Gear selections should be immediate and not harsh.
8. Move gear selector to neutral and monitor the THROTTLE ANGLE signal while increasing and decreasing engine RPM with the accelerator pedal. THROTTLE ANGLE should increase with engine RPM.