Perform this test before a hoist or road test
in order to make sure that electronic control inputs are connected and operating.
If you do not check the inputs before operating the transmission, you could
misdiagnose a simple electrical condition as a major transmission condition.
A scan tool provides valuable information. Usea scan tool on the Hydra-Matic
4T65-E transmission for accurate diagnosis.
- Move the gear selector to Park (P) and set the parking brake
- Connect the scan tool to the DLC teminal
- Start the engine
- Connect power to the scan tool
- Verify that the following signals are present on the scan tool:
- Monitor the BRAKE SWITCH signal while tapping the brake pedal
with your foot:
• | BRAKE SWITCH should be On when the pedal is depressed |
• | BRAKE SWITCH should be Off when the pedal is released |
- Monitor the PRNDL SELECT signal and move the gear selector through
all of the ranges:
• | Verify that the PRNDL SELECT value matches the rear range indicated
on the instrument panel or the console |
• | Gear selections should be immediate and not harsh |
- Move the gear selector to Neutral and monitor the TP ANGLE signal
while increasing and decreasing the engine RPM with the accelerator pedal.
TP ANGLE should increase with the engine RPM.