Road Testing Vehicle
Road Testing VehicleNOTE: Always drive the vehicle in a safe manner according to driving conditions and obey all traffic laws.
The Shift Point Road Test and Torque Converter Clutch Operation Test provide diagnostic information on transaxle shift controls and torque converter operation.
Shift Point Road Test
This test verifies that the shift control system is operating correctly.
1. Bring engine and transaxle up to normal operating temperature.
2. Operate the vehicle with the selector lever in the D position (overdrive switch ON).
3. Apply minimum throttle and observe the speeds at which upshift occurs and torque converter engages.
Refer to the Shift Speeds Chart for the appropriate Final Drive Ratio (FDR).
4. Stop the vehicle. Select the D position (overdrive switch OFF). Repeat Step 3. The transaxle will make all upshifts except third to fourth and torque converter clutch apply should occur above 80 km/h (50 mph).
5. Press the accelerator pedal to the floor, Wide Open Throttle (WOT). The transaxle should shift from third to second, or third to first, depending on vehicle speed, and torque converter clutch should release.
6. With vehicle speed above 48 km/h (30 mph), move the transaxle range selector lever from D position to first position and release the accelerator pedal. The transaxle should immediately downshift to second gear. When vehicle speed drops below 32 km/h (20 mph), the transaxle should downshift into first gear.
7. If transaxle fails to upshift/downshift or torque converter clutch does not apply/release. REFER to Diagnosis by Symptom for possible causes. 4F27E Automatic Transaxle/Transmission
Torque Converter Diagnosis
Prior to installing a new torque converter, all diagnostic procedures must be followed. This is to prevent the unnecessary installation of new or remanufactured torque converters. Only after a complete diagnostic evaluation can the decision be made to install a new torque converter.
Begin with the normal diagnostic procedures as follows:
1. Preliminary Inspection.
2. Know and Understand the Customer Concern.
3. Verify the Concern - Carry out the Torque Converter Clutch Operation Test.
4. Carry out Diagnostic Procedures.
- Run on-board diagnostics.
- Repair all non-transaxle related DTCs first.
- Repair all transaxle DTCs.
- Rerun on-board diagnostic to verify repair.
- Carry out the Line Pressure Test. Line Pressure Test
- Carry out the Stall Speed Test. Stall Speed Test
- Carry out the Diagnosis by Symptom Index. 4F27E Automatic Transaxle/Transmission
- Use the index to locate the appropriate routine that best describes the symptom(s). The routine will list all possible components that may cause or contribute to the symptom. Check each component listed; diagnose and repair as necessary before replacing the torque converter.
Torque Converter Operations Test
This test verifies that the torque converter clutch control system and the torque converter are operating correctly.
1. Carry out the Quick Test. Check for DTCs. Refer to the Diagnostic Trouble Code Chart.
2. Connect a tachometer to the engine.
3. Bring the engine to normal operating temperature by driving the vehicle at highway speeds for approximately 15 minutes in O/D position.
4. After normal operating temperature is reached, maintain a constant vehicle speed of about 80 km/h (50 mph) and tap the brake pedal with the left foot.
5. The engine RPM should increase when brake pedal is tapped, and decrease about five seconds after pedal is released. If this does not occur, refer to Torque Converter Operation Concerns in the Diagnosis by Symptom Index.
6. If the vehicle stalls in O/D or manual 2 at idle with vehicle at a stop, move the position selector lever to manual 1 position. If the vehicle stalls, refer to Torque Converter Operation Concerns in the Diagnosis by Symptom section. Repair as necessary. If the vehicle does not stall in O/D position. REFER to Diagnosis by Symptom.