Shift Point Road Test
Road Testing the VehicleNOTE: Always drive the vehicle in a safe manner according to driving conditions and obey all traffic laws.
The following tests provide diagnostic information on transmission shift controls and torque converter operation.
Refer to Component Tests for Torque Converter Diagnosis. [1][2]Component Tests
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 transaxle range selector lever in D position.
3. Apply minimum throttle and observe speeds at which upshift occurs and torque converter engages. Refer to Shift Speeds Chart. Also refer to the Automatic Transmission specifications.
CAUTION: Do NOT EXCEED POSTED SPEED LIMITS when carrying out this test.
Shift Speed Chart
4. Coasting 2-1 downshift procedure: Accelerate vehicle from a stop to 19 - 24 km/h (12 - 15 mph). Backout and coast down or lightly brake the vehicle. The coast downshift may be nearly imperceptible to the driver.
5. With the vehicle in D (fourth gear), depress the transmission control switch. The transaxle should downshift to third gear. Remove foot from accelerator pedal; engine braking should occur. The torque converter clutch should disengage and then reapply.
6. Depress the accelerator pedal to floor. The transaxle should shift from third to second gear, or third to first, depending on vehicle speed.
7. With vehicle in D range above 80 km/h (50 mph) and less than half throttle, move the transaxle range selector lever from D range to manual 2 range and remove foot from accelerator pedal. The transaxle should immediately downshift into second gear. With the vehicle remaining in manual 2 range, move the transaxle range selector lever into manual 1 range and release the accelerator pedal. The transaxle should downshift into first gear at speeds below 48 - 56 km/h (28 - 32 mph).
NOTE: Shift speed ranges are approximate for all applications. For specific applications (engine, axle ratio and application) refer to the product guide.
8. If the transaxle fails to upshift/downshift or the torque converter does not apply and release, refer to the procedure. Refer to Diagnosis By Symptom for possible causes.
Torque Converter Diagnosis
Prior to torque converter replacement, all diagnostic procedures must be followed. This is to prevent the unnecessary replacement of good torque converters. Only after a complete diagnostic evaluation can the decision be made to replace the torque converter.
Begin with the normal diagnostic procedures as follows:
9. Preliminary Inspection
10. Know and Understand the Customers Concern.
11. Verify the Concern
- Carry out the Torque Converter Clutch Operation Test.
12. Carry out Diagnostic Procedures
- Run On-Board Diagnostics.
- Repair all non-transmission related DTCs first.
- Repair all transmission DTCs.
- Rerun on-board diagnostics to verify repair.
- Carry out Line Pressure Test.
- Carry out Stall Speed Test.
- Carry out Diagnosis by Symptom Routines.
- 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 required, before repairing the torque converter.
Torque Converter Clutch Operation Test
This test verifies that the torque converter clutch control system and the torque converter are operating correctly. Carry out the test as follows:
13. Carry out on-board diagnostic test. Refer to appropriate pinpoint test or procedure for diagnosis.
14. Connect a tachometer to the engine.
15. Bring engine to normal operating temperature by driving the vehicle at highway speeds for approximately 15 minutes in D position.
16. After normal operating temperatures are reached, maintain a constant vehicle speed of about 80 km/h (50 mph) and tap the brake pedal with the left foot.
17. Engine rpm should increase when the brake pedal is tapped, and should decrease about five seconds after the brake pedal is released. If this does not occur, refer to torque converter operation concerns. Refer to Torque Converter Operation Concerns in Diagnosis By Symptom.
18. If the vehicle is at a stop and stalls in D at idle, move the transaxle range selector lever to the manual 1 position. Refer to Torque Converter Operation Concerns in Diagnosis By Symptom. Repair as required. If the vehicle does not stall in manual 1, refer to the procedure. Refer to Torque Converter Operation Concerns in Diagnosis By Symptom.