Quick Check
- Check level and condition of transaxle fluid. Check PCM memory for stored codes. See AUTO TRANS DIAGNOSIS - HYDRA-MATIC 4T80-E CONTROLS - 1995 article or AUTO TRANS DIAGNOSIS - HYDRA-MATIC 4T80-E CONTROLS - 1996 article. If no codes are present, go to next step. If codes are present, diagnose and repair all PCM-related codes. Clear PCM code memory.
- Perform road test. See ROAD TEST under TESTING. Enter PCM data mode to monitor throttle angle. See appropriate 4T80-E ELECTRONIC CONTROLS article. During road test, record shift points. If shift point timing or shifting is incorrect, go to appropriate 4T80-E ELECTRONIC CONTROLS article.
- If shift(s) is too harsh or too soft, see HYDRAULIC PRESSURE TESTS under TESTING.
- For specific complaints, see appropriate condition(s) listed under SYMPTOMS in TROUBLE SHOOTING.