Electrical Function Check
- Connect scan tool. Ensure gearshift lever is in Park and parking brake is set. Start engine. Using scan tool, ensure the following data can be displayed and is functioning properly:
- Engine Speed
- Transmission Output Speed
- Vehicle Speed
- Transmission Range
- Commanded Gear (Current Gear)
- PC Solenoid Actual Current
- Brake Switch
- Engine Coolant Temperature
- Transmission Fluid Temperature
- Throttle Angle
- Ignition Voltage (Battery Voltage)
- 1-2 Shift Solenoid
- 2-3 Shift Solenoid
- TCC Solenoid
- TCC Slip Speed
- Band Apply Solenoid Duty Cycle
- Power Relay Status
- Shift Pattern (Econo/Sport)
- Default Mode
If all data is displayed and appears accurate, go to next step. If any data is in question, diagnose and repair as necessary. See HYDRA-MATIC 4L30-E ELECTRONIC CONTROLS article or SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
- Using scan tool, monitor brake switch signal while depressing and releasing brake pedal. Ensure scan tool displays CLOSED with brake pedal released and OPEN with brake pedal depressed.
- Apply brake pedal and set parking brake. Move gearshift lever from Park to Reverse, Reverse to Neutral, and then from Neutral to Drive. Pause 2-3 seconds in each range. Ensure engagements are immediate and not harsh.
- Using scan tool, monitor transmission range. Move gearshift lever through all ranges. Pause in each range for 2-3 seconds and return gearshift lever to Park. Ensure all gearshift lever positions match scan tool display.
- Using scan tool, monitor throttle angle while increasing and decreasing engine speed with accelerator pedal. Ensure actual engine speed matches engine speed displayed on scan tool.
- Record test results in question for reference and continue with road test.
NOTE:
Harsh engagement may be caused by high idle speed, commanded low PC solenoid current or default condition caused by DTCs. Soft or delayed engagements may be caused by low idle speed, low fluid level, commanded high PC solenoid current or cold fluid.