Step by step ECU setup for 4L80E/4L85E transmission
The step by step instruction was built for 4L80E/4L85E transmissions wired as the diagram:
Enable Transmission Control Feature:
In Engine Settings – Map Options - check the boxes:
- Automatic Transmission Control
- Lockup control
- Gear change detection
In Sensors and Calibration - Inputs
- TPS – Calibrated – Input must be selected according with the engine wiring.
- Transmission Temperature – Default (GM USA)
- Brake Switch – Default – required only if “deactivate Lockup when brake pedal pressed” feature is desired and there is no brake pressure sensor.
- AT Range Selector – Switch A - Default
- AT Range Selector – Switch B - Default
- AT Range Selector – Switch C - Default
In Sensors and Calibration - Outputs
- Select outputs for the Transmission Solenoids (A and B), Blue or Gray outputs can be used. Select according with your available outputs.
- For Lockup solenoid and Line Pressure solenoid select Yellow Outputs.
Gear Change Detection:
In Sensors and Calibration – Gear change detection
- Information about the differential and gearbox for Gear Detection.
Automatic Transmission Range Selector (lever position):
In Sensors and Calibration – AT range selector
- The settings for the input from the lever position should be as bellow:
- The 4L80E/4L85E transmission sends to the ECU the same signal for Park and Neutral, so it’s the user's choice to select N or P instead.
Drive shaft RPM:
In Sensors and Calibration – Drive shaft RPM
- When using the 4L80E/4L85E transmission VSS, set 31 teeth and select your differential ratio and tire size info. Wheel speed sensor can be used instead.
Automatic Transmission Control:
In Other Functions – Automatic Transmission Control
- User preferences for transmission control settings.
In Other Functions – Automatic Transmission Control - Solenoids
- Solenoid A and B: 75Hz
- Line pressure solenoid: 293Hz for early versions and 614Hz for late (94 and up)
Gear change trigger table uses the same values for Upshift and Downshift:
In Other Functions – Automatic Transmission Control – Gear change trigger table
Gear Change Table:
In Other Functions – Automatic Transmission Control – Gear change table
- The values of the picture bellow are just a suggestion to start, do your own research and tell the ECU when to shift gears.
- Do not set the same speed for upshift and downshift for the same TPS position.
- The speed for upshift will always be higher than downshift, at least 2 miles/hour apart to avoid constantly gear shifting.
Gearbox Line Pressure Table:
In Other Functions – Automatic Transmission Control – Gear line pressure table
- This table is to adjust the Line pressure for smooth gear shifting and stable engine idle.
- Since the line pressure directly affects the torque converter, the adjustment is needed for a smooth run and will depend on the torque converter installed.
- Line pressure solenoids reduce the line pressure when activated, as so, if not using the output for controlling it, your 4L80E will apply full line pressure at all time.
- To reduce line pressure, you should increase the percentage of duty cycle on the solenoid. Values bellow are suggestive.
Line pressure by temperature compensation:
In Other Functions – Automatic Transmission Control – Line pressure by temperature compensation
- ATF’s density and viscosity drastically changes with temperature, that’s one of the reasons why using transmission temperature sensor is important to guarantee smooth operation. To reduce the pressure and maintain a smooth operation of your transmission system you should add more duty cycle on the solenoids, as showed:
Gear change line pressure:
In Other Functions – Automatic Transmission Control – Gear change line pressure compensation
- A momentary reduction of line pressure at the gear change, making even smoother gear changing. Suggestive values below.
In Other Functions – Lockup control
- For early versions of 4L80E the TCC (lockup) is ON/OFF solenoid, so PWM frequency can remain “0 Hz”. For late versions, with PWM TCC solenoid 32Hz for PWM frequency is recommended.
In Other Functions – Lockup control – Lockup table
- The Lockup Table should follow the same logic as the gear changing table, Lock-up speeds should be higher than Unlock speeds 2mph apart to avoid constantly locking and unlocking the converter.