Allison Automatic Transmission

ALLISON AUTOMATIC TRANSMISSION

Scan Tool Data Definitions

Cold Shift Pattern
Displays Enabled or Disabled. This parameter indicates whether the transmission is operating under a cold shift strategy.

Current Gear
Displays 1, 2, 3, 4, or 5. This parameter indicates the current commanded state of the shift solenoids.

Driver Demanded Engine Torque
Displays a range of 0-9,999 ft. lbs.). This parameter indicates the amount of torque that is requested by throttle angle and driving conditions.

ECT (Engine Coolant Temperature)
Displays a range of -40°C to +151°C (-40°F to +304°F). This parameter is the input signal of the engine coolant temperature (ECT) sensor. When the ECT is high (151°C), the signal voltage is low (0 V). When the ECT is low -40°C (-40°F), the signal voltage is high (5 V).

Engine Run Time
Displays a range of 0:00:00-18:12:15 hr/min/sec. This parameter measures the length of time the engine has been in operation during the present ignition cycle.

Engine Torque
Displays a range of 0-9,999 ft. lbs.). This parameter is a calculated value based on engine load, throttle position, mass air flow, and other engine and transmission inputs. This parameter is accurate to within (15 ft. lbs.) of actual measured engine torque.

Forced Motor Solenoid A Enabled
Displays Yes or No. This parameter indicates the commanded state of the pressure control solenoid A, reading Yes when the solenoid is energized and No when de-energized.

Forced Motor Solenoid B Enabled
Displays Yes or No. This parameter indicates the commanded state of the pressure control solenoid B, reading Yes when the solenoid is energized and No when de-energized.

Gear Commanded
Displays a range of 0-8. This parameter indicates the commanded gear state from the transmission control module (TCM). When the vehicle is in the Park or Neutral position this parameter displays 0. When the vehicle is placed in Drive, this parameter displays 1 while the vehicle is in first gear and changes accordingly as the vehicle shifts through 2, 3, 4, and 5.

Gear Ratio
Displays a range of 0.000 to 8.00:1. This parameter is the actual gear ratio of the current commanded gear. In the current gear of R, D4, D3, D2, D1, it is calculated by dividing the input speed by the output speed. In the current gear of D5, with TCC locked, the gear ratio is calculated by dividing the turbine speed by the output speed.

Gear Selected
Displays a range of 0-8. This parameter indicates the selected state of the gear selector. Park = 8, Reverse = 7, Neutral = 0, Drive = 5, 3 = 3, 2 =2, 1 =1 as the gear selector is moved through the ranges.

Ignition Voltage
Displays a range of 0.0-25.5 Volts. This parameter indicates the voltage level on the ignition input to the TCM. The normal ignition voltage is approximately 13.8 volts, but may vary between 11-16 volts.

Last Output Speed Range Shift
Displays a range of 0-8,192 RPM. This parameter indicates the RPM value at which the last shift occurred.

Next Output Speed for Downshift
Displays a range of 0-8,192 RPM. This parameter indicates the RPM value at which the next output speed downshift will occur based on current driving requirements.

Next Output Speed Upshift
Displays a range of 0-8,192 RPM. This parameter indicates the RPM value at which the next output speed upshift will occur based on current driving requirements.

Normal Shift Pattern
Displays Enabled or Disabled. This parameter indicates the transmission is operating under a normal shift pattern strategy.

PC Sol. A Actual Current
Displays 0.00-1.1 amps. This parameter is the actual current of the pressure control A solenoid circuit at the control module.

PC Sol. A Ref. Current
Displays 0.00-1.1 amps. This parameter is the commanded current of the pressure control A solenoid circuit at the control module.

PC Sol. B Actual Current
Displays 0.00-1.1 amps. This parameter is the actual current of the pressure control solenoid B circuit at the control module.

PC Sol. B Ref. Current
Displays 0.00-1.1 amps. This parameter is the commanded current of the pressure control solenoid B circuit at the control module.

PC Sol. A Duty Cycle
Displays 0-100 percent. This parameter is the commanded state of the pressure control A solenoid expressed as a percentage of energized On time.

PC Sol. B Duty Cycle
Displays 0-100 percent. This parameter is the commanded state of the pressure control solenoid B expressed as a percentage of energized On time.

Previous Gear
Displays 0-7. This parameter displays the most recent gear the transmission has completed. During an upshift or downshift it continues to display the gear it was currently in until the new gear position has been successfully completed.

Requested Torque
Displays a range of 0-9,999 ft. lbs.). This parameter indicates the amount of torque required by the driver.

Service Brake Status Inverted
Displays Enabled or Disabled. This parameter indicates the status of the brake switch. Enabled indicates that the brake pedal is not depressed. Disabled indicates that the brake pedal is depressed.

Shift Solenoid C
Displays On or Off. This parameter is the commanded state of the shift solenoid C valve. On represents a commanded energized state, current is flowing through the solenoid. Off represents a non-commanded state, current is not flowing through the solenoid.

Shift Solenoid D
Displays On or Off. This parameter is the commanded state of the shift solenoid D valve. On represents a commanded energized state, current is flowing through the solenoid. Off represents a non-commanded state, current is not flowing through the solenoid.

Shift Solenoid E
Displays On or Off. This parameter is the commanded state of the shift solenoid E valve. On represents a commanded energized state, current is flowing through the solenoid. Off represents a non-commanded state, current is not flowing through the solenoid.

Shift Solenoid C Open/Short to GND
Displays Yes or No. This parameter indicates if an open or a short to ground exists in the feedback signal from the shift solenoid C to the powertrain control module (PCM).

Shift Solenoid C Short to Volts
Displays Yes or No. This parameter indicates if a short to B+ exists in the feedback signal from the shift solenoid C to the PCM.

Shift Solenoid D Open/Short to GND
Displays Yes or No. This parameter indicates if an open or a short to ground exists in the feedback signal from the shift solenoid D to the PCM.

Shift Solenoid D Short to Volts
Displays Yes or No. This parameter indicates if a short to B+ exists in the feedback signal from the shift solenoid D to the PCM.

Shift Solenoid E Open/Short to GND
Displays Yes or No. This parameter indicates if an open or a short to ground exists in the feedback signal from the shift solenoid E to the PCM.

Shift Solenoid E Short to Volts
Displays Yes or No. This parameter indicates if a short to B+ exists in the feedback signal from the shift solenoid E to the PCM.

TCC Duty Cycle
Displays 0-100 percent. This parameter is the commanded percentage of On time the TCC solenoid is energized. 90 percent represents an On, energized, commanded state. 0 percent represents an Off, non-energized, commanded state.

TCC Duty Cycle Open/Short to GND
Displays Yes or No. This parameter indicates if an open or a short to ground exits in the feedback signal from the TCC solenoid valve to the PCM.

TCC Duty Cycle Short to Volts
Displays Yes or No. This parameter indicates if a short to B+ exits in the feedback signal from the TCC solenoid valve to the PCM.

TCC Slip Speed
Displays -4,080 to +4,079 RPM. This parameter is the difference between transmission input speed and engine speed. A negative value indicates the engine speed is less than the input speed, deceleration. A positive value indicates the engine speed is equal to the input speed, TCC applied.

TFP Sw. C/D/E/R
Displays On/Off, On/Off, On/Off. This parameter indicates the state of the three inputs from the automatic transmission fluid pressure manual valve position switch assembly. On represents a 0 voltage signal. Off represents a B+ voltage signal.

Torque Management Duty Cycle
Displays in a percent of Duty Cycle. This parameter indicates the amount of torque management being used by the transmission control module (TCM).

Tow/Haul Mode
Displays Active/Inactive. This parameter indicates whether the driver has placed the vehicle in the Tow/Haul mode. When this parameter is active, the TCM modifies the shift strategy in order to provide more torque to the wheels during shifts.

Torque Requested
Displays a range of 0-9,999 ft. lbs.). This parameter indicates the amount of torque required by the driver.

TP Angle
Displays a range of 0-100 percent. The TP angle is computed by the PCM, from TP voltage. The TP angle should display 0 percent at idle and 100 percent at wide open throttle (WOT).

TR Sw.
Displays a range of Park, Reverse, Neutral, Drive, 4, 3, 2, 1. The transmission range (TR) switch indicates the TR selected by the driver.

TR Sw. A/B/C/P
Displays On/Off, On/Off, On/Off, On/Off. These parameters are the four inputs from the automatic transmission fluid pressure manual valve position switch assembly. ON represents a 0 voltage signal. OFF represents a B+ voltage signal.

Trans. Fluid Temp.
Displays -40°C to +151°C (-40°F to +304°F). This parameter is the input signal of the transmission fluid temperature sensor. The transmission fluid temperature is high when the signal voltage is low, 0 volts, and transmission fluid temperature is low when the signal voltage is high, 5 volts.

Transmission Hot Mode
Displays On or Off. This parameter monitors the transmission fluid temperature (TFT). Yes indicates the transmission fluid temperature has exceeded 135°C (275°F).

Transmission ISS
Displays 0-8,192 RPM. This parameter measures the rotational speed of the input shaft expressed as revolutions per minute (RPM).

Transmission OSS
Displays 0-8,192 RPM. This parameter measures the rotational speed of the transmission output shaft expressed as RPM. On four-wheel drive applications, the transfer case output shaft speed is measured.

Turbine Speed
Displays 0-8,192 RPM. This parameter indicates the rotational speed of the torque convertor turbine shaft expressed as RPM. In commanded gears 1, 2, 3, and 4, the turbine speed equals the input speed.

4WD Low
Displays Enabled or Disabled. This parameter is the signal state of the four-wheel drive low circuit. Enabled indicates a 0 voltage signal requested 4WD low. Disabled indicates a B+ voltage signal, which does not request 4WD low.