4L80-E/4L85-E Automatic Transmission

Scan Tool Data Definitions

1-2 Shift Error
This parameter displays the difference between the desired 1-2 shift time and the actual 1-2 shift time. A positive number indicates a firm or fast shift, the actual shift time was shorter than the desired shift time. A negative number indicates a soft or slow shift, the actual shift time was longer than the desired shift time. This value is only accurate if the shift was adaptable.

1-2 Shift Time
This parameter displays the actual time of the last adaptable 1-2 shift. The shift time is based on the gear ratio change after the commanded 1-2 shift.

1-2 Sol.
This parameter displays the commanded state of the 1-2 shift solenoid valve. When the transmission is in FIRST and FOURTH gear, the display should indicate ON, current is flowing trough the solenoid. When the transmission is in SECOND and THIRD gear, the display should indicate OFF, current is not flowing through the solenoid.

1-2 Sol. Open/Short to GND
This parameter displays whether an open or a short to ground exists in the 1-2 shift solenoid valve feedback signal and displays Yes or No. The 1-2 shift solenoid valve must be commanded Off for this parameter to be valid.

1-2 Sol. Short to Volts
This parameter displays if a short to voltage exists in the 1-2 shift solenoid valve feedback signal. This parameter is valid only when the 1-2 shift solenoid valve is commanded ON. The scan tool will display YES or NO.

1-2 TAP Cell (4-16)
This parameter displays the amount of transmission adaptive pressure (TAP), based on 17 Nm (12.5 ft. lbs.) of engine torque increment per cell, added to or subtracted from shift pressure during a 1-2 upshift. A positive number indicates that long shifts have been detected and PC solenoid pressure has been added in order to decrease shift time. A negative number indicates that short shifts have been detected and PC solenoid pressure has been subtracted in order to increase shift time.

2-3 Shift Error
This parameter displays the difference between the desired 2-3 shift time and the actual 2-3 shift time. A positive number indicates a firm or fast shift, the actual shift time was shorter than the desired shift time. A negative number indicates a soft or slow shift, the actual shift time was longer than the desired shift time. This value is only accurate if the shift was adaptable.

2-3 Shift Time
This parameter displays the actual time of the last adaptable 2-3 shift. The shift time is based on the gear ratio change after the commanded 2-3 shift.

2-3 Sol.
This parameter displays the commanded state of the 2-3 shift solenoid valve. When the transmission is in FIRST and SECOND gear, the display should indicate OFF, current is not flowing trough the solenoid. When the transmission is in THIRD and FOURTH gear, the display should indicate ON, current is flowing through the solenoid.

2-3 Sol. Open/Short to GND
This parameter displays whether an open or a short to ground exists in the 2-3 shift solenoid valve feedback signal and displays Yes or No. The 2-3 shift solenoid valve must be commanded Off for this parameter to be valid.

2-3 Sol. Short to Volts
This parameter displays if a short to voltage exists in the 2-3 shift solenoid valve feedback signal. This parameter is valid only when the 2-3 shift solenoid valve is commanded ON. The scan tool will display YES or NO.

2-3 TAP Cell (4-16)
This parameter displays the amount of transmission adaptive pressure (TAP), based on 17 Nm (12.5 ft. lbs.) of engine torque increment per cell, added to or subtracted from shift pressure during a 2-3 upshift. A positive number indicates that long shifts have been detected and PC solenoid pressure has been added in order to decrease shift time. A negative number indicates that short shifts have been detected and PC solenoid pressure has been subtracted in order to increase shift time.

3-4 Shift Error
This parameter displays the difference between the desired 3-4 shift time and the actual 3-4 shift time. A positive number indicates a firm or fast shift, the actual shift time was shorter than the desired shift time. A negative number indicates a soft or slow shift, the actual shift time was longer than the desired shift time. This value is only accurate if the shift was adaptable.

3-4 Shift Time
This parameter displays the actual time of the last adaptable 3-4 shift. The shift time is based on the gear ratio change after the commanded 3-4 shift.

4WD
This parameter displays whether the vehicle is currently in a four-wheel drive mode. The scan tool displays Enabled or Disabled.

4WD Low
This parameter displays the signal state of the four-wheel drive low circuit. Enabled indicates a 0 voltage signal requesting 4WD low. Disabled indicates a B+ voltage signal which does not request 4WD low. The scan tool displays Enabled or Disabled.

A/C Clutch
This parameter displays the commanded state of the air conditioning(A/C) compressor clutch relay driver circuit and displays On or Off. The A/C compressor clutch should be engaged when On displays. When the display indicates On, the line pressure and the shift times will be adjusted for the additional engine load.

Commanded Gear
This parameter displays the current commanded state of the shift solenoid valves. The scan tool displays 1, 2, 3, 4 or 5.

Cruise
This parameter displays the commanded state of the cruise control system. The scan tool displays ENABLED or DISABLED. When the display indicates ENABLED, the PCM is allowing cruise control operation. When the display indicates DISABLED, the PCM has disabled cruise control operation. When the cruise control display is ENABLED, shift patterns will be altered for 2-3 and 3-4 upshifts or 4-3 and 3-2 downshifts.

Current TAP Cell
This parameter displays the current transmission adaptive pressure(TAP) cell in use for transmission line pressure adaptation. The cells are based on 17 Nm (12.5 ft. lbs.) of engine torque. The higher the engine torque, the higher the current TAP cell. The last cell used will remain displayed until the next adaptable upshift occurs.

ECT
This parameter displays the input signal from the engine coolant temperature (ECT) sensor. ECT is high at 151°C (304°F) when the signal voltage is low, 0 volt. ECT is low at -40°C (-40°F) when the signal voltage is high, 5 volt.

Engine Run Time
This parameter displays a measure in Hr:Min:Sec of the length of time the engine has been operating. When the ignition is cycled to OFF, the value is reset to zero.

Engine Speed
This parameter displays the rotational speed of the engine expressed as revolutions per minute.

Engine Torque
This parameter displays a calculated value based on engine load, throttle position, mass air flow, and other engine inputs. This parameter is accurate to within 20 Nm (15 ft. lbs.) of actual measured engine torque.

Gear Ratio
This parameter displays the actual transmission gear ratio. The scan tool displays the gear ratio calculated from the automatic transmission input shaft speed sensor(AT ISS) and the automatic transmission output shaft speed sensor(AT OSS) inputs.

Ignition Voltage
This parameter displays the system voltage measured at the ignition feed.

Last Shift Time
This parameter displays the actual time of the last upshift. This value is only accurate if the shift was adaptable.

PC Sol. Actual Current
This parameter displays the actual current flow through the pressure control solenoid circuit, which is measured by the control module. High current flow results in low line pressure. Low current flow results in high line pressure.

PC Sol. Ref. Current
This parameter displays the commanded current of the pressure control solenoid circuit. High current results in low line pressure. Low current results in high line pressure.

PC Solenoid Duty Cycle
This parameter displays the commanded state of the pressure control solenoid, expressed as a percentage of energized ON time. A reading of low percent indicates zero ON time, non energized, or no current flow. A high percent at idle indicates maximum ON time, energized, or high current flow.

Power Take-Off
This parameter displays when the Power Take-Off (PTO) is engaged. PTO mode disables all transmission diagnostics. The scan tool displays YES or NO.

Speed Ratio
This parameter displays the calculated speed ratio of the transmission. The ratio is calculated by dividing the output speed sensor signal by the input speed sensor signal. Gear ratio in a step-gear transmission is calculated in the opposite manner.

TCC Brake Switch
This parameter displays the status of the TCC brake switch circuit input. OPEN indicates a zero voltage input, brake pedal applied. CLOSED indicates a voltage input, brake pedal released. The scan tool displays OPEN or CLOSED.

TCC Duty Cycle
This parameter displays the commanded percentage of ON time for the TCC PWM solenoid. A high percentage represents an ON, energized, commanded state. 0 percent represents an OFF, non-energized, commanded state.

TCC Duty Cycle Open/Short to GND
This parameter displays whether an open or a short to ground exists in the TCC PWM solenoid valve feedback signal and displays Yes or No. The TCC PWM solenoid valve must be commanded Off for this parameter to be valid. The scan tool will display Yes only while the TCC PWM solenoid valve is Off. The display will pulsate.

TCC Duty Cycle Short to Volts
This parameter displays whether a short to voltage exists in the TCC PWM solenoid valve feedback signal and displays Yes or No. The TCC PWM solenoid valve must be commanded On for this parameter to be valid. The scan tool will display Yes only while the TCC PWM solenoid valve is On. The display will pulsate.

TCC Slip Speed
This parameter displays 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 greater than the input speed, acceleration. A value of zero indicates the engine speed is equal to the input speed, TCC applied.

TFP Sw.
This parameter displays Park/Neutral, Reverse, Drive4, Drive3, Drive2, Drive1 or invalid. This parameter is the decoded status of the three A/B/C inputs from the automatic transmission fluid pressure manual valve position switch. If a valid combination of inputs is not detected, invalid will be displayed.

TFP Sw. A/B/C
This parameter displays HI/LOW, HI/LOW, HI/LOW. This parameter indicates the status of the three inputs from the automatic transmission fluid pressure manual valve position switch assembly. LOW represents a zero voltage signal. HI represents an ignition voltage signal.

TFT Sensor
This parameter displays the voltage drop across the transmission fluid temperature (TFT) sensor circuit. 5 volts is applied to the TFT sensor circuit. The sensor is a thermistor which changes internal resistance based on temperature. When the sensor is cold, the internal resistance is high, resulting in a high signal voltage. As the sensor warms, the internal resistance decreases, and the signal voltage will also decrease. A low signal voltage indicates a warm TFT, and a high signal voltage indicates a cold TFT.

Tow/Haul Mode
This parameter displays when the transmission is operating in a towing or hauling mode. In tow/haul mode a different shift pattern is commanded that increases performance when towing or hauling. Shift quality and TCC scheduling are also affected during tow/haul mode operation. The scan tool displays Active or Inactive.

TP Indicated Angle
This parameter displays the desired throttle angle for operating conditions present at the time.

TR Sw.
This parameter displays the decoded status of the four A/B/C/P inputs from the transmission range switch. The scan tool displays Park, Reverse, Neutral, Drive, Intermediate, Low, and invalid. If a valid combination of inputs is not detected, invalid will be displayed.

TR Sw. A/B/C/P
This parameter displays the status of the four inputs from the transmission range switch. The scan tool displays HI/LOW. HI indicates an ignition voltage input to the control module. LOW indicates a zero voltage input to the control module.

Traction Control
This parameter displays Active or Inactive. When the PCM receives a request for torque reduction from the electronic brake traction control module (EBTCM), Active is displayed.

Trans. Fluid Temp.
This parameter displays the input signal of the transmission fluid temperature sensor. Transmission fluid temperature is high, 151°C (304°F), when signal voltage is low, 0 volt. Transmission fluid temperature is low, -40°C (-40°F ), when signal voltage is high, 5 volt.

Trans. Slip Counter
This parameter displays the number of times the P0894 diagnostic test has identified a slipping condition. This diagnostic test is required, to identify a slipping condition three times in a row in order to set the DTC P0894 Transmission Component Slipping diagnostic code. The scan tool displays 0, 1 or 2.

Transfer Case Ratio
This parameter displays the ratio of the transfer case, calculated by engine speed, divided by transmission output speed based on transmission commanded gear.

Transmission Hot Mode
This parameter displays the automatic transmission fluid temperature (TFT) and displays On or Off. Off indicates that the TFT has not exceeded 130°C (266°F). On indicates that the TFT has exceeded 130°C (266°F) and has not cooled to 120°C (248°F) for greater that 5 seconds. These numbers are approximate and differ with transmissions.

Transmission ISS
This parameter displays the rotational speed of the transmission input shaft. The scan tool displays input shaft speed as revolutions per minute (RPM).

Transmission OSS
This parameter displays the rotational speed of the transmission output shaft. The scan tool displays output shaft speed as revolutions per minute (RPM). On four-wheel drive applications, the transfer case output shaft speed is measured.

Turbine Speed
This parameter displays the rotational speed of the torque converter turbine shaft, and is expressed as revolutions per minute (RPM). In commanded gears 1, 2, and 3, the turbine speed equals the input speed. In commanded gear 4, the turbine speed equals � of the input speed.

Vehicle Speed
This parameter displays the speed at which the vehicle is traveling. The scan tool displays vehicle speed as kilometers per hour (km/h), miles per hour (MPH). The vehicle speed is calculated based on the input signal from the automatic transmission output shaft speed sensor.