Scan Tool Data Definitions 4.3L

1-2 Shift Error: Displays a range of -6.38 to +6.38 seconds. This parameter is 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: Displays a range of 0.00-6.38 seconds. This parameter is the actual time of the last 1-2 shift. The shift time is based on the engine RPM drop after the commanded 1-2 shift. This value is only accurate if the shift was adaptable.

1-2 Sol: Displays On or Off. This parameter is the commanded status of the 1-2 shift solenoid 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).

1-2 Sol. Open/Short to GND: Displays Yes or No. This parameter indicates if an open or short to ground exists in the 1-2 shift solenoid valve feedback signal to the VCM. This parameter is valid only when the 1-2 shift solenoid is commanded Off.

1-2 Sol. Short to Volts: Displays Yes or No. This parameter indicates if a short to voltage exists in the 1-2 shift solenoid valve feedback signal to the VCM. This parameter is valid only when the 1-2 shift solenoid is commanded On.

1-2 TAP Cell (4-16): Displays kPa or psi. This parameter displays the amount of pressure varied from a calibrated base line pressure for shifts. Each TAP Cell is based on a calibrated shift torque value. Each TAP Cell value is calculated from the last shift time. This cell pressure is used in addition to calibrated base line pressure to adjust the apply of a clutch or band during the next shift.

2-3 Shift Error: Displays a range of -6.38 to +6.38 seconds. This parameter is 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: Displays a range of 0.00-6.38 seconds. This parameter is the actual time of the last 2-3 shift. The shift time is based on the engine RPM drop after the commanded 2-3 shift. This value is only accurate if the shift was adaptable.

2-3 Sol: Displays On or Off. This parameter is the commanded status of the 2-3 shift solenoid 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).

2-3 Sol. Open/Short to GND: Displays Yes or No. This parameter indicates if an open or short to ground exists in the 2-3 shift solenoid valve feedback signal to the VCM. This parameter is valid only when the 2-3 shift solenoid is commanded Off.

2-3 Sol. Short to Volts: Displays Yes or No. This parameter indicates if a short to voltage exists in the 2-3 shift solenoid valve feedback signal to the VCM. This parameter is valid only when the 2-3 shift solenoid is commanded On.

2-3 TAP Cell (4-16): See 1-2 TAP Cell (4-16).

3-2 Downshift Sol.: Displays On or Off. This parameter indicates if the 3-2 shift solenoid valve assembly is currently commanded On or Off. The solenoid commanded state is based on the transmission temperature. The solenoid will change states during a 3-2 downshift to regulate the appropriate pressure. The commanded state of the solenoid occurs at approximately 30 mph with a throttle increase.

3-2 Sol. Open/Short to GND: Displays Yes or No. This parameter indicates when an open or a short to ground exists in the 3-2 shift solenoid valve assembly feedback signal to the VCM. This parameter is valid only when the 3-2 shift solenoid is commanded Off.

3-2 Sol. Short to Volts: Displays Yes or No. This parameter indicates whether a short to voltage exists in the 3-2 shift solenoid valve assembly feedback signal to the VCM. This parameter is valid only when the 3-2 shift solenoid is commanded On.

3-4 Shift Error:  Displays a range of -6.38 to +6.38 seconds. This parameter is 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: Displays a range of 0.00-6.38 seconds. This parameter is the actual time of the last 3-4 shift. The shift time is based on the engine RPM drop after the commanded 3-4 shift. This value is only accurate if the shift was adaptable.

4WD: Displays Enabled or Disabled. This parameter indicates whether the vehicle is currently in a four-wheel drive mode.

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 (4WD Low requested). Disabled indicates a B+ voltage signal (4WD Low not requested).

A/C Clutch: Displays On or Off. This parameter indicates the commanded state of the A/C control relay. The clutch should be engaged when On displays.

Adaptable Shift: Displays Yes or No. Yes indicates that the proper operating conditions were all within the proper operating range during the last shift, and that the shift time was accurate. This shift information is then used through the adaptive function in order to update the adapt cells. No indicates that not all of the operating conditions were met in order to enable this function, and that the adapt cells were not updated.

Cruise: Displays Enabled or Disabled. This parameter indicates whether the VCM is allowing cruise operation. The VCM has the ability to disable cruise control under certain conditions.

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

Current TAP (Transmission Adaptive Pressure) Cell: Displays a TP cell range of 0-16. This parameter indicates the current throttle position cell used for line pressure modification (adaptation).

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 sensor. The engine coolant temperature is high (151°C/304°F) when the signal voltage is low (0 V), and the engine coolant temperature is low (-40°C/-40°F) when 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 how long the engine has been operating. When the ignition switch is turned OFF, the value is reset to zero.

Engine Speed: Displays a range of 0-8192 RPM. This parameter indicates the rotational speed of the engine expressed as revolutions per minute.

Engine Torque: Displays a range of 0-9999 lb ft. This parameter indicates the amount of torque that is delivered from the engine.

IAT (Intake Air Temperature): Displays a range of -40°C to 215°C (-40°F to 419°F). The IAT sensor is a thermistor that is used to monitor the temperature of the air entering the intake manifold. The VCM applies 5 volts to the sensor on a 5 volt reference circuit. When the air is cool, the resistance in the sensor will be high. If the air is warm, the sensor resistance will be low and the VCM will sense a low voltage signal. The VCM converts the signal of the IAT sensor to degrees Celsius. Intake air temperature is used by the VCM to adjust fuel delivery and spark timing.

Ignition Voltage: Displays a range of 0.0-25.5 V. This represents the system voltage measured by the VCM at its ignition feed.

Last TAP: Displays psi. This parameter indicates the amount of pressure that was added to base line pressure in order to adjust the apply effort of a clutch or a band during the last adapting shift.

PC Sol. Actual Current: Displays a range of 0.00-1.10 amps. This parameter is the actual current of the pressure control solenoid circuit at the control module. Zero amp (no current flow) indicates actual higher line pressure. Actual lower line pressure is indicated by 1.1 amps (high current flow).

PC Solenoid Duty Cycle: Displays a range of 0-100%. This parameter is the commanded state of the pressure control solenoid expressed as a percent of energized ON time. A reading of 0% indicates zero ON time (non-energized) or no current flow. Approximately 60% at idle indicates maximum ON time (energized) or high current flow.

PC Sol. Ref. (Reference) Current: Displays a range of 0.00-1.10 amps. This parameter is the commanded current of the pressure control solenoid circuit. Zero amp (no current flow) indicates commanded higher line pressure. Commanded lower line pressure is indicated by 1.1 amps (high current flow).

Speed Ratio: Displays a range of 0.00:1-8.00:1. This parameter indicates engine speed divided by transmission output speed. This value is used to estimate transmission gear ratio.

TCC (Torque Converter Clutch) Brake Switch: Displays Open or Closed. This parameter indicates the state of the brake switch circuit input. Open indicates a zero voltage input (brake switch open, brake pedal applied). Closed indicates a B+ voltage input (brake switch closed, brake pedal released).

TCC Duty Cycle: Displays a range of 0-100%. This parameter is the commanded percentage of ON time of the TCC PWM solenoid. Approximately 90% represents an ON (energized) commanded state. A reading of 0% represents an OFF (non-energized) commanded state. This commanded state is applied at a vehicle speed between approximately 0-16 km/h (0-10 mph).

TCC Duty Cycle Open/Short to GND: Displays Yes or No. This parameter indicates whether an open or a short to ground exists in the TCC PWM solenoid valve feedback signal to the VCM. This parameter is valid only when the TCC PWM solenoid is commanded OFF (duty cycle is 0%).

TCC Duty Cycle Short to Volts: Displays Yes or No. This parameter indicates whether a short to voltage exists in the TCC PWM solenoid valve feedback signal to the VCM. This parameter is valid only when the TCC PWM solenoid is commanded ON (duty cycle is at maximum).

TCC Enable: Displays Yes or No. This parameter is the commanded state of the TCC solenoid. Yes indicates a commanded energized state (current is flowing through the solenoid). No indicates a commanded non-energized state (current is not flowing through the solenoid). This commanded state occurs at various vehicle speeds between applications.

TCC Enable Open/Short to GND: Displays Yes or No. This parameter indicates whether an open or a short to ground exists in the TCC solenoid valve feedback signal to the VCM. This parameter is valid only when the TCC solenoid is commanded OFF.

TCC Enable Short to Volts: Displays Yes or No. This parameter indicates whether a short to voltage exists in the TCC solenoid valve feedback signal to the VCM. This parameter is valid only when the TCC solenoid is commanded ON.

TCC Mode: Displays a range of 0 through 5. Zero (0) or Off Mode indicates that the VCM commands the TCC OFF at a calibrated minimum throttle. The calibrated minimum throttle is different at low vehicle speeds than it is at high vehicle speeds. Off Mode is also active when the transmission is in the wrong gear range, the engine or the transmission is cold, the brake input indicates that the brakes are ON, a downshift or upshift is initiated, the engine is at idle, the transmission is in Hot Mode or a misfire is detected. One (1) or Release Mode indicates that the VCM commands the release of the TCC. Two (2) or Apply Mode indicates that the VCM commands the apply of the TCC. Apply pressure varies based on normal or performance operations, hot conditions or if the cruise control is active. Apply Mode is used under normal driving conditions. All apply pressure is dependent on throttle position and vehicle speed. Three (3) or Apply Enable Mode indicates that enabling conditions are met for applying the TCC (enabling conditions include vehicle speed, gear selection, transmission temperature, throttle angle, brake switch status, etc.). Four (4) or Locked Mode indicates that the VCM commands full capacity of the TCC when the transmission is in fourth gear and the vehicle speed is greater than a calibrated value. When variable TCC apply pressure stops (Apply Mode), maximum TCC pressure is used. Five (5) or Coast Mode indicates that the VCM commands apply of the TCC when the transmission is in fourth gear and the throttle and vehicle speed are not high enough to enable Apply Mode, but high enough to keep the TCC applied. When Coast Mode is active, TCC apply pressure is set to a predetermined amount.

TCC Slip Speed: Displays a range of -4080 to 4079 RPM. This parameter is the difference between transmission output speed and engine speed. A negative value indicates that the engine speed is less than the output speed (deceleration). A positive value indicates that the engine speed is greater than the output speed (acceleration). A value of zero indicates that the engine speed is equal to the output speed (TCC applied).

TFP Switch A/B/C: Displays On/Off, On/Off, On/Off. These parameters are 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.

TFT (Transmission Fluid Temperature) Sensor: Displays a range of 0.00-5.00 V. When the transmission fluid is cold, the sensor resistance is high and the VCM will sense high signal voltage. As the transmission fluid temperature warms to a normal operating temperature, the sensor resistance becomes less and the voltage decreases.

TP (Throttle Position) Angle: Displays a range of 0-100%. The TP angle is computed by the VCM from the TP sensor voltage. The TP angle should read 0% at idle and 100% at Wide Open Throttle (WOT).

TP (Throttle Position) Sensor: Displays a range of 0.00-5.00 V. The TP sensor is used by the VCM to determine the amount of throttle demanded by the driver. Voltage is below 1 volt at idle and above 4 volts at Wide Open Throttle (WOT).

Trans. Fluid Temp.: Displays a range of -40°C to 151°C (-40°F to 304°F). This parameter is the input signal of the transmission fluid temperature sensor. Transmission fluid temperature is high (151°C/304°F) when signal voltage is low (0 V), and transmission fluid temperature is low (-40°C/-40°F) when signal voltage is high (5 V).

Transmission Hot Mode: Displays ON or OFF. This parameter monitors transmission temperature. ON indicates that the transmission temperature has exceeded 135°C (275°F).

Transmission OSS (Output Shaft Speed): Displays a range of 0-8192 RPM. This parameter indicates the rotational speed of the transmission output shaft expressed as revolutions per minute.

Vehicle Speed: Displays a range of 0-255 km/h (0-158 mph). This parameter is the input signal from the vehicle speed sensor assembly.