This list explains each data message displayed on the Tech 1 scan tool.

This information will assist you in tracking down emissions or driveability DTCs, because you can view the displays while you are driving the vehicle. Refer to the On-Board Diagnostic System Check in Section 6E for additional information.

1-2 Accum. High: Range, -128 to +127 psi. This display indicates a value which is used to determine the amount of modification to the high shift torque 1-2 adapt.

1-2 Accum. Low: Range, -128 to +127 psi. This display indicates a value which is used to determine the amount of modification to the low shift torque 1-2 adapt.

1-2 DES WOT (1-2 Desired Wide Open Throttle): Range, 0-6553. This display indicates the desired maximum engine speed obtained during a 1-2 upshift at wide open throttle.

1-2 DES WOT TAP (1-2 Desired Wide Open Throttle Transmission Adapt Pressure): Range, -16 to +15 mph. This display indicates a mph offset which is used to modify the wide open throttle 1-2 shift point to achieve the desired 1-2 wide open throttle RPM.

1-2 Shift Error: Range, -3.20 to +3.18 seconds. This display is the difference between the desired 1-2 shift time and the actual 1-2 shift time. The greater the negative number equals a longer shift.

1-2 Shift Time: Range, 0.00-6.38 seconds. This display is the actual time of the last 1-2 shift. The shift time is based on a gear box ratio change after the commanded 1-2 shift.

1-2 Sol (Solenoid) 2-3 Sol (Solenoid): Displays On or Off. When the transmission is in first and fourth gear, the display should indicate ON for the 1-2 solenoid. When the transmission is in second and third gear, the display should indicate OFF for the 1-2 solenoid. When the transmission is in first and second gear, the display should indicate OFF for the 2-3 solenoid. When the transmission is in third and fourth gear, the display should indicate ON for the 2-3 solenoid.

1-2 TAP High (1-2 Shift Transmission Adapt Pressure High): Range -32 to +31 psi. This display is the amount of pressure that is added to the base line pressure in order to adjust the holding effort of a clutch or a band during a 1-2 shift with high shift torque.

1-2 TAP Low (1-2 Shift Transmission Adapt Pressure Low): Range -32 to +31 psi. This display is the amount of pressure that is added to the base line pressure in order to adjust the holding effort of a clutch or a band during a 1-2 shift with low shift torque.

2-1 Shift Time: Range, 0.00-6.38 seconds. This display is the actual time of the last 2-1 shift. The shift time is based on a gear box ratio change after the commanded 2-1 downshift.

2-3 Accum. High: Range -128 to +127 psi. This display indicates a value which is used to determine the amount of modification to the high shift torque 2-3 adapt.

2-3 Accum. Low: Range -128 to +127 psi. This display indicates a value which is used to determine the amount of modification to the low shift torque 2-3 adapt.

2-3 Shift Error: Range, -3.20 to +3.18 seconds. This display is the difference between the desired 2-3 shift time and the actual 2-3 shift time. The greater the negative number equals a longer shift.

2-3 Shift time: Range, 0.00-6.38 seconds. This display is the actual time of the last 2-3 shift. The shift time is based on a gear box ratio change after the commanded 2-3 shift.

2-3 TAP High (2-3 Shift Transmission Adapt Pressure High): Range -32 to +31 psi. This display is the amount of pressure that is added to the base line pressure in order to adjust the holding effort of a clutch or a band during a 2-3 shift with high shift torque.

2-3 TAP Low (2-3 Shift Transmission Adapt Pressure Low): Range -32 to +31 psi. This display is the amount of pressure that is added to the base line pressure in order to adjust the holding effort of a clutch or a band during a 2-3 shift with low shift torque.

3-2 Shift Time: Range, 0.00-6.38 seconds. This display is the actual time of the last 3-2 shift. The shift time is based on a gear box ratio change after the commanded 3-2 downshift.

3-4 Accum. High: Range -128 to +127 psi. This display indicates a value which is used to determine the amount of modification to the high shift torque 3-4 adapt.

3-4 Accum. Low: Range -128 to +127 psi. This display indicates a value which is used to determine the amount of modification to the low shift torque 3-4 adapt.

3-4 Shift Error: Range -3.20 to +3.18 seconds. This display is the difference between the desired 3-4 shift time and the actual 3-4 shift time. The greater the negative number equals a longer shift.

3-4 Shift Time: Range, 0.00-6.38 seconds. This display is the actual time of the last 3-4 shift. The shift time is based on a gear box ratio change after the commanded 3-4 shift.

3-4 TAP High (3-4 Shift Transmission Adapt Pressure High): Range -32 to +31 psi. This display is the amount of pressure that is added to the base line pressure in order to adjust the holding effort of a clutch or a band during a 3-4 shift with high shift torque.

3-4 TAP Low (3-4 Shift Transmission Adapt Pressure Low): Range -32 to +31 psi. This display is the amount of pressure that is added to the base line pressure in order to adjust the holding effort of a clutch or a band during a 3-4 shift with low shift torque.

4-3 Shift Time: Range 0.00-6.38 seconds. This display is the actual time of the last 4-3 shift. The shift time is based on a gear box ratio change after the commanded 4-3 downshift. A value of zero indicates engine RPM is equal to output shaft RPM (TCC applied).

A/C Relay: Displays On or Off. This represents the commanded state of the A/C clutch control relay. The clutch should be engaged whenever ON is displayed. The PCM will compensate for the additional engine load that is accompanied with the A/C clutch engaged.

Active Trans. DTC: Range 0-255. This display will show active Diagnostic Trouble Codes (DCTs) which are stored in Freeze Frame and Failure Record.

Adaptable Shift: Displays Yes or No. This display is the monitor of the upshift adapt function. When the adapt capability is functional, YES will be displayed during shift calculation and until the commanded gear changes. When the adapt function is not functional, NO will be displayed.

Barometric Pressure Sensor (BARO): Range 10-104 kPa, 0.0-5.0V. The MAP sensor is used to measure barometric pressure when the ignition is turned to the run position and during Wide Open Throttle (WOT). The PCM will make adjustments for fuel delivery, ignition timing, line pressure and shift times for changes in altitudes.

Cruise Engaged: Displays Yes or No. When the display indicates YES, the PCM is allowing cruise control operation. When the display indicates NO, the PCM has disabled cruise control operation. When the cruise control display is YES, shift patterns will be altered for 2-3 and 3-4 upshifts or 4-3 and 3-2 downshifts.

Current Gear: Range, 1,2,3,4. This display indicates the current commanded state of the shift solenoids.

Delivered Torque: Range 0-100%. This is a calculated torque output from the engine to the transmission which is used by the Electronic Brake Traction Control Module (EBTCM) for traction control system operation. The PCM will use this information for line pressure control.

Desired Idle: Range 0-2040 RPM. This display will show engine idle speed that is commanded by the PCM. The PCM will compensate for various engine loads and temperatures to keep the engine at the desired idle speed.

DS In Progress (Down Shift): Displays Yes or No. This display indicates when the transmission is currently in a downshift. YES indicates a downshift is in progress. NO indicates a downshift is not in progress.

ECT (Engine Coolant Temperature): Range -40 to 151°C and -40 to 304°F. This display is the temperature conversion of the voltage input signal to the PCM of the engine coolant temperature.

ECT Sensor (Engine Coolant Temperature Sensor): Range 0.0-5.0V. This display shows the actual voltage drop across the PCM's internal resistors and the Engine Coolant Temperature Sensor. The Engine coolant temperature is high (151°C) when the signal voltage is low (0V) and the engine coolant temperature is low (-40°C) when the signal voltage is high (5.1V).

Engine Load: Range 0-100%. The engine load is calculated by the PCM from the engine speed and mass airflow. The engine load should increase with an increase in engine RPM and airflow.

Engine Run time: Displays Hours/Minutes/Seconds. This display will show how long the engine has been running. When the ignition is turned OFF, the timer is reset to zero.

Engine Speed (RPM): Range 0-9999 RPM. Engine speed is computed by the PCM from the fuel control reference input (crankshaft position sensor). This parameter indicates the rotational speed of the engine expressed as revolutions per minute.

Engine Torque: Range 0-510 N·m. This display indicates the amount of torque that is delivered from the engine.

Gear Box Torque: Range 0-510 N·m. This display indicates the amount of torque that is delivered to the transmission turbine shaft. This value reflects the torque multiplication through the torque converter.

Gear Ratio:  Range 0.00-4.00. This display is the actual transmission gear ratio as the transmission operates through all drive ranges including reverse and Park/Neutral. If the display indicates an unfamiliar gear ratio in park or neutral, this ratio will be the average ratio for all gears at the end of the drive cycle.

GSTAP Act. (Garage Shift Transmission Adapt Pressure Time Actual): Range -5120 to +5080. This display indicates the garage shift pressure pulse adapt time in use for the current garage shift.

GSTAP D4 High (Garage Shift Transmission Adapt Pressure): Range -3.20 to +3.17 seconds. This display indicates the garage shift pressure pulse adapt time. These ranges are in association with high transmission temperature garage shifts into drive 4.

GSTAP D4 Low (Garage Shift Transmission Adapt Pressure): Range -3.20 to +3.17 seconds. This display indicates the garage shift pressure pulse adapt time. These ranges are in association with low transmission temperature garage shifts into drive 4.

GSTAP Rev High (Garage Shift Transmission Adapt Pressure Reverse): Range -3.20 to +3.17 seconds. This display indicates the garage shift pressure pulse adapt time. These ranges are in association with high transmission temperature garage shifts into reverse.

GSTAP Rev Low (Garage Shift Transmission Adapt Pressure Reverse): Range -3.20 to +3.17 seconds. This display indicates the garage shift pressure pulse adapt time. These ranges are in association with low transmission temperature garage shifts into reverse.

GSTAP Shift (Garage Shift Transmission Adapt Pressure Time): Displays Yes or No. This display indicates that the PCM is adapting the time that the fill pressure pulse is issued when a Park/Neutral to Drive/Reverse garage shift occurs. The adapt capability is functional when YES is displayed. When NO is displayed, the adapt capability is nonfunctional.

Hot Mode: Displays Yes or No. This display indicates transmission hot mode operation due to high transmission fluid temperature. NO indicates that the transmission fluid temperature has not exceeded 130°C (266°F). YES indicates that the transmission fluid temperature has exceeded 130°C (266°F) and has not cooled to 120°C (248°F) for more than five seconds.

Ignition 0: Range 0.0-25.5V. This represents the system voltage measured by the PCM at its ignition input when the ignition is in the run position.

Ignition 1: Range 0.0-25.5V. This represents the system voltage measured by the PCM at its ignition input.

Intake Air Temperature (IAT): Range -40 to 215°C (-40 to 419°F). The changes in air temperature will cause a change in voltage across the sensor. The PCM calculates this voltage to air temperature as it enters the intake manifold. The IAT sensor is used by the PCM to adjust fuel delivery, ignition timing, line pressure, and shift timing.

Latest Shift: Range 0.00-6.38 seconds. This display indicates the actual shift time of the last upshift.

Latest Shift Err: Range -3.20 to +3.18 seconds. This display is the difference between the latest desired shift time and the latest actual shift time. The greater the negative number equals a longer shift.

Manifold Absolute Pressure (MAP): Range 10-104 kPa, 0.00-5.0V. The MAP sensor measures changes in the intake manifold pressure which is a result from engine RPM and engine load changes. The PCM uses this information to adjust fuel delivery and ignition timing.

Mass Air Flow (MAF): Range 0-655 g/s. The PCM converts the mass air flow sensor input signal into grams per second. This indicates the amount of air flow entering the intake manifold. The PCM uses this information to adjust transmission line pressure.

MPH (Miles per Hour): Range 0-158 mph, 0-255 km/h. the vehicle speed sensor input is converted by the PCM to be displayed in mph and km/h.

Odometer: Range 0-993474 miles. This display is the actual vehicle miles stored within the PCM.

Outside Air Temp: Range -40 to 101°C (-40 to 214°F). This is the outside temperature which is sent from the HVAC to the PCM via serial data.

PC ACT. Current (Pressure Control Actual Current): Range 0.0-1.25 amps. This display is the actual current flow through the pressure control solenoid circuit which is monitored by the PCM. High line pressure indicates low current. Low line pressure indicates high current flow.

PC Cur. Error (Pressure Control Current Error): Range 0.00-4.98 amps. This display is the difference between the PC Reference current to the Pressure Control Solenoid and the PC Actual current through the Pressure Control Solenoid circuit.

PC Duty (Pressure Control) Cycle: Range 0-100%. This display indicates the commanded state of the pressure control solenoid expressed as a percent of ON time (energized). No current flow indicates zero ON time or 0% duty cycle. High current flow is approximately 60% duty cycle at idle.

PC Pressure (Pressure Control Pressure): Range 0-255 psi. This display is a calculated line pressure that is commanded by the PCM.

PC Ref. Current (Pressure Control Reference Current): Range 0.0-1.25 amps. This display is the amount of current which the PCM has commanded through the pressure control solenoid circuit. High line pressure indicates low current flow. Low line pressure indicates high current flow.

Power Enrichment: Displays Inactive or Active. This display will show ACTIVE when acceleration is moderate to heavy.

Shift Adapt Pres: Range -64 to +64 psi. This display indicates the amount of pressure added to the base line pressure to adjust the holding effort of a clutch or a band during a shift.

Shift Completed: Displays Yes or No. This display indicates when the transmission has completed a shift. YES indicates that the shift is complete. NO indicates that the shift is incomplete.

Shift Delay: Range 0.00-6.38 seconds. This display indicates the time delay between the time a shift is commanded and the time the gear box ratio begins to change.

Shift Mode Sw: Displays Active or Inactive. This display shows the actual state of the performance control program within the PCM. The display indicates INACTIVE when the performance mode is not active (normal shift pattern). The display indicates ACTIVE when the performance mode is active (performance shift pattern).

Shift Pres. Err (Shift Pressure Error): Range -128 to +127 psi. This display indicates a calculated amount of pressure needed to correct the measured shift time error for the next shift.

Shift Press.: Range 0-255 psi. This display is the commanded line pressure value as determined by the PCM.

Shift Speed: Range 0-6553 RPM. This display indicates the maximum engine speed obtained during an upshift.

Shift Started: Displays Yes or No. This display indicates when the PCM has commanded a shift. YES indicates a commanded shift. NO indicates that no shift has been commanded.

Shift Torque: Range 0-510 N·m (0-406 lb ft). This display is the torque value which is used in the commanded pressure calculation during shift. This display indicates the last shift torque.

Shift TP Angle: Range 0-82%. This display is the calculated throttle position angle from throttle position volts at the time a shift is commanded.

Spark: Range -64 to +64 degrees. This is a display of the spark advance calculation which the PCM is programming into the ignition system. The negative numbers indicate degrees after Top Dead Center (TDC) and the positive numbers indicate degrees of advance before Top Dead Center (BTDC). The PCM computes the desired spark advance from inputs such as engine temperature, engine RPM, engine load, vehicle speed, and operating conditions.

Steady St. Mode: Range 0-7. This display indicates which steady state adaptive pressure is in use: 0 = Steady State TAP Reverse; 1 = Steady State TAP 1st Gear; 2 = Steady State TAP 2nd Gear; 3 = Steady State TAP 3rd Gear; 4 = Steady State TAP 4th Gear; 5 = Steady State TAP 2nd Gear/TCC Applied; 6 = Steady State TAP 3rd Gear/TCC Applied; 7 = Steady State TAP 4th Gear/TCC Applied.

Steady St. Slip: Range 0-255. This is the slip accumulator which increments or decrements depending on the clutch slip speed and the torque converter clutch slip speed. This value is used to adapt up or down the steady state adaptive pressure.

Steady St. TAP (Transmission Adapt Pressure): Range 0-127 psi. This display indicates that the steady state pressure modifier is currently in use.

Steady St. TAP D2 (Transmission Adapt Pressure 2nd Gear): Range 0-127 psi. This display indicates a pressure modification which is added to the line pressure in 2nd gear when the PCM detects a worn or slipping component.

Steady St. TAP D2 w/TCC: Range 0-127 psi. This display indicates a pressure modification which is added to the line pressure in 2nd gear with TCC applied when the PCM detects a worn or slipping component.

Steady St. TAP D3 (Transmission Adapt Pressure 3rd Gear): Range 0-127 psi. This display indicates a pressure modification which is added to the line pressure in 3rd gear when the PCM detects a worn or slipping component.

Steady St. TAP D3 w/TCC: Range 0-127 psi. This display indicates a pressure modification which is added to the line pressure in 3rd gear with TCC applied when the PCM detects a worn or slipping component.

Steady St. TAP D4 (Transmission Adapt Pressure 4th Gear): Range 0-127 psi. This display indicates a pressure modification which is added to the line pressure in 4th gear when the PCM detects a worn or slipping component.

Steady St. TAP D4 w/TCC: Range 0-127 psi. This display indicates a pressure modification which is added to the line pressure in 4th gear with TCC applied when the PCM detects a worn or slipping component.

Steady St. TAP L Transmission Adapt Pressure 1st Gear): Range 0-127 psi. This display indicates a pressure modification which is added to the line pressure in 1st gear when the PCM detects a worn or slipping component.

Steady St. TAP R (Transmission Adapt Pressure Reverse): Range 0-127 psi. This display indicates a pressure modification which is added to the line pressure in Reverse when the PCM detects a worn or slipping component.

TCC Brake Switch: Displays Applied or Released. This display indicates the status of the TCC brake switch circuit input to the PCM. APPLIED indicates a zero voltage input (brake switch open). RELEASED indicates a voltage input (brake switch closed).

TCC Commanded: Range 0-255 psi. This display indicates a desired output pressure from the TCC PWM solenoid. This pressure is calculated from the TCC PWM solenoid duty cycle.

TCC Duty Cycle: Range 0-100%. This display indicates the commanded percent of TCC PWM solenoid ON time. 90% represents a fully energized commanded state and 0% represents a de-energized commanded state.

TCC Enable: Displays On or Off. This display indicates the commanded state of the TCC solenoid. ON indicates that the PCM is commanding the TCC solenoid to turn on at a calculated duty cycle. OFF indicates that the PCM is commanding the TCC solenoid to turn off. The commanded states of ON and OFF occur under various vehicle speeds and various PCM inputs.

TCC Slip Speed: Range -4080 to 4079 RPM. This display is the difference between the engine RPM and the RPM of the output shaft of the transmission. A negative value indicates that the engine RPM is less than the RPM of the output shaft (deceleration). A positive value indicates that the engine RPM is greater than the RPM of the output shaft (acceleration).

TCM Cal. ID (Transmission Control Module Calibration Identification): Display shows a four-digit code that uniquely identifies the calibrations stored within the PCM's Flash EEPROM. This displayed number is not the service part number.

TCM Software ID (Transmission Control Module Software Identification): Display shows a four digit code that identifies the level of software for the PCM. This displayed number is not the service part number.

TFT (Transmission Fluid Temperature): Range -40 to 151°C (-40 to 304°F). This display is the temperature conversion of the voltage input signal to the PCM of the transmission fluid temperature. Transmission fluid temperature is high (151°C) when the signal voltage is low (0V). Transmission fluid temperature is low (-40°C) when the signal voltage is high (5.1V).

TFT Sensor (Transmission Fluid Temperature Sensor): Range 0.0-5.0V. This display shows the actual voltage drop across the PCM's internal resistors and the Transmission Fluid Temperature Sensor.

Torque Managed: Displays Yes or No. This display indicates that shift torque management is currently active for an upshift or a downshift. The PCM will regulate engine torque to compensate for these high torque conditions. YES indicates that torque management is active. NO indicates that torques management is inactive.

Torque Spark Ret: Range 0-90 degrees. This display indicates that the PCM is reducing the spark advance in order to reduce engine torque output for transmission protection.

TP Angle (Throttle Position Angle): Range 0-100%. The TP Angle is computed by the PCM from TP voltage. The TP Angle should display 0% at idle and 100% at Wide Open Throttle (WOT).

TP Sensor (Throttle Position Sensor): Range 0.0-5.0V, 0-81.92 degrees. The TP Sensor is used by the PCM to determine the amount of throttle demanded by the driver. By monitoring the TP voltage and degrees, the PCM will modify line pressure and shift times.

TFP Switch:  Displays On or Off, On or Off, On or Off. The displays are the three inputs for Range A/B/C from the transmission fluid Pressure Switch Assembly (PSA). ON represents a low voltage signal (switch closed). OFF represents a high voltage signal (switch open). The sequence of open and closed switches is used by the PCM to determine actual manual valve position. This input is used for line pressure, TCC, and shift solenoid control.

Traction Control: Displays Inactive or Active. This display will show ACTIVE when the PCM receives a signal from the Electronic Brake Traction Control Module (EBTCM) requesting torque reduction during a traction control maneuver.

Trans. ISS (Transmission Input Speed Sensor): Range 0-8191 RPM. This display indicates the rotational speed of the transmission input shaft expressed as revolutions per minute.

Trans. Oil Life: Range 0-100%. This display represents the remaining Transmission Oil Life Index that is calculated and maintained by the PCM.

Trans. OSS (Transmission Output Speed Sensor): Range 0-8191 RPM. This display indicates the rotational speed of the transmission output shaft expressed as revolutions per minute.

Trans. Range: Displays PARK, REVERSE, NEUTRAL, DRIVE 4, DRIVE 3, DRIVE 2, DRIVE 1, OR INVALID. These displays are the decoded status of the three A/B/C range inputs from the Automatic Transmission Fluid Pressure Manual Valve Position Switch (TFP Sw). These displays represent the position of the manual valve.

Upshift: Displays Yes or No. This display indicates when the transmission is in an upshift. YES indicates that an upshift is in progress. NO indicates that an upshift is not in progress.