GM Service Manual Online
For 1990-2009 cars only
1-2 Sol.: Displays ON or OFF. This parameter is the commanded state 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).

1-2 Sol. Open: 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 PCM.

1-2 Sol. Shorted: Displays Yes or No. this parameter indicates if a short to B+ exists in the 1-2 shift solenoid valve feedback signal to the PCM.

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 Adaptable Shift parameter indicates Yes.

1-2 Shift Time Error/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. This value is only accurate if the Adaptable Shift parameter indicates Yes.

2-3 Sol.: Displays ON or OFF. This parameter is the commanded state 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: 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 PCM.

2-3 Sol. Shorted: Displays Yes or No. this parameter indicates if a short to B+ exists in the 2-3 shift solenoid valve feedback signal to the PCM.

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 Adaptable Shift parameter indicates Yes.

2-3 Shift Time Error/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 1-2 shift time. This value is only accurate if the Adaptable Shift parameter indicates Yes.

2 Gr Start Lamp: Displays On or Off. This parameter indicates that a 2nd gear start has been requested. When On is displayed, the gear start switch turns ON the 2-3 SS Valve and turns OFF the 1-2 SS Valve. The vehicle then starts off in 2nd gear, providing better traction (following gears will shift normally). When Off is displayed, a normal shift program is in effect, and the vehicle starts off in 1st gear. Wide Open Throttle (WOT) overrides the 2nd gear start switch, and the vehicle starts off in 1st gear.

3-2 Downshift Sol./3-2 Down Shift: Displays Yes or No. This parameter indicates if the 3-2 downshift control solenoid is currently commanded On or Off. Yes indicates that the 3-2 shift solenoid is ON. No indicates that the 3-2 shift solenoid is 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 Downshift Sol. Open: Displays Yes or No. This parameter indicates if an open or short to ground exists in the 3-2 shift solenoid feedback signal to the PCM.

3-2 Downshift Sol. Short: Displays Yes or No. This parameter indicates if a short to B+ exists in the 3-2 shift solenoid feedback signal to the PCM.

3-2 Downshift Started: Displays Yes or No. This parameter indicates when the transmission has started a 3-2 downshift. Yes indicates a 3-2 downshift has started. No indicates a 3-2 downshift has not started.

3-2 Downshift In Progress: Displays Yes or No. This parameter indicates whether the transmission is currently in a 3-2 downshift. Yes indicates a 3-2 downshift is in progress. No indicates a 3-2 downshift is not in progress.

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 Adaptable Shift parameter indicates Yes.

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. This parameter is the monitor of the upshift adapt. YES indicates that the adapt capability is functional and displays during shift calculation until the commanded gear changes. NO indicates that the adapt is not functional.

BARO: Displays a range of 10-104 kPa, 0.00-5.00V. The BARO Sensor measures barometric pressure during the ignition ON cycle and during Wide Open Throttle (WOT). This allows the PCM to make fuel delivery, spark timing, and transmission line pressure adjustments for changing altitudes.

Cruise/Cruise Enabled: Displays ON or OFF/Enabled or Disabled. This parameter indicates whether the PCM is allowing cruise operation. The PCM 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/Current TAP: Displays a TP cell range of 0-16. This parameter indicates the current throttle position cell used for line pressure modification (adaptation).

Current TAP (Transmission Adaptive Pressure) Memory/Curr. TAP Memory: Displays a range of -16 to +16 psi. This parameter is the amount of pressure that is added to base line pressure to adjust the holding effort of a clutch or a band, while shifting.

Downshift Desired: Displays Yes or No. This parameter indicates when the PCM is requesting a downshift. Yes indicates a downshift is requested. No indicates a downshift is not requested.

Downshift In Progress: Displays Yes or No. This parameter indicates if the transmission is currently in a downshift. Yes indicates a downshift is in progress. No indicates a downshift is not in progress.

Downshift Requested: Displays Yes or No. This parameter indicates when the PCM is requesting a downshift. Yes indicates a downshift is requested. No indicates a downshift is not requested.

DTC Set This Ignition: Displays Yes or No. This parameter displays Yes if a DTC is active during the current ignition cycle.

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) when the signal voltage is low (0V), and the engine coolant temperature is low (-40°C) when the signal voltage is high (5V).

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.

Gear Ratio: Displays a range of 0.00-3.98-1. This parameter is the actual gear ratio of the current commanded gear.

Hot Mode: Displays ON or OFF. This parameter monitors transmission temperature. OFF indicates the transmission temperature has not exceeded 127°C (261°F). ON indicates the transmission temperature has exceeded 135°C (275°F).

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

Kickdown Enabled: Displays Yes or No. This parameter indicates whether enabling conditions exist for an acceleration mode downshift. No indicates that enabling conditions such as throttle position, vehicle speed, or input speed do not exist for an acceleration mode downshift. Yes indicates that enabling conditions exist for an acceleration mode downshift.

Last Shift Time/Latest Shift: Displays a range of 0.00-6.38 seconds. This parameter is the actual shift time of the last upshift. This value is only accurate if the Adaptable Shift parameter indicates Yes.

Last Shift Time Error/Latest Shift Error: Displays a range of -6.38 to +6.38 seconds. This parameter is the difference between the latest desired shift time and the latest actual shift time. This value is only accurate if the Adaptable Shift parameter indicates Yes.

Long Shift Delay: Displays Yes or No. This parameter indicates whether a long shift delay occurred during the last shift. YES indicates that a long shift delay occurred. NO indicates that a long shift delay did not occur. A shift delay is determined from the time that the PCM commands the shift until the start of the engine RPM drop. When a shift delay is within a range that enables shift adapts, NO is indicated.

Long Shift Time: Displays Yes or No. This parameter indicates whether a long shift time occurred during the last shift. YES indicates that a long shift time occurred. NO indicates that a long shift time did not occur. Shift time is calculated from the beginning of the engine RPM drop to the beginning of the engine RPM increase. When shift time is within a range that enables shift adapts, NO is indicated.

MAF: Displays a range of 0-100%. This parameter indicates the amount of air flow entering the intake manifold. The PCM converts the MAF sensor input signal into grams per second.

MAP (Manifold Absolute Pressure): Displays a range of 10-104 kPa, 0.00-5.00V. The MAP sensor, which is attached to the intake manifold, measures changes in intake manifold pressure. These changes result from engine speed and load changes. The PCM uses this information to adjust fuel delivery and spark plug timing according to incoming air density.

PC (Pressure Control) 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 (Pressure Control) Sol. Ref. 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).

PC (Pressure Control) 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. 0% indicates zero ON time (non-energized) or no current flow. Approximately 60% at idle indicates maximum ON time (energized) or high current flow.

Power Enrichment: Displays Yes or No. This parameter indicates when the power enrichment mode is active (moderate to heavy acceleration). Yes indicates that the power enrichment mode is active. No indicates that the power enrichment mode is not active.

Speed Ratio (5.7L VIN P LT1): Displays a range of 0.00-7.99. This parameter indicates engine speed divided by transmission output speed. This value is used to estimate transmission gear ratio.

Standard TAP (Transmission Adaptive Pressure): Displays Yes or No. The standard TAP is an amount of pressure that is added to the base line pressure. If the shift requires standard TAP to achieve the shift, then the scan tool displays Yes. If the shift requires more or less than the standard TAP to achieve the shift, then the scan tool displays No, indicating that the TAP is out of the standard range.

TCC Brake Switch/Brake Switch: Displays Open or Closed. This parameter indicates the state of the TCC 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. 90% represents an ON (energized) commanded state. 0% represents an OFF (non-energized) commanded state. This commanded state is applied at a vehicle speed greater than approximately 16 km/h (10 mph).

TCC Duty Cycle Open: Displays Yes or No. This parameter indicates whether an open or a short to ground exists in the TCC PWM solenoid feedback signal to the PCM.

TCC Duty Cycle Short: Displays Yes or No. This parameter indicates whether a short to B+ exists in the TCC PWM solenoid feedback signal to the PCM.

TCC Enable: Displays Yes or No/ON or OFF. This parameter is the commanded state of the TCC solenoid. ON indicates a commanded energized state (current is flowing through the solenoid). OFF 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: Displays Yes or No. This parameter indicates whether an open or a short to ground exists in the TCC solenoid feedback signal to the PCM.

TCC Enable Shorted: Displays Yes or No. This parameter indicates whether a short to B+ exists in the TCC solenoid feedback signal to the PCM.

TCC (Torque Converter Clutch) 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).

TCC Stator Temp.: Displays normal or high. This parameter monitors transmission fluid temperature from the TCC (Stator) to the transmission oil cooler. Normal indicates the transmission fluid is within normal operating temperatures. High indicates the transmission fluid temperature has exceeded normal operating temperatures.

Traction Control Delivered Torque: This parameter indicates the percentage of the calculated torque output from the engine to the transmission which is used for traction control system operation.

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) when signal voltage is low (0V), and transmission fluid temperature is low (-40°C) when signal voltage is high (5V).

TFT (Transmission Fluid Temperature) Sensor: Displays a range of 0.00-5.00V. When the transmission fluid is cold, the sensor resistance is high and the PCM will sense high signal voltage. As the transmission fluid temperature warms to normal operating temperature, the sensor resistance becomes less and the voltage decreases to about 1.5-2.0V.

TP (Throttle Position) Sensor: Displays a range of 0.00-5.00V. The TP sensor is used by the PCM 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).

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

TP Range: Displays Normal or Exceeded. This parameter indicates when the throttle position is within a range that enables shift adapts. Normal indicates that the TP is within the range. Exceeded indicates that the TP is not within the range.

TP Delta: Displays Normal or Exceeded. This parameter indicates when the TPS is within a TPS delta range that enables shift adapts. A TPS delta range is how much the TPS is moved during the shift calculation. Normal indicates that the TPS is within the range. Exceeded indicates that the TPS is not within the range.

Traction Control: Displays Active or Inactive. This parameter indicates the status of the TCS/ASR.

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.

Transmission Range (5.7L VIN P LT1): Displays a range of Invalid, Reverse, Drive4/OD, Drive3/D, Drive2, Drive1, or Park/Neutral. These parameters are the decoded status of the three A/B/C range inputs from the Automatic Transmission Fluid Pressure Manual Valve Position Switch Assembly. These parameters represent the position of the transmission manual valve.

TFP Switch: 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.

Upshift Desired: Displays Yes or No. This parameter indicates when the PCM is requesting an upshift. Yes indicates an upshift is requested. No indicates an upshift is not requested.

Upshift In Progress: Displays Yes or No. This parameter indicates if the transmission is currently in an upshift. Yes indicates an upshift is in progress. No indicates an upshift is not in progress.

Upshift Request: Displays Yes or No. This parameter indicates when the PCM is requesting an upshift. Yes indicates an upshift is requested. No indicates an upshift is not requested.

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

VSS Delta: Displays Normal or Exceeded. This parameter indicates when the VSS is within a range that enables shift adapts. Normal indicates that the VSS is within the range. Exceeded indicates that the VSS is not within the range.