GM Service Manual Online
For 1990-2009 cars only

Scan Tool Output Control

Additional Menu Selection(s)

Description

Line PC Solenoid

Line PC Sol. Functional

    • The TCM commands the amperage to the line pressure control solenoid in order to control transmission line pressure. As the amperage increases, the line pressure decreases. As the amperage decreases, the line pressure increases. The amperage range is 0.20-1.10 and may be commanded in one-tenth amp increments.
    • When the engine is running, the following control limits apply:
       - When the transmission range is Park or Neutral, the reference, commanded, amperage may be controlled within calibrated limits. The engine speed must be less than 1,500 RPM. If the engine speed is greater than 1,500 RPM, the message "TR in park/neutral and engine speed over 1,500 RPM" appears on the scan tool display. Both scan tool parameters "Line PC Sol. Ref. Current" and "Line PC Sol. Actual Current" change with the scan tool commands and remain until commanded otherwise.
       - When the transmission range is Park or Neutral, amperage may be controlled within calibrated limits. If the current requested is too high or too low, the message "Requested current for the PC Solenoid is too high" appears on the scan tool display.
       - When the transmission range is not in Park or Neutral, the reference amperage can only be controlled less than the current determined by the TCM. The TCM does not allow a value to be selected that may cause damage to the transmission. If the requested amperage is more than allowed by the TCM, the message "Requested override current out of range" appears on the scan tool display.
       - Transmission range DTCs must not be active. If a transmission range DTC is active, the message "Engine running with transmission DTC present" appears on the scan tool display.

Sheave Ratio Control

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    • The TCM commands the position of the ratio control motor pintle in order to control the speed of the transmission. As the pintle is extended, the speed ratio of the transmission is increased. The speed ratio range is 0.4-1.8 and can be commanded in 0.2 increments.
    • When the engine is running, the following control limits apply:
       - The sheave ratio control may not be commanded to increase the speed ratio, if the engine speed is below a calibrated value. If the solenoid is commanded to increase when the engine speed is too low, the message "Engine Speed Too Low" appears on the scan tool display.
       - The sheave ratio control may not be commanded to increase the speed ratio, if the vehicle speed is below a calibrated value. If the solenoid is commanded to increase when the vehicle speed is too low, the message "Vehicle Speed Too Low" appears on the scan tool display.
       - The sheave ratio control may only command changes in speed ratio when the vehicle is moving within a calibrated vehicle speed range in Drive range. When the transmission range is not Drive and sheave ratio control is attempted, the message "Transmission range must be in drive" appears on the scan tool display.
       - Transmission range DTCs must not be active. If a transmission range DTC is active, the message "Engine running with transmission DTC present" appears on the scan tool display.

TCC Solenoid

TCC Enable Sol. Functional

    • The TCM commands the state of the TCC enable solenoid. The state represents whether the solenoid is directing fluid to the TCC/NI enable signal fluid circuit or not. "Enabled" indicates that the TCC Enable solenoid is ON and is directing fluid to the fluid circuit and thereby allowing the TCC PC solenoid to apply the torque converter clutch. "Disabled" indicates that the TCC Enable solenoid is exhausting fluid from the TCC/NI enable signal fluid circuit. The scan tool TCC enable solenoid parameter should match the commanded state.
    • When the engine is running, the following control limits apply:
       - The TCC enable solenoid may not be commanded enabled if the vehicle speed is below a calibrated value. If the solenoid is commanded ON when the vehicle speed is too low, the message "The Vehicle Speed is Too Low" appears on the scan tool display.
       - Transmission range DTCs must not be active. If a transmission range DTC is active, the message "Engine running with transmission DTC present" appears on the scan tool display.
       - The TCC Enable Sol. Functional control may only command the TCC system ON and OFF when the vehicle is moving within a calibrated vehicle speed range in Drive range. When the transmission range is not Drive and TCC system is commanded ON or OFF, the message "The Vehicle Speed is Too Low" appears on the scan tool display.

TCC Solenoid

TCC PC Sol. Functional

    • The TCM commands the duty cycle of the TCC PC solenoid. The duty cycle is represented by a percentage of ON, energized, time. Approximately 90-100 percent duty cycle represents an ON, energized, commanded state. One percent represents an OFF, non-energized, commanded state. The scan tool TCC Duty Cycle parameter should match the commanded state.
    • When the engine is running, the following control limits apply:
       - The TCC PC solenoid may not be commanded OFF for more than a calibrated amount of time. If the solenoid is commanded OFF for a certain amount of time, the message "TCC OFF time has been exceeded" appears on the scan tool display.
       - The TCC PC solenoid may not be commanded ON if the vehicle speed is below a calibrated value. If the solenoid is commanded ON when the vehicle speed is too low, the message "The Vehicle Speed is Too Low" appears on the scan tool display.
       - The TCC PC Sol. Functional control may only command the TCC system ON and OFF when the vehicle is moving within a calibrated vehicle speed range in Drive range. When the transmission range is not Drive and TCC system is commanded ON or OFF, the message "The Vehicle Speed is Too Low" appears on the scan tool display.
       - Transmission range DTCs must not be active. If a transmission range DTC is active, the message "Engine running with transmission DTC present" appears on the scan tool display.

Trans. Adaptives Reset

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    • The TCM clears, or resets, all TAP cells to zero.
    • There are no limits to using this control. It may be performed with the engine running or when the ignition is ON, and the engine is OFF.