GM Service Manual Online
For 1990-2009 cars only

Scan Tool Output Control

Additional Menu Selection(s)

Description

TCC Control Solenoid

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    • The transmission control module (TCM) commands the torque converter clutch pressure control (TCC PC) solenoid pressure in order to apply and release the TCC.
    • When the ignition is ON, and the engine is OFF, there are no limits to this control. The solenoid remains ON until commanded OFF and vice versa.
    • When the engine is running, the following control limits apply:
       - If the transmission range is Park, and the transmission is in hot mode, the TCC PC solenoid may not be commanded OFF. If the solenoid is requested OFF, the message "TCC OFF command disabled in Hot Mode" appears on the scan tool display.
       - 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.

Shift Solenoid

Shift Solenoid 1

    • The TCM commands Shift Solenoid 1 and Shift Solenoid 2 ON and OFF.
    • When the ignition is ON, and the engine is OFF, there are no limits to this control. The solenoid remains ON until commanded OFF, and vice versa. When the output control is exited, the solenoid state is determined by the TCM.
    • When the engine is running, the following control limits apply:
       - The transmission range must be in Park or Neutral. If the transmission range is not Park or Neutral, the message "Engine running and transmission range is not Park/Neutral" appears on the scan tool display.
       - The solenoid remains ON until commanded OFF, and vice versa. When the output control is exited, the solenoid state is determined by the TCM.
       - 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.

Shift Solenoid 2

Line PC Solenoid

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    • The scan tool is used to request pressure in increments of 200 kPa (30 psi) from 200-2200 kPa (30-320 psi). The TCM will then command the solenoid to achieve a pressure within a range based on the requested pressure. Refer to Solenoid Valve Pressure .
    • When the ignition is ON, and the engine is ON, the pressure request may be controlled within calibrated limits. There are no limits to the output control when the engine is OFF.
    • When the engine is running, the following control limits apply:
       - When the transmission range is Park or Neutral, the pressure request 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.
       - When the transmission range is not Park or Neutral, the requested pressure can only be controlled equal to or greater than the pressure determined by the TCM. The TCM does not allow a pressure to be selected that may cause damage to the transmission. If the requested pressure is less than allowed by the TCM, the message "Requested pressure for the Line PC Solenoid 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.

Clutch PC Solenoids

PC Solenoid 2

    • The TCM commands the pressure control solenoids in order to apply and release the clutches.
    • When the ignition is ON, and the engine is OFF, there are no limits to this control. The solenoid remains ON until commanded OFF, and vice versa. When the output control is exited, the solenoid state is determined by the TCM.
    • When the engine is running, the following control limits apply:
       - The transmission range must be in Park or Neutral. If the transmission range is not Park or Neutral, the message "Engine running and transmission range is not Park/Neutral" appears on the scan tool display.
       - The solenoid remains ON until commanded OFF, and vice versa. When the output control is exited, the solenoid state is determined by the TCM.
       - 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.

PC Solenoid 3

PC Solenoid 4

PC Solenoid 5

Shift Transmission

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    • The TCM commands upshifts and downshifts. The scan tool Commanded Gear parameter should correspond with the shift solenoid combination. Refer to the Shift Solenoid Valve State and Gear Ratio table.
    • When the ignition is ON, and the engine is OFF, there are no limits to this control. The scan tool shift solenoid states change to match the Commanded Gear selected.
    • When the engine is running, the following control limits apply:
       - The TCM does not allow a shift if it causes the engine RPM to exceed a calibrated limit. If a gear is requested and the engine speed is too high, the message "Engine speed too high" appears on the scan tool display.
       - The TCM does not allow a 3-2 or 2-1 downshift if the vehicle speed exceeds a calibrated limit. If either downshift is requested and the vehicle speed is too high, the message "Eng. is on and veh. speed too hi for 3-2 or 2-1 downshift" appears on the scan tool display.
       - The TCM does not allow a 4-3 downshift if the vehicle speed exceeds a calibrated limit. If a 4-3 downshift is requested and the vehicle speed is too high, the message "Vehicle speed too high" appears on the scan tool display.
       - The TCM does not allow an upshift if the vehicle speed exceeds a calibrated limit. If an upshift is requested and the vehicle speed is too high, the message "Vehicle speed too high" appears on the scan tool display.
       - The TCM does not allow an upshift that is greater than the current selected transmission range (PRNDL). For example, 3rd gear is not allowed if the transmission range is D2. If an upshift is requested that is greater than the current selected transmission range, the message "Eng. running and gear request is greater than the current TR" appears on the scan tool display.

High Side Driver 2

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    • The TCM commands the driver for the solenoid voltage supply ON and OFF.
    • When the ignition is ON, and the engine is OFF, there are no limits to this control.
    • High side drivers may not be commanded ON and OFF with the scan tool if the engine is running.

Service Cleaning Procedure

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    • The scan tool is used to start and stop the transmission cleaning procedure algorithm.
    • The following control limits apply:
       - The engine must be running. The message "Engine not Running" will appear on the scan tool if this control is attempted without the engine running.
       - There cannot be active transmission DTCs. The message "Transmission Fault present" will appear on the scan tool if this control is attempted with transmission DTCs active.
       - The transmission range must be Park or Neutral. The message "Transmission not in PARK or NEUTRAL" will appear on the scan tool if this control is attempted with the transmission in any range other than Park or Neutral.
       - The vehicle speed cannot exceed 5 mph. The message "Vehicle Speed too high" will appear on the scan tool if this control is attempted with a vehicle speed greater than 8 km/h (5 mph).
       - The engine speed cannot exceed 2500 RPM. The message "Engine Speed too high" will appear on the scan tool if this control is attempted with an engine speed greater than 2500 RPM.
       - The transmission oil temperature must be at a normal operating temperature. The message "Transmission oil temperature out of range" will appear on the scan tool if this control is attempted without a transmission oil temperature between 70-110°C (158-230°F).

Service Fast Learn Adapts

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    • The scan tool is used to start and stop the transmission Fast Learn Adapt algorithm.
    • The following control limits apply:
       - The engine must be running. The message "Engine not Running" will appear on the scan tool if this control is attempted without the engine running.
       - There cannot be active transmission DTCs. The message "Transmission Fault present" will appear on the scan tool if this control is attempted with transmission DTCs active.