GM Service Manual Online
For 1990-2009 cars only

Scan Tool Output Control

Additional Menu Selection(s)

Description

Crankshaft Position Var. Learn

Output Controls

This function allows the control module to learn the variations in the crankshaft position system. The control module will learn the variations once the following conditions are met:

    • The engine coolant temperature is more than a specified value.
    • All instructions on the scan tool are complete.

Cylinder Power Balance

Output Controls/Fuel System

This function allows the control module to turn off individual fuel injectors. The fuel injector is normally enabled. The control module will disable the fuel injector under the following conditions:

    • All instructions on the scan tool are completed.
    • Engine speed is stable.
    • A fuel injector is selected by the technician on the scan tool.

When the DISABLE is selected the control module will turn OFF the fuel injector for up to 30 seconds, or until commanded ENABLE with the can tool.

Engine Controls Ignition Relay

Output Controls

This function activates the engine control ignition relay. The normal commanded state is NONE. When commanded ON or OFF, the ECM turns the relay ON or OFF. The system remains in the commanded state until cancelled by the scan tool.

Engine Speed Control

Output Controls/TAC System

This function activates the throttle actuator control (TAC) system to change engine speed. The normal commanded state is NONE. Follow the scan tool instructions to enable RPM control. The system will increase or decrease the engine speed between 500 RPM and 2,000 RPM. The increments are 25, 100, and 500 RPM. The system remains in the commanded state until cancelled by the scan tool.

EVAP Purge Solenoid (PWM)

Output Controls/EVAP System

This function activates the EVAP purge solenoid valve. The normal commanded state is 0 percent. The system will INCREASE or DECREASE the amount of purge by changing the duty cycle of the purge valve in 10 percent increments within a range of 0 percent-100 percent. The system remains in the commanded state until cancelled by the tool or the fuel tank pressure (FTP) exceeds -24 mm Hg (-12 in H20).

EVAP Purge/Seal

Output Controls/EVAP System

This function activates two functions. One function increases or decreases the amount of purge by changing the duty cycle of the purge valve and commanding the vent ON, non-venting. The normal commanded state of both valves is NONE. The system will INCREASE or DECREASE the amount of EVAP purge valve opening by 10 percent increments within a range of 0 percent-100 percent. The second function seals the system after using the purge function to obtain a specific amount of fuel tank pressure (FTP). When activated, the purge valve is commanded to 0 percent and the vent valve is commanded ON, non-venting. Both functions remain in the commanded state until cancelled by the tool or the FTP exceeds -24 mm Hg (-12 in H20).

EVAP Vent Solenoid

Output Controls/EVAP System

This function activates the EVAP vent solenoid. The normal commanded state is NONE. When commanded ON, the vent valve switches to non-venting. The system remains in the commanded state unless one of the following conditions occurs:

    • Cancelled by the tool
    •  Purge is greater than 0 percent, and the fuel tank pressure (FTP) exceeds -24  mm Hg (-12 in H20)

Exhaust CMP Actuator

Output Controls/CMP Actuator System

This function controls the exhaust camshaft position (CMP) actuator. The normal commanded state is 0 degrees. The system will INCREASE or DECREASE the exhaust camshaft timing by changing the duty cycle of the actuator in 5-degree increments up to 50 degrees. This also affects Desired Exh.CMP Angle Bank 1 and Bank 2.

Fuel Pump Speed

Output Controls

This function activates the fuel pump speed control module. The normal commanded state is NONE. When commanded ON or OFF, the module turns the fuel pump ON or OFF. If the engine is running and the fuel pump relay is commanded OFF, the engine will stall. The system remains in the commanded state until cancelled by the scan tool.

Fuel Trim Enable

Output Controls/Fuel System

This function enables the fuel trim adjustment.

Fuel Trim Reset

Output Controls/Fuel System

This function activates the reset of fuel trim data in all fuel trim cells.

HO2S Bank 1, Sensor 1

Output Controls/Heated Oxygen Sensors

This function activates the oxygen sensor heater. The normal commanded state is NONE. The system will INCREASE or DECREASE the amount of current in 10 percent increments within a range of 0 percent-100 percent. The system remains in the commanded state until cancelled by the tool.

HO2S Bank 2, Sensor 1

Output Controls/Heated Oxygen Sensors

This function activates the oxygen sensor heater. The normal commanded state is NONE. The system will INCREASE or DECREASE the amount of current in 10 percent increments within a range of 0 percent-100 percent. The system remains in the commanded state until cancelled by the tool.

HO2S Bank 1, Sensor 2

Output Controls/Heated Oxygen Sensors

This function activates the oxygen sensor heater. The normal commanded state is NONE. The system will INCREASE or DECREASE the amount of current in 10 percent increments within a range of 0 percent-100 percent. The system remains in the commanded state until cancelled by the tool.

HO2S Bank 2, Sensor 2

Output Controls/Heated Oxygen Sensors

This function activates the oxygen sensor heater. The normal commanded state is NONE. The system will INCREASE or DECREASE the amount of current in 10 percent increments within a range of 0 percent-100 percent. The system remains in the commanded state until cancelled by the tool.

Intake CMP Actuator

Output Controls/CMP Actuator System

This function controls the intake CMP actuator. The normal commanded state is 0 degrees. The system will INCREASE or DECREASE the intake camshaft timing by changing the duty cycle of the actuator in 5 degree increments up to 40 degrees. This also affects Desired Int. CMP Angle Bank 1 and Bank 2.

Loop Status

Output Controls

This function changes to loop status. The commanded states include Open and Closed. When commanded Open or Closed, the system remains in the commanded state until cancelled by the scan tool.

Malfunction Indicator Lamp (MIL)

Output Controls

This function activates the malfunction indicator lamp (MIL). The commanded states include NONE, ON and OFF. When commanded ON or OFF, the system remains in the commanded state until cancelled by the scan tool.

Misfire Graphic

Output Controls

This function graphs the accumulation of misfires occurring in each cylinder. The system remains in the commanded state until cancelled by the scan tool.

Reset Idle Learn

Output Controls/TAC System

This functions allows the idle speed to be relearned by the control module.

Spark Retard

Output Controls

This function control the amount of spark retard by the control module. The normal commanded state is NONE. The System will increase or Decrease the amount of spark retard from 1-10 degrees maximum retard. The system will remain in the commanded state until cancelled by the scan tool.

Throttle Blade Control

Output controls/TAC System

This function opens the throttle plate in 10 percent increments.

The Scan tool initiates the test when the following conditions are met:

    • The ignition is on with the engine off
    • The vehicle speed is 0 km/h mph

The system remains in the commanded state until cancelled by the scan tool.