GM Service Manual Online
For 1990-2009 cars only

Scan Tool Output Control

Additional Menu Selection(s)

Description

AIR Pump Relay

AIR System

Activates the secondary air injection (AIR) solenoid relay and AIR pump relay. The normal commanded state of the relay is NONE. With the system commanded ON, the system remains ON for a maximum of 30 seconds.

AIR Solenoid

AIR System

Enables and disables the AIR solenoid.

AIR System

AIR System

Activates the AIR system by turning the AIR pump relay and AIR solenoid ON or OFF

CKP Sensing Decode Mode

--

Enables a specific crank position decode mode. The crank decode modes are ANGLE, TIME A, and TIME B. When entering the output control, the normal commanded state is NONE, the selected state is NONE, and the crank decode mode is ANGLE. To command a specific crank decode mode, change the selected state to the desired mode, and command the mode. The scan tool will require an ignition cycle. After the ignition cycle command the specific crank decode mode. The system will remain in the commanded decode mode until the next ignition cycle.

Cylinder Power Balance

Fuel System

Enables/Disables a cylinder by turning OFF the fuel injector to the cylinder. The fuel injector is normally enabled. The control module disables the fuel injector when the following conditions are met:

    • All instructions on the scan tool have been completed
    • The engine speed has stabilized.
    • A fuel injector selected

When the DISABLE is selected the control module turns the injector OFF for 30 seconds. During this period, the engine operates with a misfire.

EGR Solenoid

Engine Output Controls

Activates the exhaust gas recirculation (EGR) Solenoid that controls EGR valve position. The normal commanded state is NONE. The system will INCREASE or DECREASE the amount of valve opening by 10 percent increments within a range of 0-90 percent. The system remains in the commanded state until cancelled by the tool. If the engine is running, too much EGR will result in a rough idle and/or stalling.

Engine Controls Ignition Relay

--

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

Engine Speed Control

TAC System

Activates the idle air control (IAC) valve to change engine RPM. The normal commanded state is NONE. To enable the RPM control, all instruction on the scan tool must be completed. The system will INCREASE or DECREASE the engine speed. The SET STEP VALUE changes the engine speed by increments of 25 RPM, 100 RPM, and 500 RPM. The system remains in the commanded state until cancelled by the tool.

EVAP Purge Solenoid

EVAP System

Activates the EVAP Purge Valve. The normal commanded state is NONE. The system will INCREASE or DECREASE the amount of EVAP purge valve opening by 10 percent increments within a range of 0-100 percent. The system remains in the commanded state until cancelled by the tool or the fuel tank pressure exceeds 24 mm Hg (12 in H20).

EVAP Test

Service Bay Tests

Activates the Service Bay Test to verify the integrity of the EVAP System. The scan tool initiates the test when the following conditions are met:

    • All instructions on the scan tool have been completed.
    • The engine coolant temperature is less than a specified value.
    • No DTCs are set.

EVAP Purge/Seal

Engine Output Controls/EVAP System

This control enables 2 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 0-100 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

Engine Output Controls/EVAP System

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 exceeds 24 mm Hg (12 in H20)

Fuel Injector Balance

Fuel System

Enables fuel injector in order to verify proper fuel injector flow. The PCM will pulse the selected injector when the following conditions are met:

    • All instructions on the scan tool have been completed.
    • Fuel injector selected
    • Key ON, engine OFF

The selected fuel injector can only be flowed/pulsed once per ignition cycle.

Fuel Pump Relay

Fuel Pump

Controls the fuel pump relay. The normal commanded state is NONE. When commanded ON/OFF, the PCM turns the fuel pump ON/OFF. If the engine is running, and the fuel pump is commanded OFF, the engine will stall. The system remains in the commanded state until cancelled by the scan tool.

Fuel Trim Enable

Fuel System

Disables the control modules ability to learn new fuel trim parameters. The commanded states are NONE, ENABLED, DISABLED. The normal commanded state is NONE. The system remains in the commanded state until cancelled by the scan tool.

Fuel Trim Reset

Fuel System

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

HO2S Heater Bank 1 Sensor 1 Command

Heated Oxygen Sensor

Activates the HO2S bank 1 sensor 1 heater. The commanded states include NONE, ON, and OFF. The normal commanded state is NONE. Commanding the HO2S bank 1 sensor 1 heater ON turns on the heater driver. The system remains in the commanded state until cancelled by the tool.

HO2S Heater Bank 1 Sensor 2 Command

Heated Oxygen Sensor

Activates the HO2S bank 2 sensor 1 heater. The commanded states include NONE, ON, and OFF. The normal commanded state is NONE. Commanding the HO2S bank 2 sensor 1 heater ON turns on the heater driver. The system remains in the commanded state until cancelled by the tool.

HO2S Heater Bank 2 Sensor 1 Command

Heated Oxygen Sensor

Activates the HO2S bank 1 sensor 2 heater. The commanded states include NONE, ON, and OFF. The normal commanded state is NONE. Commanding the HO2S bank 1 sensor 2 heater ON turns on the heater driver. The system remains in the commanded state until cancelled by the tool.

Idle Spark

Spark

Disables and enables idle spark advance with the engine running.

Loop Status

Engine Output Controls

Controls the system loop status. The commanded states include NONE, OPEN, or CLOSED. The normal commanded state is NONE. When commanded OPEN or CLOSED, the system remains in the commanded state until cancelled by the scan tool.

Malfunction Indicator Lamp

Dash Lamps

Controls 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

--

Graphs the accumulated misfires occurring in each cylinder. The scan tool allows for a reset of the misfire graph.

Spark Retard

Engine Output Controls

Controls the amount of spark retard. The normal commanded state is NONE. The system will INCREASE or DECREASE the amount of spark retard by 1 degree increments within a range of 0-10 degrees maximum retard. The system remains in the commanded state until cancelled by the tool.

Throttle Position

TAC System

This function opens the throttle plate in 25 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.