GM Service Manual Online
For 1990-2009 cars only

Engine Control Module Scan Tool Output Control

Scan Tool Output Control

Additional Menu Selection(s)

Description

CMP Actuator

Output Control/CMP Actuator System

Activates the CMP Actuator. Commands the Desired CMP from 0-40°. The commanded states include NONE, Increase, and Decrease. The normal commanded state is NONE. The system remains in the commanded state until cancelled by the tool.

CMP Actuator Solenoid

Output Control/CMP Actuator System

Activates the CMP Actuator. The commanded states include NONE, ON, and OFF. The normal commanded state is NONE. The system remains in the commanded state until cancelled by the tool.

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

When DISABLE is selected, the control module turns the injector OFF for 30 seconds.

Engine Controls Ignition Relay

Output Control

Activates the Engine Controls Ignition Relay. The commanded states include NONE, ON, and OFF. The normal commanded state is NONE. The system remains in the commanded state until cancelled by the tool.

Engine Speed Control

Engine Speed/Throttle

Activates the throttle actuator control (TAC) system 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 RPM within a range of 400-2,200 RPM. The set step value changes the RPM by increments of 25 RPM, 100 RPM, and 500 RPM. The system remains in the commanded state until cancelled by the scan tool.

EVAP Purge/Seal

Output Control/EVAP System

Simultaneously activates the purge solenoid in 10 percent increments from 0 to 100 percent and the vent solenoid. The device control will be aborted and inhibited if the FTP sensor exceeds 19 mm Hg (10 in H2O).

EVAP Purge Solenoid

Output Control/EVAP System

Activates the purge solenoid in 10 percent increments from 0 to 100 percent. The device control will be aborted and inhibited if the fuel tank pressure (FTP) sensor exceeds 19 mm Hg (10 in H2O).

EVAP Service Bay Test

Service Bay Test

Activates the on-board EVAP diagnostic test.

EVAP Vent Solenoid

Output Control/EVAP System

Activates the vent solenoid. The device control will be aborted and inhibited if the FTP sensor exceeds 19 mm Hg (10 in H2O).

Fuel Composition Reset

Fuel System

Important: Do not use this output control unless the actual alcohol content of the fuel in the tank is 15 percent or less.

This will reset the learned alcohol composition to 0 percent in the engine control module (ECM).

Fuel Pump Relay

Output Control/Fuel Pump

Activates the fuel pump relay for 2 seconds. Also turns fuel pump ON and OFF while engine is running.

Fuel Trim Enable

Fuel System

Disables the ECMs 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

Activates the reset of fuel trim data in all fuel trim cells.

HO2S Heater Sensor 1

Output Control/Heated Oxygen Sensors

Activates the heated oxygen sensor (HO2S) heater. The commanded states include NONE, Increase, and Decrease. The normal commanded state is NONE. The system remains in the commanded state until cancelled by the tool.

HO2S Heater Sensor 2

Output Control/Heated Oxygen Sensors

Activates the heated oxygen sensor (HO2S) heater. The commanded states include NONE, Increase, and Decrease. The normal commanded state is NONE. The system remains in the commanded state until cancelled by the tool.

Idle Spark

Output Control/Spark Control

Disables and enables idle spark advance with the engine running.

IMT Valve

Output Control

Activates the IMT Valve. The commanded states include NONE, ON, and OFF. The normal commanded state is NONE. The system remains in the commanded state until cancelled by the tool.

Loop Status

Output Control

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

Output Control

Activates the malfunction indicator lamp (MIL). The MIL will remain illuminated until cancelled by the scan tool.

Misfire Graphic

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

Spark Retard

Output Control/Spark Control

Controls the amount of spark retard. The scan tool will command an increase or decrease in the amount of spark retard in 1 degree increments, within a range of 1-10 degrees. The normal commanded state is none.

Throttle Position

Engine Speed/Throttle

Operates TAC motor in 10 percent increments to open or close the throttle blade. The test operates during key ON, engine OFF.