GM Service Manual Online
For 1990-2009 cars only

Powertrain Control Module Scan Tool Output Control

Scan Tool Output Control

Additional Menu Selection(s)

Description

Crankshaft Position Variation Learn

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Enables the powertrain control module (PCM) to learn the variations in the crankshaft position (CKP) system. The PCM will learn the variations once the following conditions are met:

    • Engine coolant temperature (ECT) is more than a specific value
    • All the instructions on the scan tool have been completed
    • The accelerator pedal smoothly applied until the fuel cut-off, as specified on the scan tool, is achieved and then immediately released

The PCM learns the variation values on the deceleration from the fuel cut-off.

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 PCM disables the fuel injector when the following conditions are met:

    • All instructions on the scan tool are completed.
    • Stabilized engine speed
    • Fuel injector selected

When DISABLE is selected, the PCM 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 in 10 percent increments from 0 to 100 percent or a maximum of 30 seconds at 100 percent.

Engine Speed Control

TAC System

Activates the throttle activation 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 350-2,000 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 Solenoid

Engine Output Controls/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 Vent Solenoid

Engine Output Controls/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).

EVAP Purge/Seal

Engine Output Controls/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).

Fuel Injector Balance

Fuel System

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

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

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

Fuel Pump

Engine Output Controls

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 PCMs 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.

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.

MIL

Engine Output Controls/Dash Lamps

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

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Misfire Graphic

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

O2S Heater Control

Engine Output Controls

Activates the heated oxygen sensor (HO2S) heater. The commanded states include NONE, ON, and OFF. The normal commanded state is NONE. On a cold engine, with the key ON, engine OFF, the HO2S signal will continue to drop below bias when commanded ON. The system remains in the commanded state until cancelled by the tool.