GM Scan ToolGeneral Motors OBD IIScan Tool Interface

Single Interface Accesses Both Manufacturer-Specific and Generic OBD II Functions

Initial Display

F0: Diagnostics - Contains various submenus used to perform diagnostic functions (look at DTCs, Freeze Frame, etc.)

F1: Service Programming - Reflashing PCM

F2: View Captured Data - Allows you to view any Captured Snapshot Information

Main MenuF0: Diagnostic Trouble Codes (View DTCs)

F1: Data Display (View the data display for Engine/Transmission)

F2: Special Functions (takes you to Output Controls)

F3: Snapshot (allows you to take a snapshot movie of data) parameters around a trigger)

F4: System Information (Readiness Status of Monitors)

F5: ID Information (displays calibration ID and VIN)

Selecting Engine orTransmission Data

Data parameters are groupedby Engine (F0) and Transmission(F1).

Data displays for the engine and transmission are presented in two separategroups

Select the F0 or F1 keys to selectEngine or Transmission

DTC Information

F0: DTC Information lets you look at all stored DTCsF1: Specific DTC lets you view an individual DTC by entering its numberF2: Freeze Frame/Failure Records takes you to a list of all stored Freeze Frame and Failure RecordsF3: Clear DTC Information lets you erase DTCs and FF/FRF4: Diagnostic Test Status takes you to a list that shows the current status of tests that stored Freeze Frame or Fail Records

F0: DTC Information

In addition to allowing you tolook at any History Codes,this menu lets you determine WHEN the test failed.

Use this menu to help you determine if: the DTC set since DTCs were cleared, the test has run and failed it has run and failed this ignition

DTC Display

If a Specific DTC is selected, a display showsits number, a brief description of the DTC,and the test status

Use the test status information to tell youif the test has run, and whether or not the test passed or failed

Freeze Frame/Failure Records

This Application Menu display is an importantone since it contains so many diagnostic options related to system faults (DTCs, FF, FR, etc.)

For example, we can select:F2: Freeze Frame/ Failure Records

Freeze Frame (FF)Failure Records (FR)

The Freeze Frame/Failure Records window shows the Freeze Frame for a DTC that turned on the MIL, and a listof all Fail Records

Cursor down to select thedata to view and hit Enter, or select the function keycorresponding to the FF or FR you want to view (F0, F1, etc.)

Freeze FrameDataThis is the mandated Freeze Frame datarequired by OBD IIregulationsNote that fuel trim is displayed inboth percent and inthe traditional GMFuel Trim Counts

Failure RecordsFailure Record data looks like Freeze Frame. It is a diagnostic enhancement thatstores data for as many as many as five separate faults

Failure Records are the most current diagnostic information and, unlike Freeze Frame, can be updated by the PCM

Clearing DTCs

Choose Clear DTC Information to erase all DTCs from memory

This will erase all DTCs and Freeze Frame, and on 1997 and laterGM vehicles it will reset all Readiness Flags

1995-96 GM vehicles reset only the monitor(s) related to the DTC(s)

Clear DTC Information

You’ll be prompted witha Yes/No choice beforeDTCs are erased

DO NOT erase DTCsunless you have saved Freeze Frame data, or you’ll lose it.

Freeze Frame (FF) is cleared with the DTCinformation

Selecting

Diagnostic Test Status

To view the current statusof a fault-related test,use the Up/Down Arrow Keysto highlight the selection and hit Enter,or push the F4 key

This will take you to theDiagnostic Test Status Display

Diagnostic Test StatusThe Diagnostic TestStatus display lists all FF and FR and their test status

Yes/No in the RAN column tells you if the test ranYes/No in the FAIL column indicates Pass/Fail statusINT suggests the possibility of an intermittent

Use this information before, during, and after repairs to evaluate system status

Data DisplayData Parameters are grouped into four main categories

Engine data parametersare broken into two groups (Engine Data 1 and 2)on vehicles with a large parameter list and some parameters may appear on both lists

Use the groups to concentrate on areas of concern (e.g. EGRconcerns versus misfire)

Data Parameters

Use the white boxes at the bottom of the display to:

Select Items from the data display list for viewing and recordingGo directly to DTCsCapture Data using the snapshot featureThe More choice sends you to other menu options

SpecialFunctions

Want to get tothose bidirectionalcontrols?

The ones we callOutput Tests?

Select Special Functions from this menu

Output Controls

There are several submenuoptions that allow you togo to subsystemsand activate various components

To select Engine Output Controls,hit F0 or hit the Enter keywith F0 highlighted asshown

Engine Output Controls Menu

This display shows a numberof components that you can activate through the scan tool to test their performance

You can use this menu to testthe bulb in the MIL, operatethe fuel pump and cooling fans, etc.

Output Test - Fan Relay

The ON/OFFboxes at the bottomof the screen areused to command the component

In addition, parameters of your choice (Select Items)can be viewedduring the test

EVAP Purge SolenoidOther types of outputcontrols enable youto activate a pulse width modulated component like the EVAP Purge Solenoid and look atthe system response

Here, we’re watching fuel tank pressure and fuel trim as we gradually open the purge using the Decrease andIncrease control buttons

Fuel and IACControls

You can also concentrateon the Fuel or IAC SystemsFuel system controls allow injector balance tests and IAC controlSeparate menu choices let you reset adaptive fuel trim and IAC learned values during or after a repair without having to disconnect the battery

SummaryGM supports all Generic OBD II functions

Individual data parameters can be viewed These parameters are located in groups (Engine 1, Engine 2, etc.)

Various output tests are available, including tests of individual components

In addition to Freeze Frame, the PCM provides GM-specific enhancements: Failure Records, DTC Information, and Diagnostic Test Status display