GM Service Manual Online
For 1990-2009 cars only

The Engine Scan Tool Data List contains all engine related parameters that are available on the scan tool. The list is arranged in alphabetical order. A given parameter may appear in any one of the data lists, and in some cases may appear more than once, or in more than one data list in order to group certain related parameters together.

Use the Engine Scan Tool Data List only after the following is determined:

    • The Diagnostic System Check-Engine Controls is complete.
    • No diagnostic trouble codes (DTCs) are set.
    • The on-board diagnostics are functioning properly.

The scan tool values from a properly running engine may be used for comparison with the engine you are diagnosing. The Engine Scan Tool Data List represents values that would be obtained from a normally running engine.

Important: If a scan tool malfunction is suspected, retest the scan tool on a similar vehicle if possible. A malfunctioning scan tool should not be used. The scan tool problem should be reported to the manufacturer. Use of a faulty scan tool can result in misdiagnosis and unnecessary parts replacement.

Only the parameters listed below are referenced in this service manual for use in diagnosis. Refer to Symptoms - Engine Controls for diagnosis if all values fall within the typical range described in the table.

The column labeled Data List indicates where a parameter is located on the scan tool. Refer to the scan tool operating manual for instructions on how to access the individual data lists. The following is a description of each term listed:

    • Eng 1 = Engine Data 1
    • Eng 2 = Engine Data 2
    • EGR = Exhaust gas recirculation (EGR) Data
    • MSF = Misfire Data
    • ODM = Output Driver Data
    • EVAP = Evaporative emission (EVAP) Data
    • FT = Fuel Trim
    • ALL = Indicates that the parameter appears in all data lists

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Engine Idling/Radiator Hose Hot/Closed Throttle/Trans in Park/Closed Loop/Accessories Off

1-2 Solenoid Circuit Status

ODM

OK / Fault

OK

2-3 Solenoid Circuit Status

ODM

OK / Fault

OK

24X Crank Sensor

Eng 2, MSF

RPM

Varies

A/C High Side Pressure

Eng 2

Volts

Varies

A/C High Side Pressure

Eng 2

kPa

Varies

A/C Off For WOT

Eng 2

Yes / No

No

A/C Pressure Disable

Eng 2

Yes / No

No

A/C Relay Circuit Status

ODM

OK / Fault

OK

A/C Relay Command

Eng 1, Eng 2, EGR, MSF

On / Off

Off

A/C Request Signal

ENG 2

Yes / No

No

Air Fuel Ratio

Eng 2

14.7:1

14.7:1 (Varies)

AIR Pump Relay Circuit Status

ODM

OK / Fault

OK, if equipped with AIR

AIR Pump Relay Command

Eng 1, FT

On / Off

OK, if equipped with AIR

AIR Solenoid Circuit Status

ODM

OK / Fault

OK, if equipped with AIR

AIR Solenoid Command

Eng 1, FT

On / Off

OK, if equipped with AIR

BARO

Eng 1, EGR, EVAP, FT

kPa

Varies depending on altitude

CKP Sensor Status

Eng 2, MSF

Angle / Time A / Time B

Angle

CMP Sensor

Eng 2, MSF

RPM

Varies

CMP Sensor Signal Present

Eng 2, MSF

Yes / No

Yes

Crank Request Signal

Eng 2

Yes / No

No

Cruise Control Active

Eng 1

Yes / No

No

Cruise Inhibit Reason

Eng 1

Engine Not Running, Vehicle Speed, Engine Run Time, Brake, None

Vehicle Speed

Cruise Inhibit Signal Command

Eng 1

On / Off

On

Cruise Inhibit Signal Circuit Status

ODM

OK / Fault

OK

Current Gear

Eng 1, EGR, FT

1 / 2 / 3 / 4 / 9

1

Cycles Of Misfire Data

MSF

Counts

Varies

Cylinder #1 IC Circuit Status

ODM

OK / Fault

OK

Cylinder #2 IC Circuit Status

ODM

OK / Fault

OK

Cylinder #3 IC Circuit Status

ODM

OK/Fault

OK

Cylinder #4 IC Circuit Status

ODM

OK/Fault

OK

Cylinder #5 IC Circuit Status

ODM

OK / Fault

OK

Cylinder #6 IC Circuit Status

ODM

OK / Fault

OK

Cylinder #1 Injector Circuit Status

ODM

OK / Fault

OK

Cylinder #2 Injector Circuit Status

ODM

OK / Fault

OK

Cylinder #3 Injector Circuit Status

ODM

OK / Fault

OK

Cylinder #4 Injector Circuit Status

ODM

OK / Fault

OK

Cylinder #5 Injector Circuit Status

ODM

OK / Fault

OK

Cylinder #6 Injector Circuit Status

ODM

OK / Fault

OK

Decel. Fuel Cutoff

EGR, FT

Active / Inactive

Inactive

Desired EGR Position

EGR

Volts

Varies

Desired EGR Position

Eng 1, EGR, MSF

%

0

Desired Idle Speed

Eng 1, Eng 2, EVAP

RPM

Varies

Driver Module 1 Status

ODM

Enabled / Off - High Volts / Off - High Temp

Enabled

Driver Module 2 Status

ODM

Enabled / Off - High Volts / Off - High Temp

Enabled

Driver Module 3 Status

ODM

Enabled / Off - High Volts / Off - High Temp

Enabled

Driver Module 4 Status

ODM

Enabled / Off - High Volts / Off - High Temp

Enabled

ECT Sensor

Eng 1, Eng 2, EGR, MSF, EVAP, FT

°C, °F

Varies

EGR Flow Test Count

EGR

Counts

0

EGR Learned Minimum Position

EGR

Volts

Varies

EGR Position Sensor

Eng 1, EGR, MSF

%

0

EGR Position Sensor

EGR

Volts

Varies

EGR Position Variance

EGR

%

0

EGR Solenoid Circuit Status

ODM

OK / Fault

OK

EGR Solenoid Command

EGR

%

0%

Engine Load

Eng 1, Eng 2, EGR, MSF, EVAP, FT

%

Varies

Engine Oil Level Switch

Eng 2

OK/Low

OK

Engine Oil Life Remaining

Eng 2

%

Varies

Engine Oil Pressure Sensor

Eng 2

Volts

--

Engine Run Time

Eng 1, Eng 2, EGR, MSF, EVAP, FT

Hr: Min: Sec

Varies

Engine Speed

Eng 1, Eng 2, EGR, MSF, EVAP, FT

RPM

Varies

EVAP Fault History

EVAP

No Fault / Excess Vacuum / Purge Valve Leak / Small Leak / Weak Vacuum

No Fault or No Test Result

EVAP Purge Solenoid Circuit Status

ODM

OK / Fault

OK

EVAP Purge Solenoid Command

Eng 1, EVAP, FT

%

Varies

EVAP Test Abort Reason

EVAP

Not Aborted / Lost Enable / Small Leak / Veh. Not At Rest

Not Aborted or Lost Enable

EVAP Test Result

EVAP

No Result / Passed / Aborted / Fail - DTC P0440 / Fail - DTC P0442 / Fail - DTC P0446 / Fail - DTC P1441

No Result, Passed, or Aborted

EVAP Test State

EVAP

Wait For Purge / Test Running / Test Completed

Varies

EVAP Vent Solenoid Circuit

ODM

OK / Fault

OK

EVAP Vent Solenoid Command

Eng 1, EVAP, FT

Venting / Not Venting

Venting

Extended Travel Brake Pedal Switch

Eng 2

Applied / Released

Released

FC Relay 1 Circuit Status

ODM

OK / Fault

OK

FC Relay 1 Command

Eng 2

On / Off

Varies

FC Relay 2 and 3 Circuit Status

ODM

OK / Fault

OK

FC Relay 2 and 3 Command

Eng 2

On / Off

Varies

Fuel Level

EVAP

%

Varies

Fuel Level Sensor

EVAP

Volts

Varies

Fuel Pump Relay Circuit Status

ODM

OK / Fault

OK

Fuel Pump Relay Command

Eng 1

On/Off

On

Fuel Tank Pressure Sensor

Eng 1, EVAP

mm Hg / in. H2O

Varies

Fuel Tank Pressure Sensor

EVAP

Volts

Varies

Fuel Trim Cell

Eng 1, EVAP, FT

Cell #

0

Fuel Trim Learn

Eng 1, EVAP, FT

Disabled / Enabled

Enabled

GEN F-Terminal Signal

Eng 2

%

Varies

GEN L-Terminal Signal Command

Eng 2

On / Off

On

HO2S 1

Eng 1, EVAP, FT

mV

Varies

HO2S 1 Heater Command

FT

On / Off

Off

HO2S Sensor 1

Eng 1, FT

Ready / Not Ready

Ready

HO2S 2

Eng 1, FT

mV

Varies

IAC Position

Eng 1, EGR, FT

Counts

Varies

IAT Sensor

Eng 1, Eng 2, EGR, EVAP, FT

°C, °F

Varies

Ignition 1 Signal

Eng 1, Eng 2, EGR, EVAP, FT

Volts

12.5-14.5

Ignition Mode

Eng 2

IC / Bypass

IC

Injector PWM

Eng 2, MSF, FT

mS

2.0-4.0

Knock Retard

Eng 1, EGR

Degrees

0

Long Term FT

Eng 1, Eng 2, EVAP, FT

%

Varies

Loop Status

Eng 1, Eng 2, EGR, EVAP, FT

Open / Closed

Closed

MAF Sensor

Eng 1, Eng 2, EGR, MSF, EVAP, FT

g/s

2.0-6.0

MAF Sensor

Eng 2

Hz

Varies

MAP Sensor

Eng 1, Eng 2, EGR, MSF, EVAP, FT

kPa

29-48

MAP Sensor

Eng 1, Eng 2

Volts

1-2

MIL Circuit Status

ODM

OK / Fault

OK

MIL Command

Eng 2

On / Off

Off

Mileage Since DTC Cleared

Eng 2

km / mi

Varies

Misfire Current Cyl. #1

MSF

Counts

0

Misfire Current Cyl. #2

MSF

Counts

0

Misfire Current Cyl. #3

MSF

Counts

0

Misfire Current Cyl. #4

MSF

Counts

0

Misfire Current Cyl. #5

MSF

Counts

0

Misfire Current Cyl. #6

MSF

Counts

0

Misfire History Cyl. #1

MSF

Counts

0

Misfire History Cyl. #2

MSF

Counts

0

Misfire History Cyl. #3

MSF

Counts

0

Misfire History Cyl. #4

MSF

Counts

0

Misfire History Cyl. #5

MSF

Counts

0

Misfire History Cyl. #6

MSF

Counts

0

Number of DTCs

Eng 1, EVAP, FT

--

Varies

O2 Heater Current

Fuel Trim Data

Amps

0.50-0.60

PCM Reset

Eng 1, Eng 2, EGR, ODM, EVAP, FT

Yes / No

No

PCM/VCM in VTD Fail Enable

Eng 1

Yes / No

No

Power Enrichment

Eng 2, MSF

Active / Inactive

Inactive

Reduced Engine Power

Eng 1, EGR

Active / Inactive

Inactive

Short Term FT

Eng 1, Eng 2, EVAP, FT

%

Varies

Spark

Eng 1, Eng 2, MSF, FT

Degrees

20-40

Start Up ECT

Eng 2, EVAP, FT

°C, °F

Varies

Start Up IAT

Eng 2, EVAP, FT

°C, °F

Varies

Starter Enable Relay Circuit Status

ODM

OK / Fault

OK

Starter Relay Command

Eng 2

On / Off

Off

Tachometer Circuit Status

ODM

OK / Fault

OK

TCC Brake Pedal Switch

Eng 1, Eng 2

Applied / Released

Released

TCC Enable Solenoid Circuit Status

ODM

OK / Fault

OK

TCC Enable Solenoid Command

Eng 1, MSF

On / Off

On

TCC PWM Solenoid Command

Eng 2

On / Off

On

TCS Circuit Status

ODM

OK / Fault

OK

TFP Sw.

Eng 2, EGR, FT

Park / Neutral / Drive 1 / Drive 2 / Drive 3 / Drive 4

Varies

TP Sensor

Eng 1, Eng 2

Volts

0.33-1.33

TP Sensor

Eng 1, Eng 2, EGR, MSF, EVAP, FT

%

Varies

Traction Control Status

Eng 2

Active / Allowed / Inhibited / Comm. Link Fail / Trac. PWM Input/Diag. Trac. PWM / Inactive

Allowed

TWC Temperature Calculated

FT

°C/°F

Varies

Vehicle Speed Sensor

Eng 1, Eng 2, EGR, MSF, EVAP, FT

km/h / mph

0

VTD Auto. Learn Timer

Eng 1

Active / Inactive

Inactive

VTD Fuel Disable

Eng 1

Active / Inactive

Inactive

VTD Fuel Disable Until Ign. Off

Eng 1

Yes / No

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