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:

    • ENG1 = Engine Data 1
    • ENG2 = 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

ENG2, MSF

RPM

Varies

A/C High Side Pressure

ENG2

Volts

Varies

A/C High Side Pressure

ENG2

kPa

Varies

A/C Off For WOT

ENG2

Yes/No

No

A/C Pressure Disable

ENG2

Yes/No

No

A/C Relay Circuit Status

ODM

OK/Fault

OK

A/C Relay Command

ENG1, ENG2, EGR, MSF

OFF/ON

OFF

A/C Request Signal

ENG2

Yes/No

No

AIR Pump Relay Circuit Status

ODM

OK/Fault

OK, if equipped with AIR

AIR Pump Relay Command

ENG1, FT

On/Off

Off

AIR Solenoid Circuit Status

ODM

OK/Fault

OK, if equipped with AIR

AIR Solenoid Command

ENG1, FT

On/Off

Off

Air Fuel Ratio

ENG2, FT

1

14.7 (Varies)

BARO

ENG1, EGR, EVAP, FT

kPa

Depends on altitude

CKP Sensor Status

ENG2, MSF

Angle/Time A/Time B

Angle

CMP Sensor

ENG2, MSF

RPM

Varies

CMP Sensor Signal Present

ENG2, MSF

Yes/No

Yes

Crank Request Signal

ENG2

Yes/No

No

Cruise Control Active

ENG1

Yes/No

No

Cruise Inhibit Reason

ENG1

--

Engine Not Running, Vehicle Speed, Engine Run Time, Brake

Cruise Inhibit Signal Command

ENG1, ODM

ON/OFF

ON

Current Gear

ENG1, EGR, FT

1/2/3/4

1

Cycles Of Misfire Data

MSF

Counts

Varies

Cyl. #1 IC Circuit Status

ODM

OK/Fault

OK

Cyl. #2 IC Circuit Status

ODM

OK/Fault

OK

Cyl. #3 IC Circuit Status

ODM

OK/Fault

OK

Cyl. #4 IC Circuit Status

ODM

OK/Fault

OK

Cyl. #5 IC Circuit Status

ODM

OK/Fault

OK

Cyl. #6 IC Circuit Status

ODM

OK/Fault

OK

Cyl. #1 Injector Ckt. Status

ODM

OK/Fault

OK

Cyl. #2 Injector Ckt. Status

ODM

OK/Fault

OK

Cyl. #3 Injector Ckt. Status

ODM

OK/Fault

OK

Cyl. #4 Injector Ckt. Status

ODM

OK/Fault

OK

Cyl. #5 Injector Ckt. Status

ODM

OK/Fault

OK

Cyl. #6 Injector Ckt. Status

ODM

OK/Fault

OK

Decel Fuel Cutoff

EGR, FT

Active/Inactive

Inactive

Desired EGR Position

EGR

Volts

Varies

Desired EGR Position

ENG1, EGR, MSF

%

0

Desired Idle Speed

ENG1, ENG2, 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

ENG1, ENG2, EGR, MSF, EVAP, FT

°C, °F

Varies

EGR Flow Test Count

EGR

Counts

0

EGR Learned Minimum Position

EGR

Volts

Varies

EGR Position Sensor

ENG1, 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%

EVAP Fault History

EVAP

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

No Fault or No Test Result

EVAP Purge Solenoid

ENG1, EVAP, FT

%

Varies

EVAP Purge Solenoid Circuit Command

ODM

OK/Fault

OK

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

ENG1, EVAP, FT

--

Venting

Engine Load

ENG1, ENG2, EGR, MSF, EVAP, FT

%

Varies

Engine Oil Level Switch

ENG2

OK/Low

OK

Engine Oil Life Remaining

ENG2

%

Varies

Engine Oil Pressure Sensor

ENG2

Volts

--

Engine Run Time

ENG1, ENG2, EGR, MSF, EVAP, FT

Hr: Min: Sec

Varies

Engine Speed

ENG1, ENG2, EGR, MSF, EVAP, FT

RPM

Varies

Extended Travel Brake Pedal

ENG2

Applied/Released

Released

FC Relay 1 Circuit Status

ODM

OK/Fault

OK

FC Relay 1 Command

ENG2

On/Off

Varies

FC Relay 2 and 3 Circuit

ODM

OK/Fault

OK

FC Relay 2 and 3 Command

ENG2

On/Off

Varies

Fuel Level

EVAP

%

Varies

Fuel Level Sensor

EVAP

Volts

Varies

Fuel Pump Relay Circuit

ODM

OK/Fault

OK

Fuel Pump Relay Command

ENG1

On/Off

On

Fuel Tank Pressure Sensor

ENG1, EVAP

mm Hg/in. H2O

Varies

Fuel Tank Pressure Sensor

EVAP

Volts

Varies

Fuel Trim Cell

ENG1, EVAP, FT

Cell #

0

Fuel Trim Learn

ENG1, EVAP, FT

Disabled/Enabled

Enabled

Gen L-Terminal Signal Command

ENG2

On/Off

On

Generator F-Terminal Signal

ENG2

%

Varies

HO2S Sensor 1

ENG1, FT

Ready/Not Ready

Ready

HO2S 1

ENG1, EVAP, FT

mV

Varies

HO2S 1 Heater Command

FT

On/Off

Off

HO2S 2

ENG1, FT

mV

Varies

IAC Position

ENG1, EGR, FT

Counts

Varies

IAT Sensor

ENG1, ENG2, EGR, EVAP, FT

°C, °F

Varies

Ignition 1 Signal

ENG1, ENG2, EGR, EVAP, FT

Volts

12.5-14.5

Ignition Mode

ENG2

IC/Bypass

IC

Injector PWM

ENG2, MSF, FT

mS

2.0-4.0

Knock Retard

ENG1, EGR

Degrees

0

Long Term FT

ENG1, ENG2, EVAP, FT

%

Varies

Loop Status

ENG1, ENG2, EGR, EVAP, FT

Open/Closed

Closed

MAF Sensor

ENG1, ENG2, EGR, MSF, EVAP, FT

g/s

2.0-6.0

MAF Sensor

ENG2

Hz

Varies

MAP Sensor

ENG1, ENG2, EGR, MSF, EVAP, FT

kPa

29-48

MAP Sensor

ENG1, ENG2

Volts

1-2

MIL Circuit Status

ODM

OK/Fault

OK

MIL Command

ENG2

On/Off

Off

Mileage Since DTC Cleared

ENG2

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

ENG1, EVAP, FT

--

Varies

O2 Heater Current

Fuel Trim Data

Amps

0.50-0.60

PCM Reset

ENG1, ENG2, EGR, ODM, EVAP, FT

Yes/No

--

PCM/VCM in VTD Fail Enable

ENG1

Yes/No

--

Power Enrichment

ENG2, MSF

Active/Inactive

Inactive

Reduced Engine Power

ENG1, EGR

Active/Inactive

Inactive

Short Term FT

ENG1, ENG2, EVAP, FT

%

Varies

Spark

ENG1, ENG2, MSF, FT

Degrees

20-40

Start Up ECT

ENG2, EVAP, FT

°C, °F

Varies

Start Up IAT

ENG2, EVAP, FT

°C, °F

Varies

Starter Enable Relay Circuit Status

ODM

OK/Fault

OK

Starter Relay Command

ENG2

On/Off

Off

Tachometer Circuit Status

ODM

OK/Fault

OK

TCC Brake Pedal Switch

ENG1, ENG2

Applied/Released

Released

TCC Enable Solenoid Command

ENG1, MSF, ODM

On/Off

On

TCC PWM Solenoid Command

ENG2

On/Off

On

Traction Control Status

ENG2

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

Allowed

TCS Circuit Status

ODM

OK/Fault

OK

TFP Switch

ENG2, EGR, FT

Park/Neutral/Drive1/Drive2/Drive3/Drive4

Varies

TP Sensor

ENG1, ENG2

Volts

0.33-1.33

TP Sensor

ENG1, ENG2, EGR, MSF, EVAP, FT

%

Varies

TWC Temperature Calculated

FT

°C/°F

Varies

VTD Auto. Learn Timer

ENG1

Active/Inactive

Inactive

VTD Fuel Disable

ENG1

Active/Inactive

Inactive

VTD Fuel Disable Until

ENG1

Yes/No

--

Vehicle Speed Sensor

ENG1, ENG2, EGR, MSF, EVAP, FT

km/h/mph

0