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 Powertrain On-Board Diagnostic (OBD) System Check is completed.
    • No diagnostic trouble codes (DTCs)
    • On-board diagnostics are functioning properly.

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 seen on a normal running engine.

Important: A scan tool that displays faulty data 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. If all values are within the typical range described below, refer to Symptoms - Engine Controls for diagnosis.

The column labeled Data List indicates where a parameter can be located on the scan tool. Refer to the scan tool operating manual for the exact locations of the data lists. The following is a description of each term listed:

All: The Parameter is in all of the data lists indicated below.

Eng 1: Engine Data 1 List

Eng 2: Engine Data 2 List

EGR: EGR Data

EE: Enhanced EVAP Data

FF/FR: Freeze Frame/Failure Records

FT: Fuel Trim Data List

MF: Misfire Data List

TAC: TAC Data List

CC: Cruise Control Data List

Engine Idling/Radiator Hose Hot/Closed Throttle/Park or Neutral/Closed Loop/Accessories Off

Scan Tool Parameter

Vehicle Platform

Data List

Parameter Range/Units

Typical Data Values

4WD Signal

K

Eng 2

Enabled/Disabled

Disabled

4WD Low Signal

K

Eng 2

Enabled/Disabled

Disabled

A/C Clutch Feedback Signal

C ,K

Eng 2

ON/OFF

OFF

A/C Relay Command

C ,K

Eng 1, 2, EGR, MF

On/Off

Off

A/C Compressor Cycling Switch

C ,K

Eng 2

High/Low

Low

A/C Request Signal

C ,K

Eng 2

Yes/No

No

A/C Sec. High Pressure Switch

C ,K

Eng 2

Normal/Low

Normal

Air Fuel Ratio

C ,K

FF, FR

Ratio

14.7:1

AIR Pump Relay Command

(w/NC1)

C ,K

Eng 1, FT

On/Off

Off

APP Average

C ,K

TAC

0-100%

0%

APP Indicated Angle

C ,K

Eng 1, Eng 2, EE, EGR, FT, TAC

0-100%

0%

APP Sensor 1

C ,K

TAC

0-5.0 volts

0.4-0.9 volts

APP Sensor 2

C ,K

TAC

5.0-0 volts

4.5-4.1 volts

APP Sensor 3

C ,K

TAC

5.0-0 volts

4.2-3.7 volts

APP Sensor 1 Angle

C ,K

TAC

0-100%

0%

APP Sensor 2 Angle

C ,K

TAC

0-100%

0%

APP Sensor 3 Angle

C ,K

TAC

0-100%

0%

APP Sensor 1 and 2 Disagree

C ,K

TAC

Yes/No

No

APP Sensor 1 and 3 Disagree

C ,K

TAC

Yes/No

No

APP Sensor 2 and 3 Disagree

C ,K

TAC

Yes/No

No

APP Sensor 1 Out of Range

C ,K

TAC

Yes/No

No

APP Sensor 2 Out of Range

C ,K

TAC

Yes/No

No

APP Sensor 3 Out of Range

C ,K

TAC

Yes/No

No

BARO

C ,K

Eng 1, EE, EGR, FT, FF/FR

kPa

65-104 kPa

Brake Pedal Switch

C ,K

Eng 1, 2, CC

Applied/Released

Released

Clutch Pedal Switch

(Manual Transmission only)

C ,K

Eng 1, EGR

Depressed/Released

Released

CMP Sensor-High to Low

C ,K

Eng 2

Counts

Varies

CMP Sensor-Low to High

C ,K

Eng 2

Counts

Varies

Coolant Level Switch

C ,K

Eng 2

OK/Low

OK

Cruise Control Active

C ,K

Eng 1, TAC

Yes/No

No

Cruise Disengage 1 History

C ,K

CC

Varies

Varies

Cruise Disengage 2 History

C ,K

CC

Varies

Varies

Cruise Disengage 3 History

C ,K

CC

Varies

Varies

Cruise Disengage 4 History

C ,K

CC

Varies

Varies

Cruise Disengage 5 History

C ,K

CC

Varies

Varies

Cruise Disengage 6 History

C ,K

CC

Varies

Varies

Cruise Disengage 7 History

C ,K

CC

Varies

Varies

Cruise Disengage 8 History

C ,K

CC

Varies

Varies

Cruise Inhibit Signal Command

C ,K

Eng 1

ON/OFF

ON

Cruise On/Off Switch

C ,K

CC, TAC

On/Off

Off

Cruise Control Release Brake Pedal Switch

C ,K

CC

On/Off

Off

Cruise Resume/Accel Switch

C ,K

CC, TAC

Resume/Accel

Resume

Cruise Set/Coast Switch

C ,K

CC, TAC

Set/Coast

Coast

Current Gear

C ,K

Eng 1, 2, EGR, FT, FF/FR

0-4

1

Cycles of Misfire Data

C ,K

MF

Counts

Varies

Desired EGR Position

C ,K

Eng 1, EGR, MF, FF/FR

Percent

0%

Desired EGR Position

C ,K

EGR

0-5 volts

Less than 1.3 volts

Desired IAC Airflow

C ,K

Eng 1

g/s

Varies

Desired IAC Airflow

C ,K

Eng 1

Counts

Varies

Desired Idle Speed

C ,K

Eng 1, Eng 2, TAC, EE, FF/FR

RPM

PCM Controlled

DTC Set This Ignition

C ,K

Eng 1, 2, CC, EE, FT

Yes/No

No

ECT Sensor

C ,K

Eng 1, Eng 2, EE, EGR, FT, MF, FF/FR

C/F

88 to 105°C (190 to 221°F)

EGR Learned Minimum POS

C ,K

EGR

0-5.0 volts

Less than 1.3 volts

EGR Position Sensor

C ,K

Eng 1, EGR, FF/FR, MF

0-5.0 volts

Less than 1.3 volts

Engine Load

C ,K

All

Percent

1-4% @ Idle

7-9% @ 2500 RPM

Engine Oil Level Switch

C ,K

Eng 2

OK/Low

Yes

Engine Oil Life Remaining

C ,K

Eng 2

Percent

Varies

Engine Run Time

C ,K

All

Hrs, Min, Sec

Varies

Engine Speed

C ,K

All

RPM

500-700 RPM

EVAP Purge Solenoid Command

C ,K

Eng 1, EE, FT

Percent

10-25%

EVAP Test Abort Reason

C ,K

EE

Varies

Varies

EVAP Test Result

C ,K

EE

Test Result

Varies

EVAP Test State

C ,K

EE

Test State

Varies

EVAP Vent Solenoid Command

C ,K

Eng 1, EE, FT

Not Venting/Venting

Venting

Fail Counter

C ,K

FF, FR

Counts

Varies

Fuel Level Sensor

C ,K

Eng 1, 2, EE

0-5 volts

0.7-2.5 volts

Fuel Level Sensor Rear Tank

C ,K

Eng 1, 2, EE

0-5 volts

0.7-2.5 volts

Fuel Tank Level Remaining

C ,K

EE

Gallon/Liter

Varies

Fuel Tank Level Remaining

C ,K

EE

0-100%

Varies

Fuel Tank Pressure

C,K

Eng 1, EE

-32.7 to +14.0 mm/Hg (-17.5 to +7.5 in/H2O)

Varies

Fuel Tank Pressure

C ,K

EE

0-5.0 volts

Varies

Fuel Tank Rated Capacity

C ,K

EE

98 Liters (25.9 Gallons) or 128 Liters (34 Gallons)

Varies with fuel tank option

Fuel Trim Cell

C ,K

Eng 1, EE, FT

0-23

16, 17

Fuel Trim Learn

C ,K

Eng 1, EE, FT

Enabled/Disabled

Enabled (may Toggle)

Generator F Terminal Signal

C ,K

Eng 2

Percent

Varies

Generator L Terminal Signal Command

C ,K

Eng 2

ON/OFF

ON

HO2S Bank 1 Sensor 1

C ,K

Eng 1, EE, FT

Millivolts

Varies

HO2S Bank 1 Sensor 2

C ,K

Eng 1, FT

Millivolts

Varies

HO2S Bank 2 Sensor 1

C ,K

Eng 1, EE, FT

Millivolts

Varies

HO2S Bank 2 Sensor 2

C ,K

Eng 1, FT

Millivolts

Varies

Fuel Level Sensor

C ,K

Eng 1, 2, EE

0-5 volts

Varies

IAC Position

C ,K

Eng 1, EGR FT

Counts

Varies

IAT Sensor

C ,K

Eng 1, Eng 2, EE, EGR, FT

C/F

Varies

Ignition 1 Signal

C ,K

Eng 1, Eng 2, CC, EE, EGR, FT, TAC

0-25 Volts

11.5-14.5 Volts

Inj. PWM Bank 1 Average

C ,K

Eng 2, FT, FF/FR, MF

Milliseconds

2-6

Inj. PWM Bank 2 Average

C ,K

Eng 2, FT, FF/FR, MF

Milliseconds

2-6

Knock Retard

C ,K

Eng 1, EGR

0.0-16°

Long Term FT Avg. Bn1

C ,K

Eng1, 2, FT

Percentage

Near 0%

Long Term FT Avg. Bn2

C ,K

Eng1, 2, FT

Percentage

Near 0%

Long Term FT Bank 1

C ,K

Eng 1, Eng 2, EE, FT, FF/FR

Percentage

Near 0%

Long Term FT Bank 2

C ,K

Eng 1, Eng 2, EE, FT, FF/FR

Percentage

Near 0%

Loop Status

C ,K

Eng 1, 2, EE, EGR, FT, FF/FR

Open/Closed

Closed

Low Oil Lamp Command

C ,K

Eng 2

On/Off

Off

MAF Sensor

C ,K

All

Grams Per Seconds (g/s)

1-9 g/s @ Idle (depends on altitude)

15-26 g/s @ 2,500 RPM (depends on altitude)

MAF Sensor

C ,K

Eng 2

0-31,999 Hz

2,000-3,000 Hz

MAP Sensor

C ,K

All

kPa

20-48 kPa

MAP Sensor

C ,K

Eng 1, Eng 2

Volts

Varies with altitude

MIL Command

C ,K

Eng 2

Off/On

Off

Mileage Since DTC Cleared

C ,K

Eng 2

km/Miles

Varies

Misfire Current Cyl. 1-8

C ,K

MF

Counts

0

Misfire History Cyl. 1-8

C ,K

MF

Counts

0

Not Run Counter

C ,K

FF, FR

Counts

Varies

Pass Counter

C ,K

FF, FR

Counts

Varies

PCM Reset

C ,K

Eng 1, Eng 2, EGR, EVAP, FT

Yes/No

No

PCM/VCM in VTD Fail Enable

C ,K

Eng 1

Yes/No

No

Reduced Engine Power

C ,K

Eng 1, EGR, TAC

Yes/No

No

Short Term FT Bn1 Average

C ,K

Eng 1, FT

Percentage

Near 0%

Short Term FT Bn2 Average

C ,K

Eng 1, FT

Percentage

Near 0%

Short Term FT Bank 1

C ,K

Eng 1, Eng 2, EE, FT, FF/FR

Percentage

Near 0%

Short Term FT Bank 2

C ,K

Eng 1, Eng 2, EE, FT, FF/FR

Percentage

Near 0%

Spark

C ,K

Eng 1, Eng 2, FT, MF

Degrees

15°-20°

Start Up ECT

C ,K

Eng 2, EE, FT, FF/FR

C°/F°

Varies

Stoplamp Pedal Switch

C ,K

Eng 2, TAC, FF/FR

Applied/Released

Released

TAC/PCM Comm Signal

C ,K

Eng 1, TAC

Yes/No

Yes

TCC Enable Solenoid Command

C ,K

Eng 1, Eng 2, MF, FF/FR

ON/OFF

OFF

TCC PWM Solenoid Command

C ,K

Eng 2

ON/OFF

OFF

TFP Sw.

C ,K

Eng 2, EGR, FT

Transmission Gear Position

Varies

Torque Delivered Signal

C,K

Eng 2

ft/lbs

75

TP Desired Angle

C ,K

Eng 1, Eng 2, EE, EGR, TAC

0-100%

0%

TP Indicated Angle

C ,K

All

0-100%

0%

TP Sensor

C ,K

Eng 1, 2

volts

0.4-0.9 volts

TP Sensor

C ,K

TAEng 1, 2, EGR, FT, MF, EE

volts

.4-.9 volts

TP Sensor

C ,K

TAEng 1, 2, EGR, FT, MF, EE

Percent

Varies

TP Sensor 1

C ,K

TAC

0-5.0 volts

.4-.9 volts

TP Sensor 2

C ,K

TAC

5.0-0 volts

4.8-4.3 volts

TP Sensor 1 Angle

C ,K

TAC

0-100%

0%

TP Sensor 2 Angle

C ,K

TAC

100-0%

100%

TP Sensors Disagree

C ,K

TAC

Yes/No

No

TP Sensor 1 Out of Range

C ,K

TAC

Yes/No

No

TP Sensor 2 Out of Range

C ,K

TAC

Yes/No

No

TR Switch

C ,K

Eng 2, EGR, FT

Transmission Gear Position

Varies

Vehicle Speed Sensor

C,K

All

km/h

mph

0

VTD Auto Learn Timer

C,K

Eng 1

Active/Inactive

Inactive

VTD Fuel Disable

C ,K

Eng 1

Active/Inactive

Inactive

VTD Fuel Disable Until Ign. Off

C ,K

Eng 1

Yes/No

No

Warm-Ups w/o Emission Faults

C ,K

Eng 2

0-255 Counts

Varies

Warm-Ups w/o Non-Emission Faults

C ,K

Eng 2

0-255 Counts

Varies