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 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: Exhaust Gas Recirculation (EGR) Data

EE: Enhanced Evaporative Emission (EVAP) Data

FF/FR: Freeze Frame/Failure Records

FT: Fuel Trim Data List

MF: Misfire Data List

CC: Cruise Control Data List

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

Scan Tool Parameter

Data List

Parameter Range/Units

Typical Data Values

A/C Clutch Feedback Signal

Eng 2

Yes/No

No

A/C Compressor Cycling Switch

Eng 2

Open/Closed

Closed

A/C Relay Command

Eng 1, 2, EGR, MF

On/Off

Off

A/C Request Signal

Eng 2

Yes/No

No

A/C Sec. High Pressure Switch

Eng 2

Open/Closed

Open

Air Fuel Ratio

FF, FR

Ratio

14.7:1

AIR Pump Relay Command

(w/NC1)

Eng 1, FT

On/Off

Off

BARO

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

kPa/volts

65-104 kPa/3.5-4.9 Volts Varies w/Altitude

Brake Pedal Switch

Eng 1, 2, CC

Applied/Released

Released

CMP Sensor-High to Low

Eng 2

Counts

Varies

CMP Sensor-Low to High

Eng 2

Counts

Varies

Coolant Level Switch

Eng 2

Yes/No

No

Cruise Control Active

Eng 1

Yes/No

No

Cruise Disengage 1 History

CC

Varies

Varies

Cruise Disengage 2 History

CC

Varies

Varies

Cruise Disengage 3 History

CC

Varies

Varies

Cruise Disengage 4 History

CC

Varies

Varies

Cruise Disengage 5 History

CC

Varies

Varies

Cruise Disengage 6 History

CC

Varies

Varies

Cruise Disengage 7 History

CC

Varies

Varies

Cruise Disengage 8 History

CC

Varies

Varies

Cruise Inhibit Signal Command

Eng 1

Varies

Varies

Cruise On/Off Switch

CC

On/Off

Off

Cruise Control Release Brake Pedal Switch

CC

On/Off

Off

Cruise Resume/Accel Switch

CC

Resume/Accel

Resume

Cruise Set/Coast Switch

CC

Set/Coast

Coast

Current Gear

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

0-4

1

Cycles of Misfire Data

MF

0-100 Counts

Varies

Desired EGR Position

Eng 1, EGR, MF, FF/FR

0-100%

0%

Desired EGR Position

EGR

0-5 volts

Less than 1.3 volts

Desired IAC Airflow

Eng 1

0-64 g/s

Varies

Desired Idle Speed

Eng 1, Eng 2, EE, FF/FR

RPM

PCM Controlled

DTC Set This Ignition

Eng 1, 2, CC, EE, FT

Yes/No

No

ECT Sensor

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

-39° to +140°C (-38° to +284°F)

88-105°C (190-221°F)

EGR Learned Minimum POS

EGR

0-5.0 volts

Less than 1.3 volts

EGR Position Sensor

Eng 1, EGR, FF/FR, MF

0-5.0 volts

Less than 1.3 volts

Engine Load

All

0-100%

1-4% @ Idle

7-9% @ 2500 RPM

Engine Oil Level Switch

Eng 2

Yes/No

Yes

Engine Oil Life Remaining

Eng 2

0-100%

Varies

Engine Run Time

All

Hrs, Min, Sec

Varies

Engine Speed

All

0-10,000 RPM

500-700 RPM

EVAP Purge Solenoid Command

Eng 1, EE, FT

0-100%

10-25%

EVAP Test Abort Reason

EE

Varies

Varies

EVAP Test Result

EE

Test Result

Varies

EVAP Test State

EE

Test State

Varies

EVAP Vent Solenoid Command

Eng 1, EE, FT

Not Venting/Venting

Venting

Fail Counter

FF, FR

Counts

Varies

Fuel Level Sensor Rear Tank

Eng 1, 2, EE

0-5 volts

0.7-2.5 volts

Fuel Tank Level Remaining

EE

Gallon/Liter

Varies

Fuel Tank Level Remaining

EE

0-100%

Varies

Fuel Tank Pressure

Eng 1, EE

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

Varies

Fuel Tank Pressure

EE

0-5.0 volts

Varies

Fuel Tank Rated Capacity

EE

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

Varies with fuel tank option

Fuel Trim Cell

Eng 1, EE, FT

0-23

16, 17

Fuel Trim Learn

Eng 1, EE, FT

Enabled/Disabled

Enabled (may Toggle)

Generator F Terminal Signal

Eng 2

Percent

Varies

Generator L Terminal Signal Command

Eng 2

Active/Inactive

Active

HO2S Bank 1 Sensor 1

Eng 1, EE, FT

Millivolts

10-1,000 mV and Varying

HO2S Bank 1 Sensor 2

Eng 1, FT

Millivolts

10-1,000 mV and Varying

HO2S Bank 2 Sensor 1

Eng 1, EE, FT

Millivolts

10-1,000 mV and Varying

HO2S Bank 2 Sensor 2

Eng 1, FT

Millivolts

10-1,000 mV and Varying

Fuel Level Sensor

Eng 1, 2, EE

0-5 volts

0.7-2.5 volts

IAC Position

Eng 1, EGR FT

Counts

Varies

IAT Sensor

Eng 1, Eng 2, EE, EGR, FT

-39 to +140°C (-38 to +284°F)

35°C (91°F) Depends on ambient temperature

Ignition 1 Signal

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

0-25 volts

11.5-14.5 Volts

Inj. PWM Bank 1 Average

Eng 2, FT, FF/FR, MF

Milliseconds

2-6

Inj. PWM Bank 2 Average

Eng 2, FT, FF/FR, MF

Milliseconds

2-6

Knock Retard

Eng 1, EGR

0-16°

Long Term FT Avg. Bn1

Eng1, 2, FT

Percentage

Near 0%

Long Term FT Avg. Bn2

Eng1, 2, FT

Percentage

Near 0%

Long Term FT Bank 1

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

Percentage

Near 0%

Long Term FT Bank 2

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

Percentage

Near 0%

Loop Status

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

Open/Closed

Closed

Low Oil Lamp Command

Eng 2

On/Off

Off

MAF Sensor

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

Eng 2

0-31,999 Hz

2,000-3,000 Hz

MAP Sensor

All

kPa

20-48 kPa

MAP Sensor

Eng 1, Eng 2

Volts

1.0-2.0 volts

Varies with altitude

MIL Command

Eng 2

Off/On

Off

Mileage Since DTC Cleared

Eng 2

km/miles

Varies

Misfire Current Cyl. 1-8

MF

0-200 Counts

0

Misfire History Cyl. 1-8

MF

0-65,535 Counts

0

Not Run Counter

FF, FR

Counts

Varies

Pass Counter

FF, FR

Counts

Varies

PCM Reset

Eng 1, Eng 2, EGR, EVAP, FT

Yes/No

No

PCM/VCM in VTD Fail Enable

Eng 1

Yes/No

No

Reduced Engine Power

Eng 1, EGR

Yes/No

No

Short Term FT Bn1 Average

Eng 2, FT

Percentage

Near 0%

Short Term FT Bn2 Average

Eng 2, FT

Percentage

Near 0%

Short Term FT Bank 1

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

Percentage

Near 0%

Short Term FT Bank 2

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

Percentage

Near 0%

Spark

Eng 1, Eng 2, FT, MF

Degrees

15°-20°

Start Up ECT

Eng 2, EE, FT, FF/FR

C°/F°

Varies

Stoplamp Pedal Switch

Eng 2, TAC, FF/FR

Applied/Released

Released

TCC Enable Solenoid Command

Eng 1, Eng 2, MF, FF/FR

Enabled/Disabled

Disabled

TCC PWM Solenoid Command

Eng 2

Percentage

0%

TFP Sw.

Eng 2, EGR, FT

Transmission Gear Position

Varies

TP Desired Angle

Eng 1, Eng 2, EE, EGR

0-100%

0%

TP Indicated Angle

All

0-100%

0%

TP Sensor

Eng 1, 2

Volts

0.4-0.9 volts

TP Sensor

Eng 1, 2, EGR, FT, MF, EE

Volts

0.4-0.9 volts

TR Switch

Eng 2, EGR, FT

Transmission Gear Position

Varies

Vehicle Speed Sensor

All

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

No

Warm-Ups w/o Emission Faults

Eng 2

0-255 Counts

Varies

Warm-Ups w/o Non-Emission Faults

Eng 2

0-255 Counts

Varies