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 Engine Controls Diagnostic 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

EE: Enhanced EVAP Data

EGR: Exhaust Gas Recirculation (EGR) Data

FF/FR: Freeze Frame/Failure Records

FT: Fuel Trim Data List

MF: Misfire Data List

TAC: TAC Data

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

Relay ON/Relay OFF

Relay OFF

A/C Compressor Cycling Switch

Eng 2

Low Pressure/Normal

Normal

A/C High Pressure Recirculation Switch

Eng 2

High Pressure/Normal

Normal

AIR Pump Relay Command

(w/NC1)

Eng 1, FT

On/Off

Off

A/C Relay Command

Eng 1, Eng 2, EGR, MF

On/Off

Off

A/C Request Signal

Eng 2

Yes/No

No

APP Average

TAC

Counts

Varies

APP Indicated Angle

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

0-100%

0%

APP Sensor 1

TAC

0-100%

0%

APP Sensor 1

TAC

0-5.0 volts

0.4-0.9 volts

APP Sensor 1 and 2 Disagree

TAC

Agree/Disagree

Agree

APP Sensor 1 and 3 Disagree

TAC

Agree/Disagree

Agree

APP Sensor 2

TAC

0-100%

0%

APP Sensor 2

TAC

5.0-0 volts

4.5-4.1 volts

APP Sensor 2 and 3 Disagree

TAC

Agree/Disagree

Agree

APP Sensor 3

TAC

0-100%

0%

APP Sensor 3

TAC

5.0-0 volts

4.2-3.7 volts

Auxiliary Fan Request (if equipped)

ENG 2

On/Off

Off

BARO

Eng 1, EE, EGR, FT

kPa

65-104 kPa varies w/altitude

CMP Sensor-High to Low

Eng 2

Counts

Varies

CMP Sensor-Low to High

Eng 2

Counts

Varies

Cold Startup

Eng 2, EE

Yes/No

Varies

Coolant Level Switch

Eng 2

OK/Low

OK

Cruise Control Active

Eng 1, TAC

Yes/No

No

Cruise On/Off Switch

TAC

On/Off

Off

Cruise Resume/Accel Switch

TAC

ON/OFF

OFF

Cruise Set/Coast Switch

TAC

ON/OFF

OFF

Current Gear

Eng 1, Eng 2, EGR, FT

0-4

1

Cycles of Misfire Data

MF

0-100 Counts

Varies

Desired EGR Position

Eng 1, EGR, MF

0-100%

0%

Desired EGR Position

EGR

0-5 volts

Less than 1.3 volts

Desired Idle Speed

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

RPM

PCM Controlled

DTC Set This Ignition

Eng 1, Eng 2, EE, FT

Yes/No

No

ECT Sensor

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

-39° to +140°C (-38° to +284°F)

88°C to 105°C (190°F to 221°F)

EGR Closed Value Pintle Position

EGR

0-5 volts

Less than 1.3 volts

EGR Position Sensor

EGR

0-5.0 volts

Less than 1.3 volts

EGR Position Sensor

EGR

0-100%

0%

Engine Load

All

0-100%

1-4% @ Idle

7-9% @ 2500 RPM

Engine Oil Level Switch (if equipped)

Eng 2

OK/Low

OK

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 Result

EE

Passed/Failed

Varies

EVAP Vent Solenoid Command

Eng 1, EE, FT

Not Venting/Venting

Venting

Fuel Level Sensor

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 Sensor (if equipped)

Eng 1, EE

-32.7 to +13.96 mm/Hg (-17.4 to +7.5 in/H2O)

Varies

Fuel Tank Pressure Sensor (if equipped)

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

ON/OFF

ON

HO2S Bank 1 Sensor 1

Eng 1, EE, FT

Millivolts

10-1,000 mV and Varying

HO2S Bank 1 Sensor 2 (if equipped)

Eng 1, EE, 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 (if equipped)

Eng 1, EE, FT

Millivolts

10-1,000 mV and Varying

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, EE, EGR, FT, TAC

0-25.5 volts

11.5-14.5 volts

Inj. PWM Average Bank 1

Eng 2, FT, MF

Milliseconds

2-6 ms

Inj. PWM Average Bank 2

Eng 2, FT, MF

Milliseconds

2-6 ms

Knock Retard

Eng 1, EGR

0-16°

Long Term FT Avg. Bn1

FT

Percentage

Near 0%

Long Term FT Avg. Bn2

FT

Percentage

Near 0%

Long Term FT Bank 1

Eng 1, Eng 2, EE, FT

Percentage

Near 0%

Long Term FT Bank 2

Eng 1, Eng 2, EE, FT

Percentage

Near 0%

Loop Status

Eng 1, Eng 2, EE, EGR, FT

Open/Closed

Closed

Low Oil Lamp Command (if equipped)

Eng 2

On/Off

Off

MAF Sensor

All

0-665 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

10-105 kPa

20-48 kPa

MAP Sensor

Eng 1, Eng 2

0-5 volts

1.0-2.0 volts

Varies with altitude

MIL Command

Eng 2

On/Off

Off

Mileage Since DTC Cleared

Eng 2

Miles/Km

Varies

Misfire Current Cyl. 1-8

MF

0-255 Counts

0

Misfire History Cyl. 1-8

MF

0-65,535 Counts

0

PCM Reset

Eng 1, Eng 2, EGR, EE, FT

Yes/No

No

PCM/VCM in VTD Fail Enable (if equipped)

Eng 1

Yes/No

No

Reduced Engine Power

Eng 1, EGR, TAC

Active/Inactive

Inactive

Short Term FT Avg. Bn1

FT

Percentage

Near 0%

Short Term FT Avg. Bn2

FT

Percentage

Near 0%

Short Term FT Bank 1

Eng 1, Eng 2, EE, FT

Percentage

Near 0%

Short Term FT Bank 2

Eng 1, Eng 2, EE, FT

Percentage

Near 0%

Spark

Eng 1, Eng 2, FT, MF

Degrees

15°-20°

Start Up ECT

Eng 2, EE, FT

C°/F°

Varies

Stoplamp Pedal Switch

Eng 2, TAC

Applied/Released

Released

TAC/PCM Comm Signal

Eng 1, TAC

OK/Fault

OK

TCC Brake Pedal Switch

Eng 1, Eng 2

Applied/Released

Released

TCC Enable Solenoid Command

Eng 1, Eng 2, MF, FF/FR

On/Off

Off

TCC PWM Solenoid Command

Eng 2

On/Off

Off

TFP Switch

Eng 2, EGR, FT

Transmission Gear Position

Varies

TP Desired Angle

Eng 1, Eng 2, EE, EGR, TAC

0-100%

3-4.5%

TP Indicated Angle

All

0-100%

3-4.5%

TP Sensor 1

TAC

0-100%

3%

TP Sensor 1

TAC

0-5.0 volts

0.4-0.9 volts

TP Sensor 2

TAC

0-100%

3%

TP Sensor 2

TAC

5.0-0 volts

4.8-4.3 volts

TP Sensors 1 and 2

TAC

Yes/No

No

TR Switch

Eng 2, EGR, FT

Transmission Gear Position

Park

Vehicle Speed Sensor

All

km/h

mph

0

VTD Auto Learn Timer (if equipped)

Eng 1

Active/Inactive

Inactive

VTD Fuel Disable (if equipped)

Eng 1

Active/Inactive

Inactive

VTD Fuel Disable Until Ign. Off (if equipped)

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