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 that 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

FF/FR: Freeze Frame/Failure Records

FT: Fuel Trim Data List

HO2S: HO2S Data List

MF: Misfire Data List

TAC: Throttle Actuator Control (TAC) Data

Scan Tool Parameter

Data List

Parameter Range/Units

Typical Data Values

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

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 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, EGR, FT, HO2S, TAC, CC

0-100%

0%

APP Sensor 1

TAC

0-100%

0%

APP Sensor 1

TAC

0-5 V

0.4-0.9 V

APP Sensor 2

TAC

0-100%

0%

APP Sensor 2

TAC

5-0 V

4.5-4.1 V

APP Sensor 1 and 2

TAC

Agree/Disagree

Agree

APP Sensor 1 and 3

TAC

Agree/Disagree

Agree

APP Sensor 2 and 3

TAC

Agree/Disagree

Agree

APP Sensor 3

TAC

0-100%

0%

APP Sensor 3

TAC

5-0 V

4.2-3.7 V

Auxiliary Fan Request-if equipped

Eng 2

ON/OFF

OFF

BARO

Eng 1, 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

Yes/No

Varies

Coolant Level Switch

Eng 2

OK/Low

OK

Crank Request Signal

Eng 1

Yes/No

No

Cruise Control Active

Eng 1, TAC, CC

Yes/No

No

Cruise Disengage 1-8 History

CC

Varies

Varies

Cruise On/Off Switch

TAC, CC

ON/OFF

OFF

Cruise Release Brake Pedal Switch

CC

Applied/Released

Released

Cruise Resume/Accel Switch

TAC, CC

ON/OFF

OFF

Cruise Set/Coast Switch

TAC, CC

ON/OFF

OFF

Current Gear-4 speed only

Eng 1, Eng 2, EGR, FT

0-4

1

Cycles of Misfire Data

MF

0-100 Counts

Varies

Decel. Fuel Cutoff

HO2S

Active/Inactive

Inactive

Desired EGR Position

Eng 1, EGR, MF

0-100%

0%

Desired EGR Position

EGR

0-5 V

Less than 1.3 V

Desired Idle Speed

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

RPM

PCM Controlled

DTC Set This Ignition

Eng 1, Eng 2, FT, HO2S, CC

Yes/No

No

ECT Sensor

Eng 1, Eng 2, EGR, FT, HO2S, MF

-39 to +140°C (-38 to +284°F)

88-105°C (190-221°F)

EGR Position Sensor

EGR

0-5 V

Less than 1.3 V

EGR Position Sensor

MF, EGR, Eng 1

0-100%

0%

Engine Load

All

0-100%

1-4% @ Idle

7-10% @ 2,500 RPM

Engine Oil Level Switch-if equipped

Eng 2

OK/Low

OK

Engine Oil Life Remaining

Eng 2

0-100%

Varies

Engine Oil Pressure Sensor

Eng 2

0-5 Volts

1.25 Volts

Engine Run Time

All

Hrs, Min, Sec

Varies

Engine Speed

All

0-10,000 RPM

500-700 RPM

EVAP Purge Solenoid Command

Eng 1, FT

0-100%

0-25%

EVAP Vent Solenoid Command-if equipped

Eng 1, FT

Not Venting/Venting

Venting

Fuel Level Sensor

EE

0-5 V

0.7-2.5 V

Fuel Level Sensor Rear Tank-if equipped

Eng 1

0-5 V

0.7-2.5 V

Fuel Tank Level Remaining

EE

Gal/L

Varies

Fuel Tank Level Remaining

EE

0-100%

Varies

Fuel Tank Pressure (FTP) Sensor-if equipped

Eng 1,

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

Varies

FTP Sensor-if equipped

EE

0-5 V

Varies

Fuel Tank Rated Capacity

EE

98 L (25.9 Gal) or 128 L (34 Gal)

Varies with fuel tank option

Fuel Trim Cell

Eng 1, FT

0-23

16, 20

Fuel Trim Learn

Eng 1, FT

Enabled/Disabled

Enabled-may toggle

Generator F Terminal Signal

Eng 2

%

Varies

Generator L Terminal Signal Command

Eng 2

ON/OFF

ON

HO2S Bank 1 Sensor 1

Eng 1, FT, HO2S

mV

10-1,000 mV and Varying

HO2S Bank 2 Sensor 1

Eng 1, FT, HO2S

mV

10-1,000 mV and Varying

HO2S Heater Bn 1 Sen. 1

HO2S

amps

0.72-0.78 amps

HO2S Heater Bn 2 Sen. 1

HO2S

amps

0.72-0.78 amps

IAT Sensor

Eng 1, Eng 2, EGR, FT, HO2S

-39 to +140°C (-38 to +284°F)

Depends on ambient temperature

Ignition 1 Signal

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

0-25.5 V

11.5-14.5 V

Inj. PWM Bank 1 Average

Eng 2, FT, MF

ms

2-6 ms

Inj. PWM Bank 2 Average

Eng 2, FT, MF

ms

2-6 ms

Knock Retard

Eng 1, EGR

0-16°

Long Term FT Avg. Bn1

FT

%

Near 0%

Long Term FT Avg. Bn2

FT

%

Near 0%

Long Term FT Bank 1

Eng 1, Eng 2, FT, HO2S

%

Near 0%

Long Term FT Bank 2

Eng 1, Eng 2, FT

%

Near 0%

Loop Status

Eng 1, Eng 2, EGR, FT, HO2S

Open/Closed

Closed

Low Oil Lamp Command-if equipped

Eng 2

ON/OFF

OFF

MAF Sensor

Eng 1, Eng 2, EGR, FT, HO2S, MF, TAC

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

Eng 1, Eng 2, EGR, FT, HO2S, MF, TAC

10-105 kPa

20-48 kPa

MAP Sensor

Eng 1, Eng 2

0-5 V

1.0-2.0 V

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, FT

Yes/No

No

PCM/VCM in VTD Fail Enable-if equipped

Eng 1

Yes/No

No

PNP Switch-5 speed only

Eng 2, EGR, FT

Park/Neutral/In gear

Varies

Power Enrichment

Eng 1, Eng 2, HO2S

Yes/No

No

PTO Enable-if equipped

TAC

Yes/No

No

Reduced Engine Power

Eng 1, EGR, TAC, CC

Active/Inactive

Inactive

Short Term FT Avg. Bn1

FT

%

Near 0%

Short Term FT Avg. Bn2

FT

%

Near 0%

Short Term FT Bank 1

Eng 1, Eng 2, FT, HO2S

%

Near 0%

Short Term FT Bank 2

Eng 1, Eng 2, FT, HO2S

%

Near 0%

Spark

Eng 1, Eng 2, FT, HO2S, MF

Degrees

15-20°

Start Up ECT

Eng 2, FT

°C/°F

Varies

Stoplamp Pedal Switch

TAC, CC

Applied/Released

Released

TAC/PCM Communication Signal

Eng 1, TAC, CC

OK/Fault

OK

TCC Brake Pedal Switch

Eng 1, Eng 2

Applied/Released

Released

TCC Enable Solenoid Command-4L80E only

Eng 1, Eng 2, MF, FF/FR

ON/OFF

OFF

TCC PWM Solenoid Command-4L80E only

Eng 2

ON/OFF

OFF

TFP Sw-4L80E only

Eng 2, EGR, FT

Transmission Gear Position

Varies

TP Desired Angle

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

0-100%

3-4.5%

TP Indicated Angle

All

0-100%

3-7%

TP Sensor 1

TAC

0-100%

3%

TP Sensor 1

TAC

0-5 V

0.4-0.9 V

TP Sensor 2

TAC

0-100%

3%

TP Sensor 2

TAC

5-0 V

4.8-4.3 V

TP Sensors 1 and 2

TAC

Agree/Disagree

Agree

TR Switch (4L80E only)

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