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 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 conditions are determined:

    •  The Diagnostic System Check-Engine Controls is completed.
    •  There are no diagnostic trouble codes (DTCs).
    • The 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 the values that would be seen on a normal running engine.

Important: Do not use a scan tool that displays faulty data. The scan tool concern should be reported to the manufacturer. Use of a faulty scan tool can result in misdiagnosis and in 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 is located on the scan tool. Review 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 data lists indicated below.

Eng 1: Engine Data 1 List

Eng 2: Engine Data 2 List

Eng 3: Engine Data 3 List

EE: Enhanced EVAP Data

FF: Freeze Frame Data List

FR: Failure Record Data List

FT: Fuel Trim Data List

MF: Misfire Data List

TAC: TAC Data List

Scan Tool Parameter

Data List

Parameter Range/Units

Typical Data Values

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

A/C High Side Pressure

Eng 1, 2, FR

0-3,450 kPa / 0-500 psi

Varies

A/C High Side Pressure Sensor

Eng 1, 2

0-5 Volts

Varies

A/C Off for WOT

Eng 1, TAC

Yes/No

No

A/C Pressure Disable

Eng 1

Yes/No

No

A/C Relay Command

Eng 1, 2, 3

On/Off

Off

A/C Request

Eng 1, 2

Yes/No

No

Air Fuel Ratio Bank 1 or Bank 2

Ft

14.7:1

14.7:1

APP Angle

Eng 1, 2, EVAP, FT, FR, MF, TAC

0-99%

0 percent at idle

APP at Idle

TAC

0-99%

Varies

APP Sensor 1

TAC

0.9-4.5 Volts

1 Volt

APP Sensor 2

TAC

0.45-2.25 Volts

0.5 Volt

Battery Voltage

Eng 1, 2, 3, EVAP, TAC

0-25.5 Volts

12.8-14.2 Volts

Calculated Baro

Eng 1, EVAP, FT

65-104 kPa -16 psi

Varies with altitude

Calc. Converter Temp. (most accurate after warm-up, cruising)

Eng 1, FT

-40 to + 950°C /-40 to + 1742°F

600-900°C/1112-1652°F

Catalyst Overtemp Bn. 1

FT

Yes/No

No

Catalyst Overtemp Bn. 2

FT

Yes/No

No

* Clutch Start Switch (If Equipped)

Eng 1, 2, TAC

On/Off

Off

CMP Active Counter

Eng 2

0-256 Counts

Varies

Cooling Fan After Run

Eng 3, FR

Requested/Not Requested

Not Requested

Commanded Cooling Fan

Eng 2, 3, FR

Off/Low/High and Aux if Equipped

Off

Crank Request

Eng 1, 3

Yes/No

No

* Cruise Clutch Switch (If Equipped)

Eng 1, 3, TAC

Applied/Released

Released

Cruise Engaged

Eng 1, 2, 3, FR, TAC

Yes/No

No

Cruise On/ Off Switch

TAC, FR

On/Off

Off

Cruise Release Brake Pedal Switch

Eng 1, 3, TAC, FR

Applied/Released

Released

Cruise Resume/Accel. Switch

TAC, FR

On/Off

Off

Cruise Set/Coast Switch

TAC, FR

On/Off

Off

Cruise VSS Out of Range

Eng 3, TAC, FR

Yes/No

Yes

Current Gear

Eng 1, 2, 3, FR, FT

P/N/R/1-5

P/N

Decel. Fuel Cutoff

Eng 2, FR, FT

Active/Inactive

Inactive

Delivered Torque PWM Duty Cycle

Eng 2

0-100%

10%

Desired Idle Speed

Eng 1, 2, 3, EVAP, FR, TAC

0-7,000 RPM

650 RPM

Distance Since First Failure

FR

km/mi

Varies

DTC No. 1

Eng 1, EVAP, FT, TAC

PXXXX

Varies

DTC No. 2

Eng 1, EVAP, FT, TAC

PXXXX

Varies

ECM in VTD Fail Enable VTD

Eng 3

Yes/No

No

ECT

Eng 1, 2, 3, EVAP, FF, FR, FT, MF

-39 to +140°C/-38 to +284°F

85-105  °C/185-220°F

Engine At Operating Temperature

FR

Yes/No

Varies

Engine Drag Control Active

TAC

Yes/No

Yes

Engine Idling

FR

Yes/No

Yes

Engine Load

Eng 1, FF

0-99%

2%

Engine Oil Life Remaining

Eng 3

0-100%

Varies

Engine Oil Level Switch

Eng 2, 3

OK/Low

OK

Engine Oil Pressure Switch

Eng 3, FR

OK/Low

OK

Engine Run Time

ALL

0:00:00

Varies

Engine Speed

ALL

RPM

650 RPM

EVAP Canister Purge

Eng 1, EVAP, FR, FT

0-100%

Varies

EVAP Vent Solenoid

Eng 1, EVAP , FR, FT

On/Off

Off

Extended Travel Brake Pedal Switch

Eng 1, 2, 3, TAC

Applied/Released

Released

Fast idle for A/C Performance

Eng 1, TAC

Active/Inactive

Inactive

Fast Idle for Cold Start

TAC

Active/Inactive

Inactive

Fast Idle for Generator Performance

Eng 2, TAC

Active/Inactive

Inactive

Fast Idle for Heater Performance

TAC

Active/Inactive

Inactive

Fast Idle for Hot Start

TAC

Active / Inactive

Inactive

Fuel Level

Eng 1, EVAP , FR, MF

Gal/L

Varies

Fuel Level Sensor Left Tank

Eng 1, EVAP

0-5 Volts

Varies

Fuel Level Sensor Right Tank

Eng 1, EVAP

0-5 Volts

Varies

Fuel Pump Relay Command

Eng 1, FR

On/Off

On

Fuel Tank Pressure

Eng 1, EVAP

in H2O/mm Hg

Varies

Fuel Tank Pressure Sensor

Eng 1, EVAP , FR

0-5 Volts

Varies

GEN L-Terminal Signal Command

Eng 2, FR

On/Off

On

GEN F-Terminal Signal

Eng 2

%

On

HO2S Bank 1 or Bank 2 Sensor 1

Eng 1,2, EVAP, FF, FR, FT

0-4,998 mV

Varies between 30-800 mV

HO2S Bank 1 or Bank 2 Sensor 2

Eng 1, 2, EVAP, FF, FR, FT

0-4,998 mV

Varies 400-700 mV

HO2S Heater Bn 1 or Bn 2 Sen. 1

FT

High/Low

Varies

HO2S Heater Bn 1 or Bn 2 Sen. 2

FT

High/Low

Varies

HO2S Heater Bn 1 or Bn 2 Sen. 1

FT

0-99%

Varies

HO2S Heater Bn 1 or Bn 2 Sen. 2

FT

0-99%

Varies

IAT

Eng 1, 2, 3, EVAP, FF, FR, FT, MF

-39 to +140°C/-38 to +284°F

Varies

Ignition 0

Eng 1, 3, EVAP, FT, TAC

0-25.5 Volts

12.8-14.2 Volts

Ignition 1

Eng 1, 2, 3, EVAP, FR, FT, MF, TAC

0-25.5 Volts

12.8-14.2 Volts

Ignition Dwell

Eng 1

1-4 ms

1.9 ms

Ignition State

Eng 1

On/Cranking/Off

On

Inj. PWM Average Bank 1 or Bank 2

Eng 2, 3, EVAP, FT

0-9 ms

3.0-5.4 ms

Intake Manifold Tuning (IMT) Valve Solenoid

Eng 2, FR

Open/Closed

Closed

Intake Manifold Runner Control (IMRC) Solenoid

Eng 2, FR

Open/Closed

Open

Knock Control

Eng 1, FR

Active/Inactive

Inactive

Knock Sensor 1

Eng 1

0.25-2.67 Volts

4.6-5.4 Volts

Knock Sensor 2

Eng 1

0.25-2.67 Volts

4.6-5.4 Volts

Knock Retard Cyl. 1-6

Eng 1

0-191 Degrees

0 Degrees

LT FT Bn. 1 or Bn. 2 Cruise/Accel.

Eng 1, 2, 3, EVAP, FF, FR, FT

-100 to 100%

0%

LT FT Bn. 1 or Bn. 2 Idle/Decel.

Eng 1, 2, 3, EVAP, FR, FT

-100 to +100%

0%

Loop Status Bank 1 or Bank 2

Eng 1, 2, 3, EVAP, FF, FR, FT

Open/Closed

Closed

MAF

Eng 1, 2, 3, EVAP, FF, FR, FT, MF, TAC

0-655 g/s

3.4-6.3 g/s

MAF Sensor

Eng 1, 3, FR, MF, TAC

0-5 Volts

1.2-1.5 Volts

Main Relay Command

Eng 1

On/Off

On

MIL

Eng 1

On/Off

Off

MIL Flashing

Eng 1

Yes/No

No

Mileage Since DTC Cleared

Eng 1, 3

km/mi

Varies

Mileage Since MIL Request

Eng 1

km/mi

Varies

Misfire Current Cyl. 1-6

MF

0-255 Counts

0

Misfire History Cyl. 1-6

MF

0-255 Counts

0

Number of DTC(s)

Eng 1, EVAP, FT, TAC

#

0

Password Learning Enabled

Eng 3

On/Off

Off

* PNP Switch (If Equipped)

Eng 2, 3, TAC

In Gear /Park/Neutral

Park/Neutral

Power Enrichment

Eng 2, FR, FT

Active/Inactive

Inactive

Power Management (TAC Error)

Eng 3, TAC

Active/Inactive

Inactive

Reduced Power (TAC Error)

Eng 3, TAC

Active/Inactive

Inactive

Requested Torque PWM Duty Cycle

Eng 2, TAC

0-99%

90%

Rough Road Detection

Eng 2, MF

Present/Not Present

Not Present

Short Term FT Bank 1 or Bank 2

Eng 1, 2, 3, EVAP, FF, FR, FT

-100 to +100%

-3% to +3%

Spark Advance

Eng 1, 2, 3, FF, FT

-133 to +78 Degrees

2-5 Degrees

Starter Relay Command

Eng 1, 3

On/Off

Off

Start Up ECT

Eng 2, EVAP, FR, FT

-39 to +140°C/-38 to +284°F

Varies

Start Up IAT

Eng 2, EVAP, FT

-39 to +140°C/-38 to +284°F

Varies

Stoplamp Pedal Switch

Eng 1, 2, 3, FR, TAC

Applied/Released

Released

TAC Forced Engine Idle

Eng 3, TAC

Active/Inactive

Inactive

TAC Learn Counter

TAC

0-255 Counts

Varies

TAC Limit Power

Eng 1, TAC

Yes/No

No

Throttle Actuator DC

Eng 1, TAC

0-99%

Varies

Throttle Plate at Idle

TAC, FR

Yes/No

Yes

Throttle Plate at WOT

TAC, FR

Yes/No

No

TP 1 Learned Min

TAC

0-5 Volts

0-0.5 Volts

TP 2 Learned Min

TAC

5-0 Volts

5-3.7 Volts

TP Angle

Eng 1, 2, 3, EVAP, FF, FR, FT, MF, TAC

0-99%

0 percent

TP Desired Angle

Eng 1, 2, EVAP, FT, TAC

0-99%

Varies

TP Sensor 1

Eng 1, 2, 3, TAC

0-5 Volts

0.5-0.8 Volts

TP Sensor 2

Eng 1, 2, 3, TAC

0-5 Volts

4.1-4.5 Volts

Vehicle Speed

Eng 1, 2, 3, EVAP, FF, FR, FT, MF, TAC

km/mi

Varies

Volumetric Efficiency

Eng 1,2,3, EVAP, FR, FT, TAC

0-100%

13%