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 DTCs
    • On-board diagnostics (OBDs) 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:

AIR: Secondary Air Injection Reaction Data

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

CC: Cruise Control Data

CMP: Camshaft Position Data

COOL: Cooling/HVAC Data

ED: Engine Data

ET: Electrical/Theft Data

EVAP: EVAP Data

FT: Fuel Trim Data

HO2S: Heated Oxygen Sensor Data

ID: Ignition Data

IM: IM Data

IPC: IPC Data

MF: Misfire Data

TAC: Throttle Actuated Control Data

Scan Tool Parameter

Data List

Parameter Range/Units

Typical Data Values

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

5-Volt Reference 1

AIR, EVAP, COOL, ID, IND, TAC

Volts

5 Volts

5-Volt Reference 2

AIR, EVAP, COOL, ID, IND, TAC

Volts

5 Volts

5-Volt Reference 1 Circuit Status

AIR, EVAP, COOL, ID, IND, TAC

Fault/OK

OK

5-Volt Reference 2 Circuit Status

AIR, EVAP, COOL, ID, IND, TAC

Fault/OK

OK

A/C High Side Pressure

COOL

Volts

1.33 Volts

A/C High Side Pressure

COOL

psi

109 psi

A/C Off for WOT

COOL

Yes/No

No

A/C Pressure Disable

COOL

Yes/No

No

A/C Relay Circuit Status

COOL

Closed/Incomplete

Incomplete

A/C Relay Command

Air, COOL, ED, IND, MF, TAC

On/Off

Off

A/C Request Signal

COOL

Yes/No

No

Air Fuel Ratio

AIR, ED, FT, HO2S, IND

Ratio

14.7:1

Air Indicated Pressure

AIR

kPa/psi

0 kPa/0 psi

Air Pressure Sensor

AIR

kPa/psi

96 kPa/13 psi

Air Pressure Sensor

AIR

Volts

2.59 Volts

Air Pressure Sensor Variance

AIR

kPa/psi

0 kPa/0 psi

Air Pump Relay Circuit

AIR

OK/Indeterminate

OK

Air Pump Relay Command

AIR

On/Off

Off

Air Solenoid Circuit Status

AIR

OK/Indeterminate

Indeterminate

Air Solenoid Command

AIR

On/Off

Off

Ambient Air Temperature

ED

Degrees

23°C (73°F)

APP Indicated Angle

AIR, CC, CMP, ED, ET, EVAP, FT, HO2S, ID, IND, MF, TAC

0-96%

0%

APP Sensor 1

TAC

%/Volts

0%/0.96 Volts

APP Sensor 2

TAC

%/Volts

0%/4.51 Volts

APP Sensor 1 and 2

TAC

Agree/Disagree

Agree

APP Sensors

TAC

%

0%

APP Sensor 1 Indicated Position

TAC

%

0%

APP Sensor 2 Indicated Position

TAC

%

0%

BARO

ED, EVAP, ID, EE, FT, IM, IND, AIR, HO2S

kPa

65-104 kPa/Varies w/Altitude

Calc. TWC Temp.

FT, MF

Degrees

531°C (982°F)

Catalytic Converter Projection Active

FT, HO2S

Yes/No

No

CKP Active Counter

ID

Counts

11-241

CKP Sensor

ID

RPM

599-619 RPM

CMP Active Counter

CMP, ID

Counts

Varies

CMP Command

CMP

%

0%

CMP Sensor

CMP, ED, ID, MF

RPM

Varies

Cold Start-Up

AIR, ED, EVAP, IM

Yes/No

Yes

Crank Request Signal

ET

Yes/No

No

Cruise Control Active

ED

Active/Inactive

Inactive

Cruise Control Active

CC, TAC, IPC

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 On/Off Switch

CC

On/Off

Off

Cruise Resume/Accel Switch

CC

Active/Inactive

Inactive

Cruise Set/Coast Switch

CC

Active/Inactive

Inactive

Cycles of Misfire Data

MF

Counts

Varies

Decel Fuel Cutoff

ED, FT, HO2S

Active/Inactive

Inactive

Desired Exh. CMP

CMP

Degrees

0 Degrees

Desired Idle Speed

CMP, EVAP, TAC

RPM

600 RPM

EC Ignition Relay Feedback Signal

ED, ET, EVAP, TAC

Volts

B+

ECT Sensor

ALL

-40 to +151°C (-40 to +303°F)

88-105°C (190-221°F) Depends on ambient temperature

Engine Load

AIR, CMP, HO2S, IND, ED, FT, MF, TAC, ID, EVAP

0-100%

23-24% @ Idle

7-42% @ 2,500 RPM

Engine OFF Time

EVAP

Time

Varies

Engine Oil Pressure Switch

CMP, ET, ED, IPC

OK/Low

OK

Engine Oil Temperature Calculated

COOL, CMP, IPC

Degrees

82°C (170°F)

Engine Run Time

All

Hrs, Min, Sec

Varies

Engine Speed

All

RPM

500-700 RPM

EVAP Fault History

EVAP

Fault/No Fault

No Fault

EVAP Purge Solenoid Circuit Status

EVAP

OK/Indeterminate

Indeterminate

EVAP Purge Solenoid Command

ED, EVAP, FT, HO2S

%

18%

EVAP Vent Solenoid Circuit Status

EVAP

OK/Incomplete

Incomplete

EVAP Vent Solenoid Command

ED, EVAP

Not Venting/Venting

Not Venting

Exh. CMP Angle

CMP

Degrees

0 Degrees

Extended Travel Brake Pedal Switch

TAC

Applied/Released

Applied

Fuel Pump Relay Circuit

ED

Fault/OK

OK

Fuel Tank Pressure Sensor

ED

mm/Hg/In H2O

Varies

Fuel Tank Pressure Sensor

EVAP

mm/Hg/In H2O/Volts

1.5 Volts

Fuel Tank Pressure Sensor

EVAP

mm/Hg/in H20

11.2 mm/Hg /5.9 in H2O

Fuel Trim Cell

FT

0-23

16, 17, 21

Fuel Level Sensor

IPC, EVAP

Volts

2.2 Volts

Fuel Pump Relay Command

ED

On/Off

On

Fuel Tank Level Remaining

FT, MF, ED, EVAP, IM, IPC

%

Varies

Fuel Trim Learn

ED, FT

Enable/Disable

Disable

Generator F-Terminal Signal

ET

Percent

Varies

Generator L-Terminal Signal Command

ET

ON/OFF

ON

HO2S 1

ED, EVAP, FT, HO2S, AIR, IND

mV

0-725 mV and Varying

HO2S 1 Heater

HO2S

Amps

1.12-1.14 Amps

HO2S 1 Heater Circuit Status

HO2S

Fault/OK

OK

HO2S 1 Heater Command

HO2S

%

0%

HO2S 1 Heater Current

FT

Amps

Varies

HO2S 2

ED, FT, HO2S

mV

10-1,000 mV and Varying

HO2S 2 Heater

HO2S

Amps

Varies

HO2S 2 Heater Circuit Status

HO2S

Fault/OK

OK

HO2S 2 Heater Command

HO2S

%

0%

Hot Open Loop

FT, HO2S, COOL

Active/Inactive

Inactive

Ignition Accessory Signal

ET, ED, IPC

On/Off

Off

IAT Sensor

ED, EVAP, ID, FT, MF, CMP, AIR, HO2S, COOL

-40 to +151°C (-40 to +303°F)

Depends on ambient temperature

Ignition 1 Signal

ALL

0-25 Volts

11.5-14.5 Volts

Injector PWM

ED, FT, MF

Milliseconds

2-6 ms

Knock Retard

COOL, ID

0-16°

Long Term FT

AIR, HO2S, ED, EVAP, FT

%

3-6%

Long Term FT Avg

FT

Lambda

1.06

Long Term FT Test Avg. w/o Purge

FT

Lambda

1.02

Loop Status

ED, EVAP, FT, HO2S

Open/Closed

Closed

Low EOP Indicator Command

IPC

On/Off

Off

MAF Sensor

AIR, CMP, ED, EVAP, FT, HO2S, ID, IND, MF, TAC

g/s

Varies

MAF Sensor

EVAP, FT, IND

Hz

Varies

MAP Sensor

AIR, CMP, ED, EVAP, FT, ID, IND, TAC, MF

kPa

27-78 kPa

MAP Sensor

IND, CMP

Volts

0.53 Volts

Distance Since DTC Cleared

ED

Miles/Km

Varies

MIL Command

ED, IM, IPC

Off/On

Off

MIL Requested By DTC

AIR, CMP, ED, ET, EVAP, HO2S, ID, IND, MF, TAC

Yes/No

No

Misfire Current Cyl #1

MF

Varies

0

Misfire Current Cyl #2

MF

Varies

0

Misfire Current Cyl #3

MF

Varies

0

Misfire Current Cyl #4

MF

Varies

0

Misfire Current Cyl #5

MF

Varies

0

Misfire History Cyl #1

MF

Varies

0

Misfire History Cyl #2

MF

Varies

0

Misfire History Cyl #3

MF

Varies

0

Misfire History Cyl #4

MF

Varies

0

Misfire History Cyl #5

MF

Varies

0

PCM/VCM in VDT Fail Enable

ET

Yes/No

Yes

Power Enrichment

ED, FT, HO2S, MF

Active/Inactive

Inactive

Reduced Engine Power

ED, TAC, CC

Active/Inactive

Inactive

Short Term FT

AIR, ED, EVAP, FT

%

0-3%

Short Term FT Avg

FT

Lambda

1.01-1.02

Spark

CC, COOL, ED, FT, HO2S, ID, IND, MF

Degrees

11-20°

Start Up ECT

AIR, COOL, ED, EVAP, FT, HO2S, IM

°C/°F

Varies

Starter Relay Circuit Status

ET, IM

OK/Indeterminate

Indeterminate

Starter Relay Command

ED

On/Off

Off

Start-up IAT

AIR, COOL, EVAP, FT, HO2S, IM

Degrees

Varies

TAC Forced Engine Shutdown

TAC

Yes/No

No

TAC Motor

TAC

Enabled/Disabled

Enabled

TCC Enable Solenoid Command

ED

ON/OFF

OFF

Total Misfire

MF

Counts

0

TP Desired Angle

TAC, CC

%

4.2%

TP Indicated Angle

ED, EVAP, FT, ID, HO2S, TAC, MF, CC, CMP

%

3%

TP Sensor 1 Learned Minimum

TAC

Volts

0.49 Volt

TP Sensor 2 Learned Minimum

TAC

Volts

0.47 Volt

TP Sensors 1 and 2

TAC

Agree/Disagree

Agree

TP Sensor 1 Indicated Angle

TAC

0-100%

3%

TP Sensor 2

TAC

0-100%

3%

TP Sensor 1

TAC

0-5 Volts

4.37 Volts

TP Sensor 2

TAC

0-5 Volts

0.59 Volt

Traction Control Status

CC, TAC

Active/Inactive

Inactive

Vehicle Speed Sensor

All

km/h

mph

0

VTD Fuel Disable

ED, ET

Active/Inactive

Inactive

VTD Auto. Learn Timer

ED, ET

Active/Inactive

Inactive

VTD Fuel Disable Until Ignition Off

ED, ET

Yes/No

No

Warm-up W/O Non-Emission Faults

ED

Numeric

Varies

Warm-up W/O Emission Faults

ED

Numeric

Varies

Wide Open Throttle

TAC

Yes/No

No