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 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.

CC: Cruise Control

ED: Engine Data

ET: Electrical/Theft Data

EVAP: EVAP Data

FT: Fuel Trim Data List

HVAC: Heating, Ventilation, Air Condition

IND: Induction Data

IPC: Instrument Panel Control

MF: Misfire Data List

TAC: Throttle Actuated Control Data List

HO2S: HO2S Data

ID: Ignition 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

AC OFF for WOT

HVAC

Yes/No

No

AC Pressure Disable

HVAC

Yes/No

No

A/C Relay Command

IND, ED, MF, HVAC

On/Off

Off

A/C Request

MF, HVAC

Yes/No

No

Air Fuel Ratio

ED, FT, HO2S, IND

Ratio

14.7:1

APP Indicated Angle

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

0-97%

0%

APP Sensor 1

TAC

Volts

1.02 Volts

APP Sensor 1

TAC

0%-99%

0%

APP Sensor 2

TAC

Volts

4.04 Volts

APP Sensor 2

TAC

0%-99%

0%

APP Sensor 1 and 2

TAC

Agree/Disagree

Agree

APP Sensor 1 Circuit Status

TAC

OK/Fault

OK

APP Sensor 2 Circui Status

TAC

OK/Fault

OK

BARO

IND

Volts

Varies with Altitude

BARO

ED, EVAP, FT, HO2S, ID, IND

kPa

65-104 kPa/ Varies w/Altitude

SC Inlet Pressure

IND

kPa

72 kPa

SC Inlet Pressure Sensor

IND

Volts

.45 volts

Boost Duty Cycle

IND

0-99%

99%

Catalytic Converter Protection Active

FT, HO2S

Yes/No

No

CKP Active Counter

ID

1-250

9-250

CMP Active Counter

ID

Counts

Varies

CMP Sensor

ED, ID, MF

RPM

500-700

Cold Start Up

ED, EVAP

Yes/No

Varies

Crank Request Signal

ET

Yes/No

No

Cruise Control Active

TAC, IPC,CC

Yes/No

No

Cruise Disengage 1 History

CC

Various messages

None

Cruise Disengage 2 History

CC

Various messages

None

Cruise Disengage 3 History

CC

Various messages

None

Cruise Disengage 4 History

CC

Various messages

--None

Cruise Disengage 5 History

CC

Various messages

None

Cruise Disengage 6 History

CC

Various messages

None

Cruise Disengage 7 History

CC

Various messages

None

Cruise Disengage 8 History

CC

Various messages

None

Cruise ON/OFF Switch

CC

On/Off

Off

Cruise Resume/Accel. Swithch

CC

On/Off

Off

Cruise Set/Coast Switch

CC

On/Off

Off

Cycles of Misfire Data

MF

0-100 Counts

Varies

Decel Fuel Cutoff

ED, FT, HO2S

Active/Inactive

Inactive

Desired Idle Speed

CC, ED, EVAP, TAC, IND

RPM

PCM Controlled

EC Ignition Relay Feedback Signal

ED, TAC

Volts

14 volts

Engine Oil Life Remaining

IPC

0-100%

Varies

ECT Sensor

ED, EVAP, FT, HO2S, ID, MF, TAC, IND, HVAC, IPC

-40 to -150°C (-40 to +302°F)

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

Engine OFF Time

EVAP

Hours, Minutes, Seconds

Varies

Engine Load

ED, EVAP, FT, HO2S, ID, MF, TAC, IND, HVAC

0-100%

23-24% @ Idle

42% @ 2500 RPM

Engine Oil Pressure Switch

ED, MF, IPC

OK/Low

OK

Engine Run Time

ED, EVAP, HO2S, ID, CC, MF, TAC, IND, HVAC

Hrs, Min, Sec

Varies

Engine Speed

ED, EVAP, FT, HO2S, ID, MF, TAC, IPC, IND, CC, ET, HVAC

0-10,000 RPM

500-700 RPM

EVAP Fault History

EVAP

Various Messages

No Vault

EVAP Purge Solenoid Command

ED, EVAP, FT, HO2S

0-100%

10-30%

EVAP Vent Solenoid Command

ED, EVAP

Not Venting/Venting

Venting

FC Relay 1 Command

HVAC

On/Off

Off

FC Relay 2 Command

HVAC

On/Off

Off

Fuel Tank Level Remaining

ED, EVAP, MF, IPC

0-100%%

Varies

Fuel Tank Pressure Sensor

ED, EVAP

mm/Hg / In H2O

Varies

Fuel Tank Pressure Sensor

EVAP

Volts

Varies

Fuel Trim Cell

ED, EVAP, FT

0-23

16, 17, 21

Fuel Trim Learn

ED, EVAP, FT

Able/Disable

Disabled

Fuel Level Sensor

EVAP, IPC

0-2.5 Volts

Varies

Fuel Pump Relay Command

ED

On/Off

On

Gen F - Terminal Signal

ET

%

35%

Gen L - Terminal Signal

ET

Voltage/No Voltage

No Voltage

HO2S 1

ED, EVAP, FT, HO2S, IND

mV

10-1,000 mV and Varying

HO2S 2

ED, FT, HO2S

mV

10-1,000 mV and Varying

HO2S 1 Heater

HO2S

Amps

Varies

HO2S 2 Heater

HO2S

Amps

Varies

Hot Open Loop

FT, HO2S, HVAC

Active/Inactive

Inactive

IAT Sensor

ED, EVAP, FT, ID, MF, HO2S, IND, TAC, HVAC

-40 to +152°C (-40 to +305°F)

Depends on ambient temperature

Ignition Accessory Signal

ED, ET, IPC, HVAC

On/Off

Off

Ignition 1 Signal

ED, EVAP, FT, HO2S, ID, MF, TAC, HVAC, IND, CC, ET, IPC

0-25 Volts

11.5-14.5 Volts

Intercooler Pump

ID

On/Off

On

Initial Brake Apply Signal

TAC, CC, ED

Applied/Released

Released

Injector PWM

FT, MF

Milliseconds

2-6 ms

Knock Retard

ID, HVAC

Degrees

Long Term FT

ED, EVAP, FT, HO2S

%

Near 0%

Long Term FT Avg

FT

%

%

Loop Status

ED, EVAP, FT, HO2S

Open/Closed

Closed

MAF Sensor

EVAP, FT, HO2S, MF, IND

Hz

Varies

MAF Sensor

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

g/s

Varies

MAP Sensor

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

kPa

20-48 kPa

Medium Resolution Resync Counter

ID

Counts

0

MIL Command

ED, EVAP, ID, IPC

Off/On

Off

MIL Requested By DTC

ED, EVAP, ID

No/Yes

No

Mileage Since DTC Clear

ED

M/Km

Varies

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 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

Non-Driven Wheel Speed

CC, IPC

km/h

0 km/h

PCM Reset

ED, EVAP, ID

Yes/No

No

Power Enrichment

ED, FT, HO2S, MF

Active/Inactive

Inactive

Reduced Engine Power

TAC, IPC

Active/Inactive

Inactive

Reference Voltage 1 Signal

ED, EVAP, ID, TAC, HVAC

Volts

4.98 V

Reference Voltage 2 Signal

ED, EVAP, ID, TAC, HVAC

Volts

4.98 volts

Short Term FT

ED, EVAP, FT, HO2S

%

Near 0%

Short Term FT Avg

FT

%

0%

Spark

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

Degrees

11-20°

Start Up ECT

EVAP, FT, HO2S, HVAC

°C/°F

Varies

Start Up IAT

ET, EVAP, FT, HO2S

°C/°F

Varies

Starter Relay Command

ET

ON/OFF

OFF

Stop Lamp Pedal Switch

TAC, CC, ET

Released/Applied

Released

TFT Sensor

HVAC

C / F

-40°C to +140°C

Total Misfire Count

MF

Count

0

TP Desired Angle

TAC, CC

%

4.2%

TP Sensor 1 Learned Minimum

TAC

Volts

.55 volts

TP Sensor 2 Learned Minimum

TAC

Volts

.55 Volts

Torque Request Signal

TAC, CC

%

Varies

Torque Delivered Signal

TAC

%

Varies

TP Indicated Angle

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

%

4.2%

TP Sensors 1 and 2

TAC

Agree/Disagree

Agree

TP Sensor 1

TAC

0-100%

4%

TP Sensor 2

TAC

0-100%

4%

TP Sensor 1

TAC

0-5.0 volts

4.24 volts

TP Sensor 2

TAC

0-5.0 volts

0.78 volts

Traction Control Status

TAC, CC

Active/Inactive

Inactive

TWC Temperature Calculated

MF

C/F

350°C

Vehicle Security Status

ET

Fuel Enabled/Disabled

Fuel Enabled

Vehicle Speed Sensor

ED, EVAP, HO2S, ID, IPC, CC, MF, TAC, IND, HVAC

km/h

mph

0

Warm-ups w/o Non-Emmisons Faults

ED

Counts

0

Warm-ups w/o Emissions Faults

ED

Counts

0