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 - Vehicle 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.

CMP: CMP Actuator Data

ED: Engine Data

EVAP: EVAP Data

FT: Fuel Trim Data List

IND: Induction Data

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

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

5-Volt Reference 1

EVAP, ID, IND, TAC

Volts

4.5 Volts

5-Volt Reference 1 Circuit Status

ID, IND, TAC

OK/Incomplete/Short B+/ Short Ground/ Short Open

OK

5-Volt Reference 2

EVAP, ID, IND, TAC

Volts

4.5 Volts

5-Volt Reference 2 Circuit Status

ID, IND, TAC

OK/Incomplete/Short B+/ Short Ground/ Short Open

OK

A/C Relay Command

ED, MF, IND, TAC

On/Off

Off

Air Flow Calculated

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

g/s

3-5 g/s

Ambient Air Temp

ED, EVAP

Degrees

Varies

APP Indicated Angle

ALL

0-96%

0%

APP Sensor 1

TAC

Volts

1.02 Volts

APP Sensor 1 Indicated Position

TAC

%

0%

APP Sensor 2

TAC

Volts

4.04 Volts

APP Sensor 2 Indicated Position

TAC

%

0%

APP Sensor 1 and 2

TAC

Agree/Disagree

Agree

APP Sensors

TAC

%

0%

BARO

ED, EVAP, FT, HO2S, ID, IND

kPa

65-104 kPa/ Varies w/Altitude

BPP Circuit Signal

TAC

Applied/Released/ Invalid

Released

Calc. TWC Temp

FT, MF

°C/°F

800-1,000°F

Catalytic Converter Protection Active

FT, HO2S

Yes/No

No

CKP Active Counter

ID

Counts

Varies

CKP Resync Counter

ID

Counts

0

CKP Sensor

ID

RPM

600-700

CMMD. A/F Equivalence Ratio

ED, FT, IND, HO2S

Ratio

1.0:1

CMP Sensor

CMP, ID, MF

RPM

Varies

Cold Start-Up

ED, EVAP

Yes/No

Varies

CPP Switch

ED, TAC

Applied/Released

Released

Cruise Control Active

ED, TAC

Yes/No

No

Cycles of Misfire Data

MF

0-100 Counts

Varies

Cyl. 1 IC Circuit Status

MF

OK/Incomplete/ Short B+/ Short Ground/ Short Open

OK

Cyl. 2 IC Circuit Status

MF

OK/Incomplete/ Short B+/ Short Ground/ Short Open

OK

Cyl. 3 IC Circuit Status

MF

OK/Incomplete/ Short B+/ Short Ground/ Short Open

OK

Cyl. 4 IC Circuit Status

MF

OK/Incomplete/ Short B+/ Short Ground/ Short Open

OK

Cyl. 1 Inj. Circuit Status

MF

OK/Incomplete/ Short B+/ Short Ground/ Short Open

OK

Cyl. 2 Inj. Circuit Status

MF

OK/Incomplete/ Short B+/ Short Ground/ Short Open

OK

Cyl. 3 Inj. Circuit Status

MF

OK/Incomplete/ Short B+/ Short Ground/ Short Open

OK

Cyl. 4 Inj. Circuit Status

MF

OK/Incomplete/ Short B+/ Short Ground/ Short Open

OK

Decel Fuel Cutoff

ED, FT, HO2S

Active/Inactive

Inactive

Desired Exh. CMP

CMP

Degrees

0

Desired Idle Speed

CMP, ED, EVAP, TAC

RPM

PCM Controlled

Desired Int. CMP

CMP

Degrees

Distance Since DTC Cleared

ED

km/h /mph

Varies

EC Ignition Relay Circuit Status

TAC

OK/Incomplete/ Short B+/ Short Ground/ Short Open

Incomplete

EC Ignition Relay Command

ED, TAC

ON/OFF

ON

EC Ignition Relay Feedback Signal

ED, TAC

Volts

12-15 Volts

ECT Sensor

ALL

-40 to -40°C (+151 to +303°F)

88-105°C (190-221°F)

Engine Load

ALL

0-100%

23-24% @ Idle

Engine Oil Life Remaining

CMP

%

Varies

Engine Oil Pressure Switch

CMP, ED, MF

OK/Low

OK

Engine Oil Temp Calculated

CMP

Degrees

Varies

Engine Run Time

ALL

Hrs, Min, Sec

Varies

Engine Speed

ALL

0-10,000 RPM

500-700 RPM

Engine Off Time

EVAP

HH:MM:SS

Varies

EVAP Fault History

EVAP

No Fault/ Excess Vacuum/ Purge Valve Leak/ Small Leak/ Weak Vacuum/ No Test Result

No Fault

EVAP Purge Solenoid Command

ED, EVAP, FT, HO2S

0-100%

10-30%

EVAP Purge Solenoid Circuit Status

EVAP

OK/Incomplete/ Short B+/ Short Ground/ Short Open

OK

EVAP Vent Solenoid Command

ED, EVAP

Not Venting/Venting

Venting

EVAP Vent Solenoid Status

EVAP

OK/Incomplete/ Short B+/ Short Ground/ Short Open

Incomplete

Exh. CMP Active Counter

CMP, ID

Counts

0-250

Exh. CMP Angle

CMP

Degrees

Exh. CMP Command

CMP

%

0%

Exh. CMP Solenoid Circuit Status

CMP

OK/ Incomplete/ Short B+/ Short Ground/ Short Open

Incomplete

Exh. CMP Variance

CMP

Degrees

Fuel Level Sensor

EVAP

Volts

1-2 Volts

Fuel Pump Relay Circuit Status

ED

OK/ Incomplete/ Short B+/ Short Ground/ Short Open

Incomplete

Fuel Tank Level Remaining

ED, EVAP, FT, MF

0%

Varies

Fuel Tank Pressure Sensor

EVAP

mm/Hg / In H2O

-1 to +1

Fuel Tank Pressure Sensor

EVAP

Volts

1.5 Volts

Fuel Tank Rated Capacity

EVAP

Liters

62.4

Fuel Trim Cell

ED, FT

Counts

16, 17, 21

Fuel Trim Learn

FT

Enable/Disable

Enabled

Fuel Trim System

FT

Disabled/ Enabled/ Run purge test

--

Fuel Trim System Test State

FT

Monitoring

Varies

Fuel Volatility

EVAP, FT

Low/ Med/ High

Low

HO2S 1

ED, EVAP, FT, HO2S, IND

mV

10-1,000 mV and Varying

HO2S 1 Heater

HO2S

Amps

Varies

HO2S 1 Heater Circuit Status

HO2S

OK/ Incomplete/ Short B+/ Short Ground/ Short Open

OK

HO2S 1 Heater Command

HO2S

ON/ OFF

ON

HO2S 1 Heater Command

TAC

%

98%

HO2S 2

ED, FT, HO2S

mV

10-1,000 mV and Varying

HO2S 2 Heater

HO2S

Amps

Varies

HO2S 2 Heater Circuit Status

HO2S

OK/ Incomplete/ Short B+/ Short Ground/ Short Open

OK

HO2S 2 Heater Command

HO2S

ON/ OFF

ON

HO2S 2 Heater Command

TAC

%

98%

Hot Open Loop

FT, HO2S

Active/Inactive

Inactive

IAT Sensor

ALL

-40 to +151°C (-40 to +303°F)

Depends on ambient temperature

Ignition Accessory Signal

ED, TAC

On/Off

Off

Ignition 1 Signal

ALL

0-25 volts

11.5-14.5 Volts

Injector 1 Disabled Due to Misfire

MF

Yes/ No

No

Injector 2 Disabled Due to Misfire

MF

Yes/ No

No

Injector 3 Disabled Due to Misfire

MF

Yes/ No

No

Injector 4 Disabled Due to Misfire

MF

Yes/ No

No

Int. CMP Active Counter

CMP, ID

Counts

0-250

Int. CMP Angle

CMP

Degrees

0%

Int. CMP Command

CMP

%

0%

Int. CMP Solenoid Circuit Status

CMP

OK/ Incomplete/ Short B+/ Short Ground/ Short Open

Incomplete

Int. CMP Variance

CMP

Degrees

0%

Intake Manifold Pressure

ED, FT, IND

kPa

55-65 kPa

Injector PWM

ED, FT, HO2S, MF

Milliseconds

2-6 ms

Knock Detected Cyl. 1

ID

Yes/No

No

Knock Detected Cyl. 2

ID

Yes/No

No

Knock Detected Cyl. 3

ID

Yes/No

No

Knock Detected Cyl. 4

ID

Yes/No

No

Knock Retard

ID

Degrees

Long Term FT

ED, EVAP, FT, HO2S

%

Near 0%

Long Term Fuel Trim Test Avg.

FT

Counts

0.95-1

Long Term Fuel Trim Test Avg. w/o Purge

FT

Counts

0.95-1

Loop Status

ED, EVAP, FT, HO2S

Open/Closed

Closed

MAF Performance Test

FT, IND, TAC

OK/ Fault

OK

MAF Sensor

IND

Hz

1,800-2,400

MAF Sensor

ALL

g/s

3-6g/s

MAP Performance Test 1

FT, MAP, IND, TAC

OK

OK

MAP Performance Test 2

FT, IND, TAC

OK/ Fault

OK

MAP Sensor

IND

Volts

1-2 Volts

MAP Sensor

ALL

kPa

20-48 kPa

MIL Circuit Status

ED

OK/ Incomplete/ Short B+/ Short Ground/ Short Open

Incomplete

MIL Command

ED

Off/On

Off

MIL Requested By DTC

ALL

Yes/No

No

Misfire Current Cyl #1

MF

Counts

0

Misfire Current Cyl #2

MF

Counts

0

Misfire Current Cyl #3

MF

Counts

0

Misfire Current Cyl #4

MF

Counts

0

Misfire History Cyl #1

MF

Counts

0

Misfire History Cyl #2

MF

Counts

0

Misfire History Cyl #3

MF

Counts

0

Misfire History Cyl #4

MF

Counts

0

PNP Switch

ED

Park/ Net/ In Gear

Varies

Power Enrichment

ED, FT, HO2S, MF

Active/Inactive

Inactive

Reduced Engine Power

TAC

Active/Inactive

Inactive

Short Term Fuel Trim Test Avg.

FT

Counts

0.95-1

Short Term FT

ED, EVAP, FT, HO2S

%

Near 0%

Spark

ED, FT, HO2S, ID, IND, MF

Degrees

5-20°

Start Up ECT

EVAP, HO2S

°C/°F

Varies

Start Up IAT

EVAP, HO2S

°C/°F

Varies

TAC Forced Engine Shutdown

TAC

Yes/No

No

TAC Motor

TAC

Enabled/Disabled

Enabled

TAC Motor Command

TAC

%

20%

TCC/Cruise Brake Pedal Switch

ED, TAC

Applied/Released

Released

TCS Torque Delivered Signal

TAC

%

0%

TCS Torque Request Signal

TAC

%

0%

Torque Management Spark Retard

ID

Degrees

Total Knock Retard

ID

Degrees

Total Misfire Count

MF

Count

0

TP Desired Angle

TAC

%

4%

TP Indicated Angle

ALL

%

4.2%

TP Performance Test

FT, IND, TAC

Active/Inactive

Inactive

TP Sensor 1

TAC

0-5 Volts

4.24 Volts

TP Sensor 1 Indicated Position

TAC

%

4%

TP Sensor 1 Learned Minimum

TAC

Volts

0.55 Volts

TP Sensors 1 and 2

TAC

Agree/Disagree

Agree

TP Sensor 2

TAC

0-100%

4%

TP Sensor 2

TAC

0-5 Volts

0.43 Volts

TP Sensor 2 Indicated Position

TAC

%

4%

TP Sensor 2 Learned Minimum

TAC

Volts

0.57 Volts

Vehicle Speed Sensor

ALL

km/h (mph)

0

Warm-ups Since DTC Cleared

ED

Counts

Varies

Warm-ups Without Emission Faults

ED

Counts

Varies

Warm-ups Without Non-Emission Faults

ED

Counts

Varies

Wide Open Throttle

TAC

Yes/No

No