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.

ED: Engine Data 1 List

EVAP: EVAP Data

FT: Fuel Trim Data List

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

A/C Relay Command

ED, MF

On/Off

Off

A/C Request

MF

Yes/No

No

Air Fuel Ratio

ED, FJ, HO2S

Ratio

14.7:1

APP Indicated Angle

ED, EVAP, FJ, HO2S, ID, MF, TAC

0-96%

0%

APP Sensor 1

TAC

%/Volts

0%/1.02 Volts

APP Sensor 2

TAC

%/Volts

0%/4.04 Volts

APP Sensor 1 and 2

TAC

Agree/Disagree

Agree

APP Sensor 1 Circuit

TAC

--

--

APP Sensor 2 Circuit

TAC

--

--

BARO

ED, EVAP, FT, HO2S, ID

kPa

65-104 kPa/ Varies w/Altitude

Catalytic Converter Protection Active

FT, HO2S

--

--

CKP Active Counter

ID

1-250

9-250

CMP Active Counter

ID

Counts

Varies

CMP Sensor

ED, ID, MF

RPM

RPM

Cold Start-Up

ED, EVAP

Varies

Varies

Crank Request Signal

Eng 3

Yes/No

No

Cruise Control Active

TAC

Yes/No

No

Cycles of Misfire Data

MF

0-100 Counts

Varies

Decel Fuel Cutoff

ED, FT, HO2S

--

--

Desired Idle Speed

ED, EVAP, TAC

RPM

PCM Controlled

EC Ignition Relay Feedback

ED

Volts

Volts

EC Ignition Relay Feedback

TAC

Volts

Volts

ECT Sensor

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

-40 to -40°C (+151 to +303°F)

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

Engine OFF Time

EVAP

--

--

Engine Load

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

0-100%

23-24% @ Idle

7-42% @ 2500 RPM

Engine Oil Pressure Switch

ED, MF

OK/Low

OK

Engine Run Time

ED, EVAP, HO2S, ID, MF, TAC

Hrs, Min, Sec

Varies

Engine Speed

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

0-10,000 RPM

500-700 RPM

EVAP Fault History

EVAP

--

--

EVAP Purge Solenoid Command

ED, EVAP, FT

0-100%

10-30%

EVAP Vent Solenoid Command

ED, EVAP

Not Venting/Venting

Venting

Fuel Tank Level Remaining

ED, EVAP, MF

%

%

Fuel Tank Pressure Sensor

ED, EVAP

mm/Hg / In H2O

Varies

Fuel Tank Pressure Sensor

EVAP

mm/Hg / In H2O/Volts

Varies

Fuel Trim Cell

ED, EVAP, FT

0-23

16, 17, 21

Fuel Trim Learn

ED, EVAP, FT

--

--

Fuel Level Sensor

EVAP

0-100%

Varies

Fuel Pump Relay Command

ED

On/Off

On

HO2S 1

ED, EVAP, FT, HO2S

mV

10-1,000 mV and Varying

HO2S 2

ED, FT, HO2S

mV

10-1,000 mV and Varying

HO2S 1 Heater Current

HO2S

Amps

Varies

HO2S 2 Heater Current

HO2S

Amps

Varies

Hot Open Loop

FT, HO2S

--

--

IAT Sensor

ED, EVAP, FT, ID, MF

-40 to +151°C (-40 to +303°F)

Depends on ambient temperature

Ignition 1 Signal

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

0-25 volts

11.5-14.5 Volts

Initial Brake Apply Signal

TAC

ON/OFF

ON/OFF

Initial Brake Supply Signal

ED

--

--

Injector PWM

FT, MF

Milliseconds

2-6 ms

Knock Retard

ID

°

°

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

Hz

Hz

MAF Sensor

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

g/s

Varies

MAP Sensor

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

kPa

20-48 kPa

Medium Resolution Resync Counter

ID

Counts

0

MIL Command

ED, EVAP, ID

Off/On

Off

MIL Requested By DTC

ED, EVAP, ID

--

--

Mileage Since DTC Clear

ED

M/Km

M/Km

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

PCM Reset

ED, EVAP, ID

--

--

Power Enrichment

ED, FT, HO2S, MF

Active/Inactive

Inactive

Reduced Engine Power

TAC

Active/Inactive

Inactive

Reference Voltage 1 Signal

ED, EVAP, ID, TAC

Volts

5.03 V

Reference Voltage 2 Signal

ED, EVAP, ID, TAC

Volts

Volts

Short Term FT

ED, EVAP, FT, HO2S

%

Near 0%

Short Term FT Avg

FT

%

%

Spark

ED, FT, HO2S, ID, MF

Degrees

11-20°

Start Up ECT

EVAP, FT

°C/°F

Varies

Start Up IAT

EVAP, FT, HO2S

°C

°C

Stop Cam Pedal Switch

TAC

ON/OFF

ON/OFF

Total Misfire Count

MF

--

--

TP Desired Angle

TAC

%

4.2%

TP Sensor Learned Minimum

TAC

Volts

Volts

Torque Request Signal

TAC

N·m

Varies

Torque Delivered Signal

TAC

N·m

Varies

TP Indicated Angle

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

%

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

Active/Inactive

Inactive

TWC Temperature Calculated

MF

C/F

350°C

Vehicle Speed Sensor

ED, EVAP, HO2S, ID, MF, TAC

km/h

mph

0

Warm-ups w/o Non-Emmisons Faults

ED

--

--

Warm-ups w/o Emmisons Faults

ED

--

--