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 in Vehicle DTC Information 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

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, TAC

On/Off

Off

Air Fuel Ratio

ED, FT, HO2S

Ratio

14.7:1

APP Indicated Angle

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

0-96%

0%

APP Sensor 1

TAC

%/Volts

0%/1.02 Volts

APP Sensor 1

TAC

Degrees

0%

APP Sensor 2

TAC

%/Volts

0%/4.04 Volts

APP Sensor 2

TAC

Degrees

0%

APP Sensor 1 and 2

TAC

Agree/Disagree

Agree

APP Sensor 1 Circuit

TAC

OK/Fault

OK

APP Sensor 2 Circuit

TAC

OK/Fault

OK

BARO

ED, EVAP, FT, HO2S, ID

kPa

65-104 kPa/ Varies w/Altitude

Catalytic Converter Protection Active

FT, HO2S

Yes/No

No

CKP Active Counter

ID

1-250

9-250

CKP Resync Counter

ID

Counts

--

CKP Sensor

ED, ID

RPM

--

Clutch Pedal Switch 2

ED, TAC

--

--

Cold Start-Up

ED, EVAP

Varies

Varies

Cycles of Misfire Data

MF

0-100 Counts

Varies

Decel Fuel Cutoff

ED, FT, HO2S

Active/Inactive

Inactive

Desired Idle Speed

ED, EVAP, TAC

RPM

PCM Controlled

Engine OFF Time

EVAP

--

--

ECM Reset

ED, EVAP, ID

--

--

ECT Sensor

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

-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 Level Switch

ED

--

--

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 Purge Solenoid Command

ED, EVAP, FT, HO2S

0-100%

10-30%

EVAP Vent Solenoid Command

ED, EVAP

Not Venting/Venting

Venting

Fuel Tank Level Remaining

ED, EVAP, MF

%

Varies

Fuel Tank Level Remaining

ED

Liters

Varies

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

Able/Disable

Disabled

Fuel Pump Relay Command

ED, FT

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, HO2S, TAC

-40 to +151°C (-40 to +303°F)

Depends on ambient temperature

Ignition Accessory Signal

ED, TAC

On/Off

Off

Ignition 1 Signal

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

0-25 volts

11.5-14.5 Volts

Injector PWM

FT, HO2S

Milliseconds

2-6 ms

Long Term FT

ED, EVAP, FT, HO2S

%

Near 0%

Loop Status

ED, EVAP, FT, HO2S

Open/Closed

Closed

MAF Sensor

ED, EVAP, FT, HO2S

Hz

Hz

MAF Sensor

ED, EVAP, FT, HO2S, ID, TAC

g/s

Varies

MAP

ED

Volts

--

MAP Sensor

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

kPa

20-48 kPa

MIL Command

ED, EVAP, ID

Off/On

Off

MIL Requested By DTC

ED, EVAP, ID

--

--

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

Power Enrichment

ED, FT, HO2S, MF

Active/Inactive

Inactive

Reduced Engine Power

TAC

Active/Inactive

Inactive

Short Term FT

ED, EVAP, FT, HO2S

%

Near 0%

Spark

ED, FT, HO2S, ID, MF

Degrees

11-20°

Start Up ECT

EVAP, FT, HO2S

°C/°F

Varies

Start Up IAT

EVAP, FT, HO2S

°C/°F

Varies

TAC Forced Engine Shutdown

TAC

--

--

TAC Motor

TAC

--

--

TCC Cruise Brake Pedal

ED, TAC

--

--

Total Knock Retard

ID

Agrees

--

Total Misfire Count

MF

Count

0

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, FT

C/F

350°C

Vehicle Speed Sensor

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

km/h

mph

0

Wide Open Throttle

TAC

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