GM Service Manual Online
For 1990-2009 cars only

The Engine Scan Tool Data List contains all of the 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 are determined:

    • The Powertrain On-Board Diagnostic System Check is completed.
    • No diagnostic trouble codes (DTCs) are present.
    • The 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 from a normally running engine.

Important: A scan tool that displays faulty data should not be used. Any scan tool concern 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 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:

Engine Data1: The engine data 1 list

Catalyst Data: The exhaust catalyst data

EGR Data: The exhaust recirculation valve data

EVAP Data: The evaporative emissions data

IPC Data: The instrument panel cluster data

HO2S Data: The heated oxygen sensor data

Misfire Data: The cylinder misfire data

AIR Data: The air injection reaction data

ODD Data: The output driver data

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Engine Idling/Radiator Hose Hot/Closed Throttle/Park or Neutral/Closed Loop/Accessories Off/Brake Pedal Released

3X Crank Sensor

Misfire

RPM

Varies

24X Crank Sensor

Eng 1, Misfire

RPM

Varies

1-2 Sol.

ODD

OK/Fault/Invalid State

OK

2-3 Sol.

ODD

OK/Fault/Invalid State

OK

Abuse Management

Misfire

Active/Inactive

Inactive

A/C High Side Pressure

Eng 1

Volts/PSI

Varies

A/C Off for WOT

Eng 1

Yes/No

No

A/C Relay

ODD

OK/Fault/Invalid State

OK

A/C Request

Eng 1, EGR, Misfire

Yes/No

No

A/C Pressure Disable

Eng 1

Yes/No

No

Actual EGR Position

Eng 1, EGR, Misfire

Percent

0

Air Fuel Ratio

AIR, Cat, HO2S

Ratio

14.2:1 - 14.7:1

Air Active Test Inhibit

AIR

Yes/No

--

Air Active Test Air Injection

AIR

Yes/No

--

Air Diagnostic Complete

AIR

Yes/No

--

Air Passive Test 1 Pass

AIR

Yes/No

--

Air Passive Test 2 Fail

AIR

Yes/No

--

Air Passive Test Passed

AIR

Yes/No

--

Air Passive Test Inhibit

AIR

Yes/No

--

Air Passive Test In Progress

AIR

Yes/No

--

Air Pump Relay

Eng 1, AIR, HO2

On/Off

Off

Air Pump Relay

ODD

OK/Fault/Invalid

Fault

Air Solenoid

AIR, ODD

OK/Fault/Invalid

Fault

Air Solenoid

Eng 1, HO2S, AIR

On/Off

Off

BARO

Eng 1, EGR, EVAP, Cat

kPa/volts

65-110 kPa / 3.5-4.5 volts

Brake Switch

Eng 1

Applied/Released

Released

CMP Sensor Signal Present

Eng 1, Misfire

Yes/No

Yes

Commanded A/C

Eng 1, Cat, Misfire, EGR

On/Off

Off

Commanded Fuel Pump

Eng 1

On/Off

On

Commanded Gen

IPC

On/Off

On

Commanded Starter

Eng 1

Enabled/Disabled

Disabled

Cruise Mode

Eng 1

On/Off

Off

Cruise Inhibit Signal Command

Eng 1

On/Off

ON

Cruise Inhibited

ODD

OK/Fault/Invalid State

OK

Current Gear

Cat, EGR

Transmission Gear Position

Park (1)

Cycles Of Misfire Data

Misfire

Counts

0-99

Cyl. 1-6 Injector CKT History

ODD

OK/Stuck Low (open)/Stuck High/Fault

OK

Cyl. 1-6 Injector CKT Status

ODD

OK/Stuck Low (open)/Stuck High

OK

Decel Fuel Mode

EGR, HO2S, Misfire,

Active/Inactive

Inactive

Desired EGR Position

Eng 1, EGR, Misfire

Percent

0

Desired Idle Speed

Eng 1

RPM

PCM Controlled (varies)

Driver Module 1 Status

ODD

Enabled/Off-High Volts/Off High Temp/Invalid State

Enabled

Driver Module 2 Status

ODD

Enabled/Off-High Volts/Off High Temp/Invalid State

Enabled

Driver Module 3 Status

ODD

Enabled/Off-High Volts/Off High Temp/Invalid State

Enabled

Driver Module 4 Status

ODD

Enabled/Off-High Volts/Off High Temp/Invalid State

Enabled

ECT

Eng 1, AIR, EGR, EVAP, Cat, HO2S, Misfire

°C/°F

Varies

EGR Closed Val. Pintle Pos.

EGR

Volts

0.14-1.0

EGR Duty Cycle

EGR, Eng 1

Percent

0

EGR Feedback

EGR

Volts

0.14-1.0

EGR Flow Test Count

EGR

Counts

0-10

EGR Position Error

EGR

Percent

0-100

Engine Load

Eng 1, Cat, Misfire, EGR, EVAP, AIR

Percent

2-10

Engine Run Time

Eng 1, EVAP, Cat, EGR, AIR, HO2S

Hr: Min: Sec

Varies

Engine Speed

Eng 1, EGR, EVAP, Cat, HO2S, Misfire,

RPM

Varies

Engine Oil Level

IPC

OK/Low

OK

Engine Oil Life

IPC

Percent

0-100

Engine Oil Pressure

IPC

OK/Low/High

OK

EVAP Canister Purge

EVAP, HO2S, Eng 1, AIR

Percent

Low and Varying

EVAP Fault History

EVAP

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

No Fault

EVAP Purge Sol.

ODD, EVAP

OK/Fault/Invalid State

OK

EVAP Vent Sol.

Eng 1, HO2S, EVAP

Open/Closed

Open

EVAP Vent Sol.

EVAP, ODD

OK/Fault/Invalid State

OK

Fans High Speed

Eng 1, Cat

On/Off

Off

Fans Low Speed

Eng 1, Cat

On/Off

Off

FC Relay 1

ODD

OK/Fault/Invalid State

OK

FC Relay 2 and 3

ODD

OK/Fault/Invalid State

OK

Fuel Level

EVAP, IPC

Percent

0-100

Fuel Pump CKT History

ODD

OK/Stuck Low (open)/Stuck High/Fault

OK

Fuel Pump CKT Status

ODD

OK/Stuck Low (open)/Stuck High/Fault

OK

Fuel Tank Pressure

EVAP

in H2O/ volts

Varies

Fuel Trim Cell

Eng 1, Cat, AIR

0-4

0

Fuel Trim Learn

Eng 1, Cat, EVAP

Enabled/Disabled

Enabled

HO2S Sensor 1

Eng 1, HO2S, Cat

Ready/Not Ready

Ready

HO2S Sensor 1

Eng 1, Cat, HO2S, Misfire, AIR

Millivolts

0-1000 and Varying

HO2S Sensor 2

Eng 1, HO2S, Cat

Millivolts

0-1000 and Varying

HO2S X Counts

HO2S, Eng1

Counts

Varies

Hot Open Loop

EGR, Cat

Active/Inactive

Inactive

Hot Mode

Misfire

On/Off

Off

IAC Position

Eng1, Cat

Counts

Varies

IAT

Eng 1, EVAP, Cat, HO2S, EGR, AIR

°C/°F

Varies

Ignition 1

Eng 1, EGR, Misfire, IPC, Cat, HO2S, AIR

Volts

Varies

Ignition Mode

Eng 1

IC/Bypass

IC

Injector Pulse Width

Eng 1, Cat, Misfire, HO2S

Milliseconds

Varies (1.5-3.5)

Knock Retard

Eng 1, EGR

Degrees

0

Long Term FT

Eng 1, EVAP, HO2S, AIR

Percent

0

Loop Status

Eng 1, Cat, HO2S, EVAP, EGR, AIR

Open/Closed

Closed

MAF

Eng 1, Cat, HO2S, EGR, EVAP, AIR, Misfire

Grams per Second

MAF Frequency

Eng 1

Hz

1200-3000 (depends on altitude and engine load)

MAP

Eng 1, EGR, EVAP, Cat

kPa/volts

20-48 kPa/ 0.75-2 volts (depends on altitude)

MIL

IPC

On/Off

Off

MIL

ODD

OK/Fault/Invalid State

OK

Misfire Current Cyl. 1-6

Misfire

Counts

0

Misfire History Cyl. 1-6

Misfire

Counts

0

Non-Volatile Memory

Eng 1, EVAP, IPC, AIR EGR, Cat, HO2S, Misfire, AIR, ODD

Pass/Fail

Pass

Power Enrichment

Eng 1, Cat, EGR, HO2S, Misfire,

Active/Inactive

Inactive

Short Term FT

Eng 1, AIR, HO2S

Percent

0-10

Spark

Eng 1, Misfire

Degrees

20 (varies)

Start Up ECT

EVAP, HO2S, Cat, AIR

°C/°F

Varies

Start Up IAT

HO2S, Cat, AIR, EVAP

°C/°F

Varies

Starter Enable Relay

ODD

Ok/Fault/Invalid State

Ok

TCC Engaged

Eng 1, EGR, Misfire

Engaged/Disengaged

Disengaged

TCC Sol.

ODD

OK/Fault/Invalid State

OK

Total Misfire Current Count

Misfire

Counts

0

Total Misfire Failures

Misfire

Counts

0

Total Misfire Passes Since First Fail

Misfire

Counts

0

TP Sensor

Eng 1, EGR, Cat, HO2S

Volts

0.20-0.74

TP Angle

Eng 1, EGR, Cat, HO2S, Misfire, EVAP, AIR

Percent

0

Traction Control

Eng 1, Misfire

Active/Inactive

Inactive

Traction Control Desired Torque

Eng 1

Percent

100

Traction Control Torque

Eng 1

Percent

Varies by engine load and vehicle speed

Transmission Range

Eng 1, Cat, EGR

Transmission Gear Position

Park

TR Switch A

Eng 1

Low/High

Low

TR Switch B

Eng 1

Low/High

High

TR Switch C

Eng 1

Low/High

High

TR Switch Up

Eng 1

Low/High

Low

TWC Protection

Cat

Active/Inactive

Inactive

Vehicle Speed

Eng 1, EGR, Cat, Misfire, EVAP

MPH / Km/h

0

VTD Fuel Disable

Eng 1

Active/Inactive

Inactive