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

COOL: Cooling/HVAC Data

ED: Engine Data

EVAP: EVAP Data

FSD: Fuel System Data

FT: Fuel Trim Data List

I/M: I/M Data

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

Typical Values

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

5-Volt Reference 1 Circuit Status

COOL, EVAP, FSD, TAC, IND, ID

OK / Fault

OK

5-Volt Reference 2 Circuit Status

EVAP, COOL, FSD, TAC, IND, ID

OK / Fault

OK

5-Volt Reference 3 Circuit Status

EVAP, COOL, FSD, ID, IND, TAC

OK / Fault

OK

A/C Disengage 1 History

COOL

None / Battery Voltage / High Pressure / Engine Speed

None

A/C Disengage 2 History

COOL

None / Battery Voltage / High Pressure / Engine Speed

None

A/C Disengage 3 History

COOL

None / Battery Voltage / High Pressure / Engine Speed

None

A/C Disengage 4 History

COOL

None / Battery Voltage / High Pressure / Engine Speed

None

A/C Disengage 5 History

COOL

None / Battery Voltage / High Pressure / Engine Speed

None

A/C Disengage 6 History

COOL

None / Battery Voltage / High Pressure / Engine Speed

None

A/C Disengage 7 History

COOL

None / Battery Voltage / High Pressure / Engine Speed

None

A/C Disengage 8 History

COOL

None / Battery Voltage / High Pressure / Engine Speed

None

A/C High Side Pressure Sensor

COOL

Volts

0.96

A/C High Side Pressure Sensor

COOL

kPa / psi

518 kPa / 75 psi

A/C Off For WOT

COOL

Yes / No

No

A/C Pressure Disable

COOL

Yes / No

No

A/C Relay Circuit Status

COOL

OK / Incomplete / Short B+ / Short GND / Open

Incomplete

A/C Relay Command

COOL, MF, IND, TAC

On / Off

Off

A/C Relay Command

ED, MF

On / Off

Off

A/C Request Signal

COOL

Yes / No

No

Actual Fuel Rail Pressure

ED, FSD, FT

MPa

3.0-6.0

Air Flow Calculated

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

g/s

Varies

Air Fuel Ratio

ED

Ratio

14.7:1

APP Indicated Angle

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

%

0

APP Sensor 1

TAC

Volts

--

APP Sensor 1 and 2

TAC

Agree / Disagree

Agree

APP Sensor 2

TAC

Volts

0.47

APP Sensors

TAC

%

0

Aux. Vac. Pump Relay Circuit Status

IND

OK / Fault / Indeterminate

Indeterminate

Aux. Vac. Pump Relay Command

IND

On / Off

OFF

Average Injector PWM

FT

ms

1

BARO

ID, FT, ED, EVAP, FSD, IM, IND, HO2S

kPa

Varies with altitude

BARO Sensor

IND

Volts

3

Boost Pressure Sensor

FT, IND

kPa

98

Boost Pressure Sensor

IND

Volts

1.78

Brake Booster Pressure Sensor

ED

kPa

26

Brake Pedal Signal Status

ED, TAC

Valid / Invalid

Valid

Calc. TWC Temp.

MP, FT

°C (°F)

408°C (766°F)

Calculated ECT-Closed Loop Fuel Control

ED, COOL

°C (°F)

Varies

Calculated ECT-Thermostat Diagnosis

ED, COOL

°C (°F)

Varies

Catalyst Monitor Complete This Ignition

I/M

Yes / No

No

Catalyst Monitor Enabled This Ignition

I/M

Yes / No

Yes

Catalytic Converter Protection Active

FT, HO2S

Yes / No

No

CKP Active Counter

ID

Counts

Varies

CKP Resync Counter

ID

Counts

Varies

Cmmd. A/F Equivalence Ratio

FSD, FT, IND, HO2S

Ratio

1.0:1

CMP Sensor

CMP, ID, MF

RPM

0

Cold Startup

EVAP, ED, IM

Yes / No

Varies

Control Module Voltage Signal

CMP, FSD, IM, ID, EVAP, ED, COOL, MF, FT, IND, HO2S

Volts

14.1

Cooling Fan Motor Command

COOL

%

0

CPP Switch (If equipped)

ED, IM, TAC

Applied / Released

Released

Cruise Control Active

ED, TAC

Yes / No

No

Cycles of Misfire Data

MF

Counts

0-1999

Cylinder 1 IC Circuit Status

MF

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

OK

Cyliner 1 Knock Retard

ID

Degrees

Varies

Cyliner 2 Knock Retard

ID

Degrees

Varies

Cyliner 3 Knock Retard

ID

Degrees

Varies

Cyliner 4 Knock Retard

ID

Degrees

Varies

Cylinder 1 Injector Circuit Status

MF

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

OK

Cylinder 2 IC Circuit Status

MF

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

OK

Cylinder 2 Injector Circuit Status

MF

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

OK

Cylinder 3 IC Circuit Status

MF

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

OK

Cylinder 3 Injector Circuit Status

MF

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

OK

Cylinder 4 IC Circuit Status

MF

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

OK

Cylinder 4 Injector Circuit Status

MF

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

OK

Decel. Fuel Cutoff

FSD, ED, FT, HO2S

Active / Inactive

Inactive

Desired Exh. CMP

CMP

Degrees

0

Desired Fuel Rail Pressure

FSD, FT

MPa

3.8

Desired HO2S 1

FT, HO2S

Lambda

0.991

Desired HO2S 1

HO2S

Volts

0

Desired Idle Speed

CMP, ED, FSD, TAC, EVAP, IND

RPM

800

Desired Int. CMP

CMP

Degrees

0

Desired TC Boost

IND

kPa

48

Distance Since DTC Cleared

ED

km / miles

Varies

EC Ignition Relay Circuit Status

TAC

OK / Incomplete / Short B+ / Short Gnd / Open

Incomplete

EC Ignition Relay Command

ED

On / Off

On

EC Ignition Relay Feedback Signal

ED, TAC

Volts

14.1

ECT Sensor

IM, ED, FSD, FT, HO2S, EVAP, CMP, COOL

°C (°F)

92°C (197°F)

Engine Load

ED, CMP, EVAP, FSD, FT, HO2S, ID, IND, TAC, COOL, MF

%

15-22

Engine Off EVAP Test Conditions Met

EVAP, IM

Yes / No

Yes

Engine Off Time

ID

HH:MM:SS

Varies

Engine Oil Pressure Switch

ED, MF, CMP

OK / Low

OK

Engine Oil Temperature Calculated

CMP, COOL

°C / °F

87°C /188 °F

Engine Run Time

All

HH:MM:SS

Varies

Engine Speed

All

RPM

700-900

EVAP Fault History

EVAP

No Fault, No Test Result

No Test Result

EVAP Monitor Complete This Ignition

IM

Yes / No

No

EVAP Monitor Enabled This Ignition

IM

Yes / No

No

EVAP Purge Solenoid Circuit Status

EVAP

OK / Incomplete / Short B+ / Short Gnd / Open

OK

EVAP Purge Solenoid Command

EVAP, FT, HO2S

%

0-100

EVAP Vent Solenoid Circuit Status

EVAP

OK / Incomplete / Short B+ / Short Gnd / Open

Incomplete

EVAP Vent Solenoid Command

ED, EVAP

Venting / Not Venting

Varies

Exh. CMP Active Counter

CMP, ID

Counts

255

Exh. CMP Angle

CMP

Degrees

0

Exh. CMP Command

CMP

%

6

Exh. CMP Solenoid Circuit Status

CMP

OK / Incomplete / Short B+ / Short Gnd / Open

OK

Exh. CMP Variance

CMP

Degrees

0

FC Circuit Status

COOL

OK / Incomplete / Short B+ / Short Gnd / Open

Incomplete

FRP Regulator Command

FSD, FT

Degrees

125

Fuel Level Sensor

EVAP, FSD

Volts

Varies

Fuel Pump Relay Circuit Status

FSD, FT

OK / Incomplete / Short B+ / Short Gnd / Open

Fault

Fuel Pump Relay Command

FSD, ED

On / Off

On

Fuel Rail Pressure Sensor

FT, ED

Volts

1.2-1.5

Fuel Tank Level Remaining

ED, FSD, FT, EVAP, MF, IM

%

Varies

Fuel Tank Level Remaining

EVAP, MF, IM

Gallons / Liters

Varies

Fuel Tank Pressure Sensor

EVAP, ED, FSD

mm/Hg / in H2O

Varies

Fuel Tank Pressure Sensor

EVAP

Volts

1.5

Fuel Tank Rated Capacity

EVAP

Gallons / Liters

Varies

Fuel Trim Learn

FT

Enabled / Disabled

Disabled

Fuel Volatility

FT, FSD, EVAP

Low / Moderate / High

Varies

HO2S 1

HO2S, IND, EVAP, ED, FT

Lambda

Varies

HO2S 1 Heater Circuit Status

HO2S

OK / Incomplete / Short B+ / Short Gnd / Open

Incomplete

HO2S 1 Heater Command

HO2S

On / Off

On

HO2S 1 Heater Command

HO2S

%

37

HO2S 1 Sensing Element

HO2S

Ohms

300

HO2S 2

FT, HO2S, ED

Mv

0.795 (Varies)

HO2S 2 Heater Circuit Status

HO2S

OK / Incomplete / Short B+ / Short Gnd / Open

Incomplete

HO2S 2 Heater Command

HO2S

On / Off

On

HO2S 2 Heater Command

HO2S

%

100

HO2S 2 Sensing Element

HO2S

Ohms

0

HO2S Heater Monitor Complete This Ignition

IM

Yes / No

No

HO2S Heater Monitor Enabled This Ignition

IM

Yes / No

Yes

HO2S Sensor 1 Module Signal

CMP, FT, HO2S, MF

Volts

1.47

HO2S/O2S Monitor Complete This Ignition

IM

Yes / No

No

HO2S/O2S Monitor Enabled This Ignition

IM

Yes / No

Yes

IAT Sensor

All

°C (°F)

--

IAT Sensor 2

ED, EVAP, COOL, FT, IND

°C (°F)

15-40

Ignition 0 Signal

ED, TAC

Units

--

Ignition 1 Signal

ED, EVAP

On / Off

On

Ignition Off Time

ED, EVAP, IM

HH:MM:SS

Varies

Initial Brake Apply Signal

IM, TAC

Released / Applied

Released

Inj. 1 Disabled Due to Misfire

MF

Yes / No

No

Inj. 2 Disabled Due to Misfire

MF

Yes / No

No

Inj. 3 Disabled Due to Misfire

MF

Yes / No

No

Inj. 4 Disabled Due to Misfire

MF

Yes / No

No

Injector 1 Command

FT

ms

Varies

Injector 2 Command

FT

ms

Varies

Injector 3 Command

FT

ms

Varies

Injector 4 Command

FT

ms

Varies

Int. CMP Active Counter

CMP, ID

Counts

255

Int. CMP Angle

CMP

Degrees

0

Int. CMP Command

CMP

%

6

Int. CMP Solenoid Circuit Status

CMP

OK, Incomplete, Short B+, Short Gnd / Open

OK

Int. CMP Variance

CMP

Degrees

0

Intake Manifold Pressure

ED, FT, IND

kPa

Varies

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

Varies

KS 1 Signal

ID

Volts

Varies

KS 2 Signal

ID

Volts

Varies

Long Term FT

ED, EVAP, FT, HO2S

%

0

Loop Status Sensor 1

ED, EVAP, FT, HO2S

Open / Closed

Varies

Loop Status Sensor 2

ED, EVAP, FT, HO2S

Open / Closed

Varies

LT FT Idle/Decel.

ED, EVAP, FT, HO2S

%

0

MAF Sensor

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

g/s

2-4

MAF Sensor

IND

Hz

1950

MAP Sensor

IND, FT, ED, TAC, CMP, FSD, EVAP, MF

kPa

30-38

MAP Sensor

IND

Volts

0.67

MIL Circuit Status

ED

OK / Incomplete / Short B+ / Short Gnd / Open

Incomplete

MIL Command

ED

On / Off

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

Moderate Brake Apply Signal

TAC

Applied / Released

Released

PNP Switch

ED

Park / Neutral

Park

Post Inj. Cyl. 1 Command

FT

ms

0

Post Inj. Cyl. 2 Command

FT

ms

0

Post Inj. Cyl. 3 Command

FT

ms

0

Post Inj. Cyl. 4 Command

FT

ms

0

Power Enrichment

ED, FSD, MF, FT

Active / Inactive

Inactive

Reduced Engine Power

TAC

Active / Inactive

Inactive

Short Term FT

ED, EVAP, FT, HO2S

%

0

Spark

HO2S, FT, ED, FSD, IND, MF, COOL, ID

Degrees

Varies

Start Up ECT

EVAP, COOL, IM, HO2S

°C (°F)

Varies

Start Up IAT

ED, FT, IND

°C (°F)

--

Stop Lamp Pedal Switch

IM

Released / Applied

Released

System Power Mode

ED, EVAP

Offawake / Run / Accessory

Run

TAC Forced Engine Shutdown

TAC

Yes / No

No

TAC Motor

TAC

Enabled / Disabled

Enabled

TC Bypass Solenoid Circuit Status

IND

OK, Incomplete, Short B+, Short Gnd / Open

--

TC Bypass Solenoid Command

ID

On / Off

On

TC Wastegate Solenoid Circuit Status

ID, IND

OK, Incomplete, Short B+, Short Gnd / Open

Incomplete

TCS Torque Delivered Signal

ID, TAC

%

0

TCS Torque Request Signal

TAC

%

98

Total Fuel Trim Average

EVAP, ID, HO2S, FT

%

Varies

Total Knock Retard

COOL, ID

Degrees

Varies

Total Misfire

MF

Counts

0

TP Desired Angle

TAC

%

2

TP Indicated Angle

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

%

2-5

TP Sensor 1

TAC

Volts

4.22

TP Sensor 1 Learned Minimum

TAC

Volts

4.31

TP Sensor 2

TAC

Volts

0.76

TP Sensor 2 Learned Minimum

TAC

Volts

0.69

TP Sensors 1 and 2

TAC

Agree / Disagree

Agree

Vehicle Speed Sensor

ALL

kmh / mph

0

Volumetric Efficiency

ID, ED, EVAP, FT, HO2S, CMP, MF, COOL

%

15-22

Warm-ups Since DTC Cleared

ED

Counts

Varies

Wastegate Solenoid Command

IND

%

0

Wide Open Throttle

TAC

Yes / No

No