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:

    • Powertrain On-Board Diagnostic System Check is completed.
    • No Diagnostic Trouble Codes (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 normally running engine.

Important: Altitude, temperature, and humidity, specific to the operating region may cause scan data values to vary. The scan data values may not exactly match those displayed in the typical scan data table. If the scan data values in your area do not fall within the ranges specified, compare your readings to a known good vehicle.

If a scan tool malfunction is suspected, retest the scan tool on another similar vehicle if possible. A malfunctioning scan tool 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. Refer to Symptoms for diagnosis if all values fall within the typical range described in the table.

The column labeled Data List indicates where a parameter is located on the scan tool. Refer to the scan tool operating manual for instructions on how to access the individual data lists. The following is a description of each term listed:

    • Eng 1 = Engine Data 1
    • Eng 2 = Engine Data 2
    • Eng 3 = Engine Data 3
    • FT 1 = Fuel Trim 1 Data List
    • FT 2 = Fuel Trim 2 Data List
    • Misfire = Misfire Data
    • EVAP = EVAP Data
    • Cat = Catalyst Data

Scan Tool Parameter

Units Displayed

Data List*

Cold Key On¹

Cold Idle¹

Hot Idle¹

55 MPH Cruise²

4X Ref. Pulse Counter

Counts

Eng 2

0

8

8

8

# Of Catalyst Mon. Test Completed

Counts

Cat

Varies

Varies

Varies

Varies

Actual EGR Position

%

Eng 1

0

0

0

50

A/C High Side Pressure

Volts

Eng 3

Varies

Varies

Varies

Varies

A/C Relay

Off,On

Eng 2,3

Off

Off

Off

On

A/C Relay Driver

Ok/ Open,Short/ Overcurrent

Eng 3

Ok

Ok

Ok

Ok

Air Fuel Ratio

:1

Eng 2,FT1,2,Cat

Varies

Varies

14.5 to 14.9

14.7

Auto Learn Timer

Active/Inactive

Eng 3

Inactive

Inactive

Inactive

Inactive

BARO

kPa/V

Eng 1,EVAP, Cat

85 to 103 kPa

85 to 103 kPa

85 to 103 kPa

85 to 103 kPa

Calculated Air Flow

gms/sec

Cat

Varies

Varies

Varies

Varies

Calc. Converter Temp.

°C (°F)

FT2, Cat

Varies

Varies

Varies

Varies

Calculated ECT

°C (°F)

EVAP

-40°C(F)

-40°C(F)

-40°C(F)

-40°C(F)

Catalyst EWMA Samples

Counts

Cat

Varies

Varies

Varies

Varies

Catalyst Test Fail Threshold

Seconds

Cat

0.05

0.05

0.05

0.05

Catalyst Test Time Difference EWMA

See Definition

Cat

--

--

--

--

Commanded EGR

%

Eng 1

0

0

0

50

Cruise

Enabled/ Disabled

Eng 3

Disabled

Disabled

Disabled

Enabled

Cruise Enable Driver

Ok/ Open,Short/ Overcurrent

Eng 3

Ok

Ok

Ok

Ok

Cruise Requested

Yes/No

Eng 3

No

No

No

Yes

Current Gear

1,2,3,4

Eng 2

1

1

1

4

Current Octane Level

Counts

Eng 3

93

93

93

93

Current TWC Test Completed

Yes/No

Cat

No

No

Varies

No

Cycles Of Misfire Data

Counts

Mis

0

Varies

Varies

Varies

Delivered Torque Driver

Ok/ Open,Short/ Overcurrent

Eng 3

Ok

Ok

Ok

Ok

Desired Idle Speed

RPM

Eng1,2 FT1,2 Mis, EVAP Cat

0

700 to 1200

650 to 750

720

Desired Torque ABS/TCS

%

Eng 2

100%

100%

100%

100%

Driver #1

Ok, Fault

Eng 3

Ok

Ok

Ok

Ok

Driver 1 Ground

Ok, Fault

Eng 3

Ok

Ok

Ok

Ok

Driver 2 Ground

Ok, Fault

Eng 3

Ok

Ok

Ok

Ok

ECT

°C (°F)

All

-20°C to 50°C

-20°C to 50°C

90°C to 110°C

90°C to 110°C

ECT At Start Up

°C (°F)

Eng 2

Varies

Varies

Varies

Varies

EGR Closed Pintle Pos.

Volts

Eng 1

0.65 to 0.80

0.65 to 0.80

0.65 to 0.80

0.65 to 0.80

EGR Pintle Position

Volts

Eng 1

same as EGR Closed Pintle Pos.

same as EGR Closed Pintle Pos.

same as EGR Closed Pintle Pos.

2.50

Engine Load

%

All

0%

1 to 5

1 to 5

13

Engine Run Time

Hr. / Min. / Sec.

Eng 1,2,3 F1, EVAP Cat

0:00:00

Varies

Varies

Varies

Engine Speed

RPM

All

0

Within 80 RPM of Desired Idle

Within 80 RPM of Desired Idle

1730

Engine Speed At Misfire

RPM

Mis

0

0

0

0

Engine Oil Level

Ok,Low

Eng 2

Ok

Ok

Ok

Ok

Engine Oil Life

%

Eng 2

Varies

Varies

Varies

Varies

Engine Oil Pressure

Ok,Low

Eng 3

Low

Ok

Ok

Ok

EVAP Canister Purge

%

Eng 2,3 EVAP

0%

0%

10 to 20%

Varies

EVAP Purge Solenoid Driver

Ok/ Open,Short/ Overcurrent

Eng 3

Ok

Ok

Ok

Ok

EVAP Tank Vacuum Decay Slope

in. H2O/Sec.

EVAP

less than 0.10

less than 0.10

less than 0.10

less than 0.10

EVAP Test Result

See Definition

EVAP

--

--

--

--

EVAP Test State

See Definition

EVAP

--

--

--

--

EVAP Test Abort Reason

See Definition

EVAP

--

--

--

--

EVAP Vent Sol.

Open, Closed

Eng 3 EVAP

Open

Open

Open

Open

EVAP Vent Valve Driver

Ok/ Open,Short/ Overcurrent

Eng 3

Ok

Ok

Ok

Ok

Extended Travel Brake

Released/ Applied

Eng 1

Released

Released

Released

Released

FC Relay 1

Off,On

Eng 1,3

Off

Off

Varies

Off

FC Relay 2 and 3

Off,On

Eng 1,3

Off

Off

Varies

Off

FP Voltage Feedback

Volts

Eng 1

B+ 2 seconds then 0

Within 1V of battery

Within 1V of battery

Within 1V of battery

Fuel Ctrl. State Bank 1

Normal/ Fault/ Drive Conditions

EVAP

Normal

Normal

Normal

Normal

Fuel Ctrl. State Bank 2

Normal/ Fault/ Drive Conditions

EVAP

Normal

Normal

Normal

Normal

Fuel Pump Relay

On/Off

Eng 1

On 2 seconds then Off

On

On

On

Fuel Tank Pressure

in. H2O/ Volts

EVAP

Varies

Varies

Varies

Varies

Fuel Tank Vapor Press.

in. H2O/Sec.

EVAP

Varies

Varies

Varies

Varies

Fuel Trim Cell

1 to 16

Eng 1

0

16

16

5

Fuel Trim Learn

Disabled/ Enabled

Eng 1

Disabled

Disabled

Enabled

Enabled

Generator PWM

%

Eng 1,3

100%

Varies

Varies

Varies

High Elec. Load

Yes/No

Eng 1,3

No

No

No

No

HO2S Bank 1 Sensor 1

mV

All

70

Varies

Varying

Varying

HO2S Bank 1 Sensor 3

mV

Eng1, F1,2 Cat

70

Varies

600 or more

600 or more

HO2S Bank 2 Sensor 1

mV

All

70

Varies

Varying

Varying

HO2S Warm-Up Bn1 Sen 1

Seconds

F1,2

30 to 50

30 to 50

30 to 50

30 to 50

HO2S Warm-Up Bn1 Sen 3

Seconds

F1

60 to 200

60 to 200

60 to 200

60 to 200

HO2S Warm-Up Bn 2 Sen 1

Seconds

F1

30 to 50

30 to 50

30 to 50

30 to 50

HO2S XCounts Bank 1

Counts

F1,2 Cat

0

Varies

Varies

Varies

HO2S XCounts Bank 2

Counts

F1,2 Cat

0

Varies

Varies

Varies

IAC Position

Counts

Eng 1,2,3 F 1,2 Cat

160

Varies

30 to 80

Varies

IAT

°C (°F)

Eng 1,3 F 1 EVAP, Cat

near outside temp

near outside temp

near outside temp

near outside temp

I/C Mode

ICM/PCM

Eng 1,2

ICM

PCM

PCM

PCM

Ign. Cycle Counter

Counts

Eng 2

Varies

Varies

Varies

Varies

Ignition 0

Volts

Eng 1,3

Within 1V of battery

Within 1V of battery

Within 1V of battery

Within 1V of battery

Ignition 1

Volts

Eng 1,2,3 F 1,2

Within 1V of battery

Within 1V of battery

Within 1V of battery

Within 1V of battery

Ignition 1 Supplement

Ok/ Low

Eng 3

Ok

Ok

Ok

Ok

Injector 1 thru 8 Fault

Yes,No

Eng 3

No

No

No

No

Injector PWM Bank 1

ms

Eng 1, F1, EVAP, Cat

0.0

3.75 to 4.50

3.00 to 3.75

5.0

Injector PWM Bank 2

ms

Eng 1, F1, EVAP, Cat

0.0

3.75 to 4.50

3.00 to 3.75

5.0

IPC Fuel Disable

Active/Inactive

Eng 3

Inactive

Inactive

Inactive

Inactive

Knock Retard

°

Eng 1 Mis

Knock Too Long

Yes/No

Eng 1

No

No

No

No

KS Active Counter

Counts

Eng 1

0

0

0

0

Load At Misfire

%

Mis

0

0

0

0

Loop Status

Open/ Closed

All

Open

Varies

Closed

Closed

Long Term FT Bank 1

%/Counts

Eng 1, F1,2 EVAP, Cat

0% / 128

-25% to 25%

-25% to 25%

-25% to 25%

Long Term FT Bank 2

%/Counts

Eng 1, F1,2 EVAP, Cat

0% / 128

-25% to 25%

-25% to 25%

-25% to 25%

L/R Switch Bank 1 Sen 1

Counts

F2

More than 12

More than 12

More than 12

More than 12

L/R Switch Bank 2 Sen 1

Counts

F2

More than 12

More than 12

More than 12

More than 12

L/R Transition Bn1 Sen1

ms

F1

Varies

Varies

Varies

Varies

L/R Transition Bn2 Sen1

ms

F1

Varies

Varies

Varies

Varies

MAF

gms/sec

All

0.0

9.8 to 11.0

5.0 to 7.0

20 to 28

MAF Frequency

Hz

Eng 3

0

3200

2800

5100

MAP

kPa/V

All except F 2

equal to barometricpressure

30 to 50 kPa

1.50V @ 38 kPa

30 to 50 kPa

1.50V @ 38 kPa

65 / 2.88

MIL

On/Off

Eng 1,3

On

Off

Off

Off

MIL Driver

Ok/ Open,Short/ Overcurrent

Eng 3

Ok

Ok

Ok

Ok

Misfire Current Cyl. # 1 thru 8

Counts

Mis

0

0

0

0

Misfire History Cyl. # 1 thru 8

Counts

Mis

0

0

0

0

Misfire Cycle Delay Counter

Counts

Mis

50

0

0

0

Non-Driven Wheel Speed

km/H (mph)

Eng 2

0--2

0--2

0--2

Within 7 mph of Vehicle Speed

Number Of Failed Emission Misfire Tests Out Of Last 16

Counts

Mis

0

0

0

0

Odometer

km/ miles

Eng 3

Within 25.5 miles of IPC

Within 25.5 miles of IPC

Within 25.5 miles of IPC

Within 25.5 miles of IPC

OSC Test Complete

Yes/No

Cat

No

No

Varies

No

Outside Air Temperature

°C (°F)

Eng 2,3

Varies

Varies

Varies

Varies

PNP

P-N / -ROD21

Eng 1,2,3

P-N

P-N

P-N

-ROD21

Power Enrichment

Inactive/ Active

Eng 2,3 F 1

Inactive

Inactive

Inactive

Inactive

PSP Switch

Normal/Hi Press.

Eng 1 F 1

Normal

Normal

Normal

Normal

Ref. Volts Low

Volts

Eng 2

near 0.00

near 0.00

near 0.00

near 0.00

R/L Status Bank 1 Sen. 1

Rich/Lean

Eng 1 F 1,2

Lean

Varies

Varies

Varies

R/L Status Bank 1 Sen. 3

Rich/Lean

Eng 1 F 1,2

Lean

Varies

Varies

Varies

R/L Status Bank 2 Sen. 1

Rich/Lean

Eng 1 F1,2

Lean

Varies

Varies

Varies

R/L Transition Bn1 Sen1

ms

F1

Varies

Varies

Varies

Varies

R/L Transition Bn2 Sen1

ms

F1

Varies

Varies

Varies

Varies

R/L Switch Bank 1 Sen 1

Counts

F2

More than 12

More than 12

More than 12

More than 12

R/L Transition Bn2 Sen 1

Counts

F2

More than 12

More than 12

More than 12

More than 12

Service Spark Retard

°

Eng 2

Shift Sol. 1 Driver

Ok/ Open,Short/ Overcurrent

Eng 3

Ok

Ok

Ok

Ok

Shift Sol. 2 Driver

Ok/ Open,Short/ Overcurrent

Eng 3

Ok

Ok

Ok

Ok

Shift Sol. Valve 1

Off,On

Eng 2,3

On

On

On

On

Shift Sol. Valve 2

Off,On

Eng 2,3

Off

Off

Off

On

Short Term FT Bank 1

%/Counts

Eng 1 F1,2 EVAP Cat

0% / 128

-5% to 5%

-8% to 8%

-10% to 10%

Short Term FT Bank 2

%/Counts

Eng 1 F 1,2 EVAP Cat

0% / 128

-5% to 5%

-8% to 8%

-10% to 10%

Spark

°

Eng 1 F1 Mis

Varies

Varies

30°

Tachometer Driver

Ok/ Open,Short/ Overcurrent

Eng 3

Ok

Ok

Ok

Ok

TCC Brake Switch

Released/ Applied

Eng 1,2,3

Released

Released

Released

Released

TCC Duty Cycle

%

Eng 2,3

0%

0%

0%

90%

TCC Enable

Yes,No

Eng 2,3

No

No

No

Yes

TCC Slip Speed

RPM

Eng 1,2

0

+15 to +50

+15 to +50

+35

TCC Solenoid Driver

Ok/ Open,Short/ Overcurrent

Eng 3

Ok

Ok

Ok

Ok

TCM Calibration ID

Numeral

Eng 2

Varies

Varies

Varies

Varies

TCM Software ID

Numeral

Eng 2

Varies

Varies

Varies

Varies

Trans. Fluid Temp.

°C (°F)

Eng 2

-20°C to 50°C

-20°C to 50°C

50°C to 130°C

50°C to 130°C

TFP Switch

Park/ Neutral,

Eng 3 F1,2

Park /Neutral

Park /Neutral

Park /Neutral

Park /Neutral

TFP Switch A/B/C

Off/On

Eng 2

Off.On,Off

Off.On,Off

Off.On,Off

Off,On,On

Throttle At Idle

Yes/No

Eng 1 F 1,2

Yes

Yes

Yes

No

Total Misfire Failures Since First Fail

Counts

Mis

0

0

0

0

Total Misfire Passes Since First Fail

Counts

Mis

0

0

0

0

TP Angle

%

Eng 2 EVAP Cat

0%

0%

0%

11%

TP Normalized

%/°

Eng 1

0/0.0°

0/0.0°

0/0.0°

11%/ 11°

TP Sensor

V/°

All

0.55/0.0°

0.55/0.0°

0.55/0.0°

1.05/11°

Traction Control

Active/ Inactive

Eng 2

Inactive

Inactive

Inactive

Inactive

Traction Control Torque

%

Eng 2,3

0%

13 to 18%

8 to 18%

13 to 18%

Transmission Range

P/N, R, D4, D3, D2, L

Eng 3

P/N

P/N

P/N

D4

TR Switch A,B,C,P

High/Low

Eng 3

L,H,H,L

L,H,H,L

L,H,H,L

H,L,L,H

Trans. Oil Life

%

Eng 2

Varies

Varies

Varies

Varies

TWC Stage 1 Started

Yes/No

Cat

No

No

Varies

No

TWC Stage 2 Started

Yes/No

Cat

No

No

Varies

No

TWC Test Enabled

Yes/No

Cat

No

No

Varies

No

TWC Test Initilization Conditions Met

Yes/No

Cat

No

No

Varies

No

Vehicle Speed

km/H (mph)

Eng 1,2,3 F 1,2 EVAP

0

0

0

55 MPH

Vehicle Speed Driver

Ok/ Open,Short/ Overcurrent

Eng 3

Ok

Ok

Ok

Ok

VTD Fuel Disable

Active/Inactive

Eng 3

Inactive

Inactive

Inactive

Inactive

VTD Password

Ok/Incorrect

Eng 3

Ok

Ok

Ok

Ok

VTD Password Learn Mode

Active/Inactive

Eng 3

Inactive

Inactive

Inactive

Inactive

¹For Cold Key On, Cold Idle, and Hot Idle ensure the following driving conditions are met:

    • Vehicle in PARK
    • A/C turned OFF
    • No power steering load
    • All ACC.s OFF
    • Brake pedal released

²For 55 MPH Cruise ensure the following driving conditions are met:

    • Vehicle in Drive 4
    • AC turned ON
    • No power steering load

Record the data after driving for approximately 1 mile.

    • *Eng 1,2,3 = Engine 1,2 or 3
    • *F 1,2, = Fuel Trim 1 or 2
    • *Mis = Misfir
    • *Cat = Catalyst