GM Service Manual Online
For 1990-2009 cars only
Table 1: Engine Data 1
Table 2: Engine Data 2
Table 3: Engine Data 3
Table 4: HO2S Data
Table 5: Misfire Data
Table 6: EVAP Data

Use the scan tool data listed in this table for comparison after the On-Board Diagnostic system check and finding the on-board diagnostics function properly with no diagnostic codes displayed.

The Typical Scan Tool Data Values are an average of display values recorded from normally operating vehicles. The Typical Scan Tool Data Values are intended to represent what a normally functioning system would display. The values you get may vary due to a low battery charge or other reasons. But they should be very close.

Do not use a scan tool that displays faulty data. Report the problem to the manufacturer. The use of a faulty scan tool can result in misdiagnosis and unnecessary parts replacement.

Use only the parameters listed in the tables for diagnosis. If a scan tool reads other parameters, the values are not recommended by General Motors for use in diagnosis. For more description on the values and the use of the scan tool diagnosis the VCM inputs, refer to the applicable diagnosis. If all values are within the range illustrated, refer to Driveability Symptoms.

Scan Tool Data Display

Engine Data 1

Engine at Operating Temp/Engine Idling in Closed Loop/Closed Throttle/Park or Neutral/Accessories OFF

Scan Position

Units Displayed

Typical Data Value

Engine Speed

RPM

600-650 RPM

Desired Idle

RPM

600-650 RPM

Startup ECT

Degrees

Varies

ECT

Degrees

93°C (200°F)

ECT Sensor

Volts

2.0 Volts

Startup IAT

Degrees

Varies

IAT

Degrees

Varies

IAT Sensor

Volts

Varies

Air Fuel Ratio

Ratio

14.7:1

IAC Position

Counts

Varies

Desired IAC

Counts

Varies

TP Sensor

Volts

0.47 Volts

TP Angle

%

0%

MAP

kPa

30-35 kPa

MAP

Volts

1.07-1.31 Volts

BARO

kPa

95 kPa

BARO

Volts

4.58 Volts

Ignition 1

Volts

13.5 Volts

Engine Speed

RPM

600-650 RPM

Long Term FT Bank 1

%

0%

Long Term FT Bank 1

Counts

127 Counts

Long Term FT Bank 2

%

-3%

Long Term FT Bank 2

Counts

123 Counts

Short Term FT Bank 1

%

0%

Short Term FT Bank 1

Counts

128 Counts

Short Term FT Bank 2

%

0%

Short Term FT Bank 2

Counts

128 Counts

Fuel Trim Cell Bank 1

Cell

Cell 17-19

Fuel Trim Cell Bank 2

Cell

Cell 17-19

KS Activity

Counts

Varies

Knock Sensor

Volts

4.76 Volts

Spark

Degrees

20°

Knock Retard

Degrees

CMP Retard

Degrees

-8°

Engine Run Time

Min/Sec

Varies

Scan Tool Data Display

Engine Data 2

Engine at Operating Temp/Engine Idling in Closed Loop/Closed Throttle/Park or Neutral/Accessories OFF

Scan Position

Units Displayed

Typical Data Value

Engine Speed

RPM

600-650 RPM

Desired Idle

RPM

600-650 RPM

EVAP Duty Cycle

%

13%-17%

EVAP Canister Purge

Off/On

On

Air Fuel Ratio

Ratio

14.7:1

EGR Duty Cycle

%

0%

Actual EGR Position

%

0%

Desired EGR Position

%

0%

EGR Sensor

Volts

0.64 Volts

Air Fuel Ratio

Ratio

14.7:1

Ignition 1

Volts

13.6 Volts

IAC Position

Counts

Varies

Desired IAC

Counts

Varies

ECT

Degrees

93°C (200°F)

Start Up ECT

Degrees

Varies

IAT

Degrees

Varies

CMP Retard

Degrees

-8°

Spark Control

Retard/Advance

Advance

Power Enrichment

Inactive/Active

Inactive

Brake Switch

Closed/Open

Closed

Clutch Pedal Switch

Released/Applied

Released

TR Switch

Park/Neutral

Park/Neutral

TFP Switch A/B/C

OFF ON OFF

OFF ON OFF

Vehicle Speed

km/h MPH

0 km/h 0 MPH

Decel Fuel Mode

Inactive/Active

Inactive

TP Sensor

Volts

.47-.53 Volts

TP Sensor

%

0%

MAP

kPa

30-35 kPa

MAP

Volts

1.07-1.31 Volts

BARO

kPa

95 kPa

BARO

Volts

4.58 Volts

1-2 Sol.

Off/On

On

2-3 Sol.

Off/On

On

3-2 Downshift Sol.

Off/On

On

TCC Enable

No/Yes

No

TCC Duty Cycle

%

0%

TCC Slip Speed

RPM

600 RPM

Cruise Mode

Off/On

Off

Engine Run Time

Min/Sec

Varies

Scan Tool Data Display

Engine Data 3

Engine at Operating Temp/Engine Idling in Closed Loop/Closed Throttle/Park or Neutral/Accessories OFF

Scan Position

Units Displayed

Typical Data Value

Engine Speed

RPM

600-650 RPM

Desired Idle

RPM

600-650 RPM

IAC Position

Counts

38 Counts

Desired IAC

Counts

38 Counts

INJ. PWM Average Bank 1

ms

3.0-3.6 ms

INJ PWM Average Bank 2

ms

3.0-3.6 ms

Engine Load

%

17%-19%

MAF Frequency

Hz

2190-2285 Hz

MAF

g/s

4.2-4.6 g/s

TP Sensor

Volts

0.47-0.51 Volts

TP Angle

%

0%

MAP

kPa

30-35 kPa

MAP

Volts

1.07-1.31 Volts

BARO

kPa

95 kPa

BARO

Volts

4.58 Volts

EVAP Duty Cycle

%

17%-19%

EGR Duty Cycle

%

0%

Actual EGR Position

%

0%

Desired EGR Position

%

0%

EGR Sensor

Volts

0.64 Volts

CMP Retard

Degrees

-8°

A/C Request

No/Yes

No

A/C Relay

Off/On

Off

Engine Run Time

Min/Sec

Varies

Scan Tool Data Display

HO2S Data

Engine at Operating Temp/Engine Idling in Closed Loop/Closed Throttle/Park or Neutral/Accessories OFF

Scan Position

Units Displayed

Typical Data Value

Engine Speed

RPM

600-650 RPM

Desired Idle

RPM

600-650 RPM

Pre HO2S

Not Ready/Ready

Ready

Post HO2S

Not Ready/Ready

Ready

HO2S Bank 1 Sensor 1

mV

Varies

HO2S Bank 1 Sensor 2

mV

Varies

HO2S Bank 2 Sensor 1

mV

Varies

HO2S Bank 1 Sensor 3

mV

Varies

Air Fuel Ratio

Ratio

14.7:1

HO2S XCounts Bank 1

Counts

Varies

HO2S XCounts Bank 2

Counts

Varies

Rich/Lean Bank 1

Rich/Lean

Varies

Rich/Lean Bank 2

Rich/Lean

Varies

Loop Status

Closed/Open

Closed

(CL) Since Restart

No/Yes

Yes

IAC Position

Counts

Varies

Desired IAC

Counts

Varies

MAF

g/s

4.2-4.6 g/s

Long Term FT Bank 1

%

0%

Long Term FT Bank 1

Counts

127 Counts

Long Term FT Bank 2

%

-3%

Long Term FT Bank 2

Counts

123 Counts

Short Term FT Bank 1

%

0%

Short Term FT Bank 1

Counts

128 Counts

Short Term FT Bank 2

%

0%

Short Term FT Bank 2

Counts

128 Counts

Long Term FT

Disenabled/Enabled

Enabled

Fuel Trim Cell Bank 1

Cell

Cell 17-19

Fuel Trim Cell Bank 2

Cell

Cell 17-19

ECT

Degrees

93°C (200°F)

Startup ECT

Degrees

Varies

Ignition 1

Volts

13.6 Volts

Engine Run Time

Min/Sec

Varies

Scan Tool Data Display

Misfire Data

Engine at Operating Temp/Engine Idling in Closed Loop/Closed Throttle/Park or Neutral/Accessories OFF

Scan Position

Units Displayed

Typical Data Value

Engine Speed

RPM

600-650 RPM

Desired Idle

RPM

600-650 RPM

Misfire Current Cyl. #1

Number of Misfires

0

Misfire Current Cyl. #2

Number of Misfires

0

Misfire Current Cyl. #3

Number of Misfires

0

Misfire Current Cyl. #4

Number of Misfires

0

Misfire Current Cyl. #5

Number of Misfires

0

Misfire Current Cyl. #6

Number of Misfires

0

Cycles of Misfire Data

Number of Cycles

Varies

Engine Speed

RPM

600-650 RPM

Desired Idle

RPM

600-650 RPM

Misfire History Cyl. #1

Number of Misfires

0

Misfire History Cyl. #2

Number of Misfires

0

Misfire History Cyl. #3

Number of Misfires

0

Misfire History Cyl. #4

Number of Misfires

0

Misfire History Cyl. #5

Number of Misfires

0

Misfire History Cyl. #6

Number of Misfires

0

Misfire Per Cycle Status

Counts

Varies

IAC Position

Counts

36 Counts

Desired IAC

Counts

36 Counts

Ignition 1 On

No/Yes

Yes

IAC Position

Counts

Varies

Desired IAC

Counts

Varies

Rich/Lean Bank 1

Rich/Lean

Varies

Rich/Lean Bank 2

Rich/Lean

Varies

A/C Relay

Off/On

Off

A/C Request

No/Yes

No

Brake Switch

Closed/Open

Closed

FT Enable

Off/On

On

Decel Fuel Mode

Inactive/Active

Inactive

Power Enrichment

Off/On

Off

TR Switch

Park/Neutral

Park/Neutral

TCC Forced Off

No/Yes

Yes

TCC Enable

No/Yes

No

Vehicle Speed

km/h MPH

0 km/h 0 MPH

Scan Tool Data Display

EVAP Data

Engine at Operating Temp/Engine Idling in Closed Loop/Closed Throttle/Park or Neutral/Accessories OFF

Scan Position

Units Displayed

Typical Data Value

MAP

kPa

30-35 kPa

MAP

Volts

1.07-1.31 Volts

TP Sensor

Volts

0.47-0.53 Volts

TP Angle

%

0%

Fuel Level

%

Varies

Fuel Level Sensor

Volts

Varies

Fuel Tank Pressure

in. H20

Varies

Weak Vacuum Test

Not Run/Fail

Not Run/Fail

Small Leak Test

Not Run/Fail

Not Run/Fail

Purge Leak Test

Not Run/Fail

Not Run/Fail

Excess Vacuum Test

Not Run/Fail

Not Run/Fail

EVAP Canister Purge

Off/On

On

EVAP Vent Solenoid

Closed/Open

Open

EVAP Duty Cycle

%

17%-19%

Engine Run Time

Min/Sec

Varies