GM Service Manual Online
For 1990-2009 cars only

Scan Tool Parameter

Units Displayed

Cold Key On¹

Cold Idle¹

Hot Idle¹

55 MPH Cruise²

5 Volt Ref. Low

Volts

0.0 - 0.2

0.0 - 0.2

0.0 - 0.2

0.0 - 0.2

5 Volt Ref. High

Volts

4.8 - 5.2

4.8 - 5.2

4.8 - 5.2

4.8 - 5.2

Actual Gas Flow

gms/sec

0.0

0.4 - 0.7

0.4 - 0.7

varies

Alternative Fuel Level

%

Near gauge reading

Near gauge reading

Near gauge reading

Near gauge reading

Alternative Fuel Mileage Log

miles/ km

varies

varies

varies

varies

Alternative Fuel Run Time Log

Hours

varies

varies

varies

varies

BARO

kPa/ V

85 to 103 kPa

85 to 103 kPa

85 to 103 kPa

85 to 103 kPa

Battery Voltage

Volts

within 1.5 volts of battery volts

within 1.5 volts of battery volts

within 1.5 volts of battery volts

within 1.5 volts of battery volts

Desired Gas Flow

gms/sec

0.0

0.4 - 0.7

0.4 - 0.7

varies

ECT

°C (°F)/Volts

-20°C to 50°C

-20°C to 50°C

90°C to 110°C

90°C to 110°C

EGR Sensor

Volts

0.65 to 0.80

0.65 to 0.80

0.65 to 0.80

2.50

Engine Load

%

0%

1 to 5

1 to 5

13

Engine Run Time

Hr. / Min. / Sec.

0:00:00

Varies

Varies

Varies

Engine Speed

RPM

0

Within 80 RPM of Desired Idle

Within 80 RPM of Desired Idle

1700

Fuel Gauge Relay

Gasoline/ Alt. Fuel

AF

AF

AF

AF

Fuel Gauge Select Sw.

Released/ Depressed

Released

Released

Released

Released

Fuel Indicator Lamp

On/ Off

On two seconds then Off

Off

Off

Off

Fuel Pressure Sensor

psi/ V

350 to 3600 psi

350 to 3600 psi

350 to 3600 psi

350 to 3600 psi

Fuel Pump Relay (Alt. Fuel)

On/Off

Off 2 seconds then On

On

On

On

Fuel Temperature Sensor

°C(°F)/ V

near IAT

cooler than IAT

cooler than IAT

cooler than IAT

Gasoline Fuel Mileage Log

miles/ km

Varies

Varies

Varies

Varies

Gasoline Fuel Run Time Log

Hours

Varies

Varies

Varies

Varies

High Pressure Lockoff

Open/ Closed

Open 1 second then closed

Open

Open

Open

HO2S Bank 1 Sensor 1

Volts

351 to 551 mV

Varies

Varying

Varying

HO2S Bank 2 Sensor 1

Volts

351 to 551 mV

Varies

Varying

Varying

IAT

°C (°F)/V

near outside temp

near outside temp

underhood temp

underhood temp

Loop Status

Open/ Closed

Open

Varies

Closed

Closed

Long Term FT Avg.

%

0%

-25% to 25%

-25% to 25%

-25% to 25%

Low Pressure Lockoff

Open/ Closed

Closed

Open

Open

Open

MAF

gms/sec

2.4

9.8 to 11.0

5.0 to 7.0

20 to 28

MAP

kPa/ V

equal to barometric pressure

30 to 50 kPa

1.50V @ 38 kPa

30 to 50 kPa

1.50V @ 38 kPa

65 / 2.88

MIL Input (Gasoline)

Yes/ No

Yes

No

No

No

MIL Output (Alt. Fuel)

On/ Off

On

Off

Off

Off

Mixture Control Valve

Hz

0

Varies

Varies

Varies

NGO Enable Input

(from VCM)

Gasoline/ ALT Fuel

Varies

AF

AF

AF

NGO Enable Output

Gasoline/ ALT Fuel

Varies

AF

AF

AF

Short Term FT Avg.

%

0%

-5% to 5%

-8% to 8%

-10% to 10%

TP Angle

%

0%

0%

0%

11%

TP Sensor

Volts

0.55

0.55

0.55

1.05

Vehicle Speed

km/H (mph)

0

0

0

55 MPH

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 ACCs 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.