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 - Engine Controls 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 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 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.

Eng 1: Engine 1 Data List

Eng 2: Engine 2 Data List

FS: Fuel System Data List

EGR: Exhaust Gas Recirculation (EGR) Data List

TC: TC Data List

FF/FR: Freeze Frame/Failure Records Data List

Scan Tool Data List

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Operating Conditions: Engine Idling/Lower Radiator Hose Hot/Closed Throttle/Park or Neutral/Accessories Off

4WD Low Signal

Eng 1

Enabled/Disabled

Disabled

4WD Signal

Eng 1

Enabled/Disabled

Disabled

5 volts Reference 1

FS

Volts

Varies

5 volts Reference 2

FS

Volts

Varies

5 volts Reference 3

FS

Volts

Varies

A/C Clutch Feedback Signal

Eng 1

Relay ON/OFF

Relay OFF

A/C High Side Pressure

Eng 1

Volts

Varies

A/C Relay Command

Eng 1, EGR, TC

ON/OFF

Off

A/C Request Signal

Eng 1

Yes/No

No

A/C Sec. High Press. SW

Eng 1

Open/Closed

Closed

Actual Fuel Rail Pressure

All

MPa/PSI

37-40 MPa (5,200-5,800 PSI)

APP Indicated Angle

All

%

0.0

APP Sensor 1

Eng 1, FF/FR

Volts

  • 0.44-0.95 (Idle)
  • 0.75-1.25 (2,500 RPM)

APP Sensor 2

Eng 1, FF/FR

Volts

  • 3.9-4.5 (Idle)
  • 3.7-4.3 (2,500 RPM)

APP Sensor 3

Eng 1, FF/FR

Volts

  • 3.6-4.1 (Idle)
  • 3.5-4.0 (2,500 RPM)

Balancing Rate Cyl. 1-8

Eng 2, FF/FR

mm³

-4.0 to +4.0

BARO

Eng 1, EGR, TC, FF/FR

kPa

65-104 (Varies with altitude)

Battery Voltage

Eng 1

Volts

12-14 (Accuracy +/- 0.4 Volts)

Boost Pressure Sensor

Eng 1, EGR, TC, FF/FR

kPa/PSI

60-170 kPa (8-24 PSI) (All RPM)

Boost Pressure Sensor

TC

volts

Varies

Calculated Fuel Rate

All

mm³

7-9

CAM Reference Signal Missed

Eng 1

Counts

0

CAM Signal Present

Eng 1

Yes/No

Yes

Check Trans Lamp

Eng 1

ON/OFF

OFF

CKP Sensor Pulses Missed

Eng 1

Counts

0

Clutch Pedal Switch

Eng 1

Applied/Released

Released

Cruise Control Active

Eng 1

Yes/No

No

Cruise ON/OFF Switch

Eng 1

ON/OFF

OFF

Cruise/Resume/Accel Switch

Eng 1

ON/OFF

OFF

Cruise Set/Coast Switch

Eng 1

ON/OFF

OFF

Crank Signal Present

Eng 1

Yes/No

Yes

Desired EGR Position

EGR

%

Varies

Desired FRP Regulator

FS

mA

1,200-1,400

Desired Fuel Rail Pressure

All

MPa/PSI

37-40 MPa (5,200-5,800 PSI)

Desired Idle Speed

Eng 1, FF/FR

RPM

630-700

Desired TC Vane Position

TC

%

20%

Desired TC Vane Pos. Ctrl. Solenoid

TC

Amps

0.1

DTC Set This Ignition

Eng 1

Yes/No

No

ECT Sensor

Eng 1, FS, EGR, TC, FF/FR

°C/°F

85°C-105°C /185°F-220°F (Varies with temperature)

EGR Learned Minimum Position

EGR

%

Varies

EGR Position Sensor

EGR

Volts

Varies

EGR Position Sensor

EGR

%

Varies

EGR Position Variance

EGR

%

Varies

EGR Solenoid Command

EGR

%

Varies

Engine Oil Level Switch

Eng 1

OK/Fault

OK

Engine Oil Life Remaining

Eng 1

%

Varies

Engine Oil Pressure Sensor

FS

kPa/PSI

Varies

Engine Run Time

All

Hrs/Mins/Sec

Varies with engine run time

Engine Speed

All

RPM

+/-100 RPM from desired

Fail Counter

FR

counts

Varies

FRP Regulator Command

Eng 1, Eng 2, FS, TC, FF/FR

%

40-50

FRP Regulator Command

FS, FF/FR

mA

Varies

FRP Regulator Relay

Eng 1

ON/OFF

ON

FRP Regulator Fuel Flow Command

FS

mm³

Varies

Front Axle Switch

Eng 1

Lock/Unlock

Unlock

Fuel Level Sensor

FS

%

Varies

Fuel Level Sensor

FS

Volts

Varies with fuel level

Fuel Level Sensor Rear

FS

Volts

Varies

Fuel Temperature Sensor

Eng 1, Eng 2, FS, FF/FR

°C/°F

10-90°C/50-194°F

Glow Plug Relay

Eng 1

ON/OFF

OFF

GEN L Terminal Signal

Eng 1

Voltage/No Voltage

No Voltage

High Idle Swtch-if equipped

Eng 1

ON/OFF

OFF

IAT Sensor

Eng 1, EGR, TC, FF/FR

°C/°F

10-90°C/50-194°F (temperatures may increase under heavy engine loads)

Ignition 1 Signal

Eng 1, EGR, TC, FF/FR

Volts

12-14 (accuracy +/-0.4 volts)

Ignition Off Time

EGR, TC

minutes

Varies

Injector 1-8 Command

Eng 2, FF/FR

ms

0.3-0.5

Low Coolant Level

Eng 1

Yes/No

No

MAF

Eng 1

Volts

Varies

MAF Sensor

Eng 1, FS, EGR, TC, FF/FR

g/s

45-50

Main Injection Command

FS

microseconds

Varies

Main Injection Fuel Rate

FS

mm³

6.5-8.5

Main Injection Timing

Eng 1, Eng 2, FS, FF/FR

degrees

Varies

MIL Command

Eng 1

ON/OFF

OFF

Mileage Since First Failure

FF/FR

Miles/Km

Varies

Mileage Since Last Failure

FF/FR

Miles/Km

Varies

Not Run Counter

FR

counts

Varies

Pass Counter

FR

counts

Varies

PCM in VTD Fail Enable

Eng 1

Yes/No

No

PCM Reset

Eng 1, EGR, TC

Yes/No

No

Pilot Injection Command

FS

microseconds

Varies

Pilot Injection Fuel Rate

FS

mm³

0.8-1.0

Pilot Injection Timing

FS

degrees

Varies

PNP Switch

Eng 1, EGR

In Gear/Park/Neutral

Park/Neutral

PTO Enable

Eng 1

YES/NO

NO

PTO Engage Relay Command

Eng 1

ON/OFF

OFF

PTO Engine Shutdown Signal

Eng 1

YES/NO

NO

PTO Feedback Signal

Eng 1

Relay ON/Relay OFF

Relay OFF

Reverse Enable

Eng 1

Yes/No

No

Start up ECT

Eng 1, FF/FR

°C/°F

Varies (ECT at time of engine startup)

Start up IAT

Eng 1

°C/°F

Varies (IAT at time of engine startup)

Stoplamp Pedal Switch

Eng 1

Applied/Released

Released

TC Vane Learned Closed Position

TC

counts

Varies

TC Vane Learned Open Position

TC

counts

Varies

TC Vane Position Learned

TC

Yes/No

Yes

TC Vane Position Sensor

TC

Amps

0.1

TC Vane Pos. Ctrl. Solenoid

TC

%

70

TCC/Cruise Brake Pedal Switch

Eng 1

Applied/Released

Released

Vehicle Speed Sensor

Eng 1, FS, EGR, TC, FF/FR

mph/km/h

0

VTD Auto Learn Timer

Eng 1

Active/Inactive

Inactive

VTD Fuel Disable

Eng 1

Active/Inactive

Inactive

VTD Fuel Disable Until Ign. Off

Eng 1

Yes/No

No

Wait To Start

Eng 1

ON/OFF

OFF

Water In Fuel

Eng 1

ON/OFF

OFF