GM Service Manual Online
For 1990-2009 cars only

If you have completed the On-Board Diagnostic (OBD) system check, if the diagnostics are functioning properly, and if no DTCs are displayed, you may use the Typical Scan Tool Data Values in the table below for comparison. These values are an average of display values recorded from normally operating vehicles.

Important: You should never use a scan tool that displays faulty data. The problem should be reported to the manufacturer. The use of a faulty scan tool can result in misdiagnosis and the unnecessary replacement of parts.

Only the parameters listed below are used in this manual for diagnosing. If a scan tool displays other parameters, the values are not recommended by General Motors for use in diagnosis.

The values below were recorded under the following conditions:

    • Engine is at Idle
    • Upper radiator hose is hot
    • Closed throttle
    • Gear is in Park or Neutral
    • Closed Loop
    • Accessories are OFF

Typical Scan Tool Data Values

Tech 2 Parameter

Units Displayed

Typical Scan Values

Engine Torque

N·m (lb ft)

varies

TP Sensor

volts

0.3-0.9 V

TP Angle

percent

0%

Engine Speed

RPM

varies

Transmission OSS

RPM

0

Vehicle Speed

mph (km/h)

0

Current Gear

1,2,3,4

1

1-2 Sol.

On/Off

On

2-3 Sol.

On/Off

On

3-2 Downshift Sol.

On/Off

On

Speed Ratio

Ratio

8.00:1

1-2 Sol. Open

Yes/No

No

1-2 Sol. Shorted

Yes/No

No

2-3 Sol. Open

Yes/No

No

2-3 Sol. Shorted

Yes/No

No

3-2 Downshift Sol. Open

Yes/No

No

3-2 Downshift Sol. Shorted

Yes/No

No

TFP Switch A/B/C

On/Off

Off/On/Off

Trans. Fluid Temp.

°C (°F)

varies

TFT Sensor

volts

varies

ECT

°C (°F)

varies

Transmission Hot Mode

On/Off

Off

PC Sol. Actual Current

amps

varies (0.1-1.1 amps)

PC Sol. Ref. Current

amps

varies (0.1-1.1 amps)

PC Sol. Duty Cycle

percent

varies

TCC Brake Switch

Closed/Open

Closed

TCC Enable

Yes/No

No

TCC Duty Cycle

percent

0%

TCC Slip Speed

RPM

+/- 50 RPM from the Engine Speed

TCC Enable Open

Yes/No

No

TCC Enable Shorted

Yes/No

No

TCC Duty Cycle Open

Yes/No

No

TCC Duty Cycle Shorted

Yes/No

No

1-2 Shift Time

seconds

varies

2-3 Shift Time

seconds

varies

3-4 Shift Time

seconds

varies

Adaptable Shift

Yes/No

No

Engine Run Time

hr/min/sec

varies

Ignition Voltage

Volts

varies

Cruise

Enabled/Disabled

Disabled

A/C Clutch

On/Off

Off

Power Take Off

Yes/No

No

1-2 Shift Error

seconds

varies

2-3 Shift Error

seconds

varies

3-4 Shift Error

seconds

varies

Current TAP

0-16

varies

Maximum TAP

Yes/No

No

Last TAP

psi

varies

TAP% of TP

psi

varies