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

Tech 2 Data Value Examples

Tech 2 Parameter

Units Displayed

Typical Scan Values

Engine Torque

lb ft/N·m

varies

TP Indicated Angle

percent

0%

TP Desired Angle

percent

0%

APP Indicated Angle

percent

0%

APP Average

counts

varies

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/Short to GND

Yes/No

No

1-2 Sol. Short to Volts

Yes/No

No

2-3 Sol. Open/Short to GND

Yes/No

No

2-3 Sol. Short to Volts

Yes/No

No

3-2 Sol. Open/Short to GND

Yes/No

No

3-2 Sol. Short to Volts

Yes/No

No

TFP Sw. A/B/C

On/Off

Off/On/Off

ECT

°C(°F)

varies

IAT

°C(°F)

varies

Trans. Fluid Temp.

°C(°F)

varies

TFT Sensor

volts

varies

Hot Mode

On/Off

Off

PC Sol. Actual Current

amps

varies (0.1-1.1 amps)

PC Solenoid Ref. Current

amps

varies (0.1-1.1 amps)

PC Sol. Duty Cycle

percentage

varies

TCC Brake Switch

Open/Closed

Closed

TCC Enable

Yes/No

No

TCC Mode

0-5

0

TCC Duty Cycle

Percentage

0%

TCC Slip Speed

RPM

+/- 50 RPM from the Engine Speed

TCC Enable Open/Short to GND

Yes/No

No

TCC Enable Short to Volts

Yes/No

No

TCC Duty Cycle Open/Short to GND

Yes/No

No

TCC Duty Cycle Short to Volts

Yes/No

No

Latest Shift

seconds

varies

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

1-2 Shift Error

seconds

0.00

2-3 Shift Error

seconds

0.00

Current TAP Cell

0-16

varies

Current TAP Memory

-16 to +16

varies

1-2 TAP % of TP

psi

varies

2-3 TAP % of TP

psi

varies