GM Service Manual Online
For 1990-2009 cars only

TBCM Scan Tool Data List

Scan Tool Parameter

Data List

Units Displayed

Typical Data Value

Operating Conditions: Ignition is ON, engine OFF, and vehicle is stationary

ABS Active

TBCM

Yes/No

No

Brake Apply Pressure Status

TBCM

Invalid/Valid

Valid

Battery Voltage Signal

TBCM

Volts

B+

Brake Switch Status

TBCM

On/Off

Off

Electric Trailer Brakes Detected

TBCM

Yes/No

No

TBCM Diagnostic Fault

TBCM

Yes/No

No

Ignition Run/Crank

TBCM

Active/Inactive

Inactive

Low Speed Brake Hold

TBCM

Active/Inactive

Inactive

Master Cylinder Pressure Sensor Input

TBCM

kPa/psi

Varies

Manual Apply Switch

TBCM

%

Varies

Manual Apply Switch Position Error

TBCM

%

Varies

Redundant Manual Apply SW.

TBCM

%

Varies

Trailer Brake Control

TBCM

Disabled/Enabled

Enabled

TBCM Relay Feedback Signal

TBCM

Volts

12 Volts

Trailer Stop Lamp Signal

TBCM

Not Requested/Requested

Not Requested

Trailer Brake Relay Cmd.

TBCM

Volts

12 Volts

TBCM Duty Cycle

TBCM

%

Varies

Trailer Brake Relay Cmd.

TBCM

Volts

12 Volts

Trailer Brake Relay Status

TBCM

Disabled/Enabled

Enabled

Trailer Connection Detected

TBCM

Yes/No

No

Trailer Disconnect Detected

TBCM

Yes/No

No

User Gain Switch

TBCM

%

Varies

Vehicle Speed

TBCM

km/h or mph

km/h or mph