The trailer brake control (TBCM) scan tool data definitions contain a brief description of all TBCM related parameters available on the scan tool. The parameters available on the scan tool are listed below in alphanumeric order.

ABS Active: The scan tool displays Yes/No. The scan tool displays No when ABS is not active.

Brake Apply Pressure Status: The scan tool displays Invalid or Valid. The scan tool displays Valid when the ignition is ON, and the brake apply sensor is not faulted.

Battery Voltage Signal: The scan tool displays 0-18 Volts. The scan tool displays approximately 12 Volts when the ignition is ON.

Brake Switch Status: The scan tool displays On/Off. The scan tool indicates Off when the brake is not applied.

Electric Trailer Brakes Detected: The scan tool displays Yes or No. The scan tool displays Yes when the vehicle is connected to a trailer equipped with electric brakes.

TBCM Diagnostic Fault: The scan tool will display Yes or No if a fault is detected. The scan tool will display the Yes if a fault signal is received from the TBCM.

Ignition Run/Crank: The scan tool will display Active or Inactive. The scan tool will display Active when the signal received from the ECM Run/Crank position.

Low Speed Brake Hold: The scan tool displays Active or Inactive. The scan tool displays Inactive when the vehicle is not moving or is moving at speeds less than or equal to 0 km/h (0 mph).

Master Cylinder Pressure Sensor Input: The scan tool will display brake fluid pressure. The scan tool will display kPa or psi signal received from the TBCM.

Manual Apply Switch: The scan tool displays percent of manual apply lever travel. The scan tool displays 0-100%.

Manual Apply Switch Position Error: The scan tool displays percent of error between the manual apply and redundant manual apply signals. The scan tool displays 0-100%. A proper functioning switch should have a value less than 20 %

Redundant Manual Apply SW. : The scan tool displays percent of manual apply lever travel using a redundant signal track. The scan tool displays 0-100%

Trailer Brake Control: The scan tool will display Engage/Disengage. The scan tool will display the signal received from the TBCM.

Trailer Stop Lamp Signal: The scan tool will display Not Requested or Requested depending on the state of the brake switch, and manual apply lever. Requested will be displayed if the brake switch is active or the manual apply lever is applied.

Trailer Brake Relay Cmd. : The scan tool will display voltage depending on the state of the battery, and should have a reading between 6 and 10 volts when the solid state relay is enabled and no output duty cycle is commanded.

TBCM Duty Cycle:  The scan tool displays percent of battery voltage output commanded to the trailer brakes and depends on battery voltage and user gain setting. Approximately 100% will be indicated when user gain is set to 10.0 and the manual apply lever is fully applied with the engine running.

TBCM Relay Feedback Signal: The scan tool displays percent of PWM. The scan tool displays 0-100%.

Trailer Brake Relay Cmd. : The scan tool displays 0-18 Volts. The scan tool displays voltage commanded to the trailer brakes when a trailer with electric brakes is connected and depends on battery voltage and user gain setting. Approximately 12-14 volts will be indicated when user gain is set to 10.0 and the manual apply lever is fully applied with the engine running.

Trailer Brake Relay Status: The scan tool will display Disabled or Enabled. Enabled will be displayed whenever there are no faults present in the TBCM system.

Trailer Connection Detected: The scan tool displays Yes or No. The scan tool displays Yes when a trailer with electric trailer brakes is connected.

Trailer Disconnect Detected: The scan tool will display Yes or No depending on the trailer connections. Yes will be displayed if a trailer connection is made to a trailer equipped with electric trailer brakes, and a disconnect occurs within the same ignition cycle.

User Gain Switch: The scan tool displays percent of full gain setting. The scan tool displays 0-100%. Each full gain setting represents an increment of approximately 10 percent of full gain setting. Approximately 40% will be indicated with a gain setting of 4.0, 65% will be indicated with a gain setting of 6.5, etc.

Vehicle Speed: The scan tool displays 0-327 km/h (0-204 mph). The scan tool displays 0 km/h (0 mph) when the vehicle is not moving or is moving at speeds less than or equal to 0 km/h (0 mph).