The Transmission Electronic Control Unit (TECU) uses a Grade Sensor to calculate vehicle incline or grade. The grade position is used for the Hill Start Aid (HSA) feature and provides information to assist in vehicle launch and shifting. The Grade Sensor is internal to the TECU. Fault Code 68 FMI 13 indicates a Grade Sensor Calibration is required.

The Grade Sensor is calibrated via ServiceRanger or an Operator-Triggered Procedure.

Note: Verify the following prior to performing the Grade Sensor Calibration with ServiceRanger or the Operator Triggered Procedure:

• Vehicle must be on level ground before initiating the grade sensor calibration.
• Verify the suspension is fully aired.
• Verify the suspension is set to proper height.
• Ground surface must be within +/- 0.5% grade (0.28 degrees) from level.
• Maximum allowable grade is +/- 0.5 degrees (0.87% grade) from level.

ServiceRanger Procedure

• Set vehicle parking brake and chock wheels.

  Note: Verify vehicle is parked on level ground and the suspension is fully aired (if equipped) and set to proper ride height.

• Key on with engine off.
• Connect ServiceRanger.
• Go To “Service Routines.”
• Select "Start" Grade Sensor Calibration.
• Follow on-screen prompts.

Operator-Triggered Procedure

• Set vehicle parking brake and chock wheels.

  Note: Verify vehicle is parked on level ground and the suspension is fully aired (if equipped) and set to proper ride height.

• Key on with engine off.
• Select Low mode with the Transmission Driver Interface Device.
• Select Upshift Requests until the Display indicates "6".
• Depress and hold the Accelerator Pedal to the floor.
• When the Display indicates a "Down Arrow", release the Accelerator Pedal.
• When the Display indicates "0", select Neutral mode.
• Key off and allow the TECU to perform a complete power down sequence.