Endurant HD
TRTS0950 EN-US
|
September 2024 - B

Brake Switch Functionality Test

Overview

This procedure does not relate to any specific fault code, but verifies that the Transmission Control Module (TCM) is receiving service brake switch input and park brake switch input from the vehicle.

Detection

  • Transmission does not engage a gear from Neutral.

    Note: The transmission will not engage a gear from Neutral if the service brake is not depressed.

Possible Causes

  • Vehicle Service Brake Switch Input Messages
    • Not available, not sent or in error
  • Service Brake Switch
    • Internal failure
  • Park Brake Switch
    • Internal failure

Brake Switch Functionality Test

A
Purpose:Monitor Service Brake Switch signal in ServiceRanger.

  1. Set vehicle parking brake and chock wheels.

  2. Key on with engine running.

  3. Allow air pressure to build to governor cut off.

  4. Key off.

  5. Key on with engine off.

  6. Connect ServiceRanger.

  7. Go To “Data Monitor”.

  8. From the Default Parameter Files select “Vehicle Brake Messages”.

    Note: Not all sources will indicate a value.

  9. Monitor two Vehicle Brake parameters. Record parameters and their values in table.

  10. Depress and hold service brake.

  11. Monitor the same two Vehicle Brake parameters and record their values in table.

  12. Release service brake.

  13. Compare reading(s) in table.

  • If two parameters with values are not indicated or values did not change with the service brake depressed, refer to OEM guidelines for repair or replacement of the service brake switch/signal. Go to Step V.

    Note: The transmission requires a minimum of two valid service brake switch input messages from the vehicle to engage a gear from Neutral.

  • If two or more parameters are indicated and their values changed with the service brake depressed, no fault was found. Go to Step B

Service Brake StateService Brake Parameters IndicatedValue(s)
Released1.
2.
Depressed1.
2.
B
Purpose:Verify Vehicle Parking Brake Switch signal with ServiceRanger.

  1. Key on with engine running.

  2. Allow air pressure to build to governor cut off.

  3. Key off.

  4. Key on with engine off.

  5. Connect ServiceRanger.

  6. Go To “Data Monitor”.

  7. From the “Default Parameter Files” tab, select “Vehicle Brake Messages”.

  8. Monitor 70 - Parking brake switch status. Record reading in table.

  9. Depress and hold service brake.

  10. Release vehicle parking brake.

  11. Monitor 70 - Parking brake switch status value. Record reading in table.

  12. Set vehicle parking brake.

  13. Monitor 70 - Parking brake switch status. Record reading in table.

  14. Compare reading(s) in table.

  • If readings are out of range, refer to OEM guidelines for repair or replacement of the Parking Brake Switch/signal.

  • If readings are in range, Contact Eaton Cummins Automated Transmission Technologies for further diagnostic instructions. For Help Line phone numbers, go to Contact Information.

Parking Brake StateParameterRangeReading(s)
Set70-Parking brake switch statusSet
Not set70-Parking brake switch statusNot set
Set70-Parking brake switch statusSet