Endurant HD
TRTS0950 EN-US
|
October 2024 - B

Fault Code 140: EBS Brake Switch

J1939: SA 3 SPN 1121 FMI 13, 19

Overview

The Transmission Control Module (TCM) receives the vehicle’s Electronic Braking System (EBS) Brake Switch message from a vehicle Electronic Control Unit (ECU) over the Primary Data Link (J1939A). This information is used to determine vehicle state.

Detection

The TCM monitors EBS Brake Switch messages. If messages are not received or are invalid, the fault is set Active.

Conditions to Set Fault Code Active

FMI 13 – Out of Calibration: EBS Brake Switch messages not available for 10 seconds.

FMI 19 – Received Network Data in Error: EBS Brake Switch messages invalid for 10 seconds.

Fallback

FMI 13, 19:

  • Amber warning lamp on
  • Urge to Move and Creep Mode prohibited
  • Hill Start Aid prohibited

Conditions to Set Fault Code Inactive

FMI 13, 19: EBS Brake Switch messages received and valid for 10 seconds.

Possible Causes

FMI 13, 19:

  • Vehicle Components - Vehicle ECU(s)
    • Vehicle EBS Brake Switch J1939 message not enabled
    • Other vehicle ECU(s) faulted
  • Vehicle Harness - Primary Data Link (J1939A)
    • Shorted to power, shorted to ground or open circuit
    • Terminals bent, spread, corroded, or loose

Note: Refer to OEM for troubleshooting a failed system.

Additional Tools

  • None

Fault Code 140 Troubleshooting

A
Purpose:Check for Active or Inactive fault codes.

  1. Set vehicle parking brake and chock wheels.

  2. Record the transmission fault codes, FMIs, occurrences, and timestamps from the Service Activity Report created during the Diagnostic Procedure.

  • If Fault Code 140 is Inactive and there are other Active vehicle or transmission fault codes, troubleshoot all Active fault codes. Go to Step V

  • If Fault Code 140 FMI 13 is Active, refer to OEM and enable vehicle EBS Brake Switch message (SPN 1121). Go to Step V

  • If Fault Code 140 FMI 13 is Inactive, Go to Step V.

  • If Fault Code 140 FMI 19 is Active or Inactive, Go to Step B

B
Purpose:Monitor vehicle EBS Brake Switch signal message.

  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. Select “Status”.

  8. Select “EBS brake switch”.

  9. Select all of the “- 1121” SPN sources.

    Note: Not all sources will indicate a value.

  10. Monitor 1121 - EBS brake switch value. Record reading in table.

  11. Depress and hold service brake.

  12. Release vehicle parking brake.

  13. Monitor 1121 - EBS brake switch value. Record reading in table.

  14. Set vehicle parking brake.

  15. Compare reading(s) in table.

  • If readings are out of range, refer to OEM guidelines for repair of the vehicle EBS Brake Switch signal message (SPN 1121). Go to Step V

  • If readings are in range, no fault was found. The intermittent nature of the fault makes it likely that the problem is in the vehicle EBS Brake Switch signal message (SPN 1121). Contact OEM for further diagnostic instructions. Go to Step V

EBS Brake StateParameterRangeReading(s)
Set1121-EBS brake switchSet
Released1121-EBS brake switchNot set
V
Purpose:Verify repair.

  1. Key off.

  2. Reconnect all connectors and verify that all components are properly installed.

  3. Key on with engine off.

  4. Connect ServiceRanger.

  5. Go to “Fault Codes”.

  6. Select “Clear All Faults”.

  7. Operate vehicle and attempt to reset the fault code or duplicate the previous complaint.

  8. Check for fault codes using ServiceRanger.