UltraShift PLUS
TRTS0940 EN-US
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July 2024 - A

Fault Code 23: Urge to Move Brake Switch Signal

J1939 SA 3 SPN 116 FMI 9, 13

SPN 521 FMI 9, 13

SPN 597 FMI 9, 13

SPN 1121 FMI 9, 13

SPN 8484 FMI 9, 13

SPN 520215 FMI 14

SPN 520216 FMI 31

Overview

The UltraShift PLUS transmission may be configured with the Urge to Move (UTM) feature. If enabled and the transmission is in gear, UTM allows the vehicle to start moving after the vehicle service brake is released without having to depress the accelerator pedal. The UTM feature requires a primary on/off brake switch signal and one of two secondary brake signal messages to function. The brake signal messages are broadcast via J1939 to the Transmission Electronic Control Unit (TECU).

Detection

The TECU communicates with the vehicle over the J1939 Data Link. If the vehicle secondary brake signal messages are not received, the fault sets active.

Conditions to Set Fault Code Active

FMI 9 – Abnormal Update Rate: Brake Input Signal message not received for 5 seconds.

FMI 13 – Out of Calibration: Brake Input Signal message received in error or is out of range.

FMI 14 – Special Instructions: UTM is enabled and the TECU has never received the Brake Pedal Position or Brake Application Pressure signal messages in 5 seconds.

FMI 31 – Condition Exists: Primary Brake Input Signal and Secondary Brake Input Signal are configured to the same value.

Fallback

All FMIs:

  • Urge to Move is inoperative.

Conditions to Set Fault Code Inactive

All FMIs:

  • Key off, TECU powered down, key on and one of the two secondary brake signal messages are available.

Possible Causes

FMI 9, 13:

  • Brake or Vehicle Controller (OEM determined)
    • Component and/or system fault
  • J1939 Data Link
    • J1939 Data Link damage between TECU and Brake or Vehicle Controller
    • Bent, spread, corroded or loose terminals
    • Wiring shorted to ground, shorted to power or open

FMI 14:

  • Brake Input Signal message never received.

FMI 31:

  • TECU
    • Configuration

Fault Code 23 Troubleshooting

A
Purpose:Check for Active or Inactive fault codes.

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

  • If Fault Code 22, 35 or 36 is Active, troubleshoot per Fault Code Isolation Procedure Index.

  • If Fault Code 23, SPN 521, FMI 9 or 13 is Active, Go to Step B

  • If Fault Code 23, SPN 520216, FMI 31 is Active, Go to Step C

  • If Fault Code 23, SPN 520216, FMI 31 is Inactive, Brake Input Signals are configured correctly, Go to Step V

  • If Fault Code 23, SPN 520215, FMI 14 is Active or Inactive, Go to Step D

  • If Fault Code 23, SPN 597, FMI 9 or 13 is Active or Inactive,Go to Step E

  • If Fault Code 23, SPN 116, FMI 9 or 13 is Active or Inactive, Go to Step F

  • If Fault Code 23, SPN 1121, FMI 9 or 13 is Active or Inactive, Go to Step G

  • If Fault Code 23, SPN 8484, FMI 9 or 13 is Active or Inactive, Go to Step H

B
Purpose:Monitor Brake Pedal Position.

  1. Key off.

  2. Set vehicle parking brake and chock wheels.

  3. Key on with engine running.

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

  5. Key off.

  6. Key on, engine off.

  7. Connect ServiceRanger.

  8. Select “Data Monitor”.

  9. Select “Position”.

  10. Select “Brake pedal position”.

  11. Select all of the SPN 521 sources.

  12. Service brake released, monitor ServiceRanger and record “Brake pedal position” value in table.

  13. Depress and hold service brake, monitor ServiceRanger, and record “Brake pedal position” value (reading) in table.

    Notice
    The “Brake pedal position” value may not be indicated in all the sources selected. Only one valid “Brake pedal position” value is required to support UTM.

  14. Compare reading(s) in table.

  • If reading(s) are in range, no problem was found. The intermittent nature of the fault makes it likely that the problem is in the Brake Pedal Position signal. Contact the OEM for further help troubleshooting the issue.

  • If reading(s) is out of range, refer to OEM guidelines for repair or replacement of the Brake Pedal Position signal. Go to Step V

Service Brake StateRangeReading(s)
Released0%
Depressed1% - 100%
C
Purpose:Compare Primary and Secondary Brake Input Signal Values.

  1. Key on, engine off.

  2. Connect ServiceRanger.

  3. Go To “Configuration”.

  4. Select “Vehicle”.

  5. Locate “Primary Brake Input Signal” and record value in table.

  6. Locate “Secondary Brake Input Signal” and record value in table.

  7. Compare reading(s) in table.

  • If Primary and Secondary Brake Input Signals are configured to the same value:

    • From the Primary Brake Input Signal New Value drop down select “Default”.
    • From the Secondary Brake Input Signal New Value drop down select “Default”.
    • Select “Apply” and follow the on-screen prompts. Go to Step V

  • If Primary and Secondary Brake Input Signals are not configured to the same value, contact Eaton at 1-800-826-HELP (4357) for further diagnostic instructions. Go to Step V

Brake Input SignalReading(s)
Primary Brake Input Signal
Secondary Brake Input Signal
D
Purpose:Contact OEM regarding brake signal messages availability.

  1. Contact OEM regarding availability of “Brake Pedal Position” – SPN 521, “Brake Switch” – SPN 597 or “Brake Application Pressure” – SPN 116 signals on the vehicle.

    Notice
    If UTM was just enabled the vehicle may not be equipped with the required secondary brake signal messages to support the feature.

  • If one or both brake signals are available, configure vehicle per OEM guidelines and perform a TECU power down. Go to Step V

  • If both secondary brake signal messages are not available, the vehicle does not support UTM. Disable UTM, Go to Step V

E
Purpose:Monitor Brake Switch Status.

  1. Key off.

  2. Set vehicle parking brake and chock wheels.

  3. Key on with engine running.

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

  5. Key off.

  6. Key on, engine off.

  7. Connect ServiceRanger.

  8. Select “Data Monitor”.

  9. Select “Status”.

  10. Select “Brake switch”.

  11. Select all of the SPN 597 sources.

  12. Service brake released, monitor ServiceRanger and record “Brake switch” value (reading) in table.

  13. Depress and hold service brake, monitor ServiceRanger, and record “Brake switch” value (reading) in table.

    Notice
    The “Brake switch” value may not be indicated in all the sources selected. Only one valid “Brake switch” value is required to support UTM.

  14. Compare reading(s) in table.

  • If reading(s) are in range, no problem was found. The intermittent nature of the fault makes it likely that the problem is in the Brake switch signal. Contact the OEM for further help troubleshooting the issue.

  • If reading(s) is out of range, refer to OEM guidelines for repair or replacement of the Brake switch signal. Go to Step V

Service Brake StateRangeReading(s)
ReleasedReleased
DepressedDepressed
F
Purpose:Monitor Brake Application Pressure.

  1. Key off.

  2. Set vehicle parking brake and chock wheels.

  3. Key on with engine running.

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

  5. Key off.

  6. Key on, engine off.

  7. Connect ServiceRanger.

  8. Select “Data Monitor”.

  9. Select “Pressure”.

  10. Select “Brake application pressure”.

  11. Select all of the SPN 116 sources.

  12. Service brake released, monitor ServiceRanger and record “Brake application pressure” value (reading) in table.

  13. Depress and hold service brake, monitor ServiceRanger, and record “Brake application pressure” value (reading) in table.

    Notice
    The “Brake application pressure” value may not be indicated in all the sources selected. Only one valid “Brake application pressure” value is required to support UTM.

  14. Compare reading(s) in table.

  • If reading(s) are in range, no problem was found. The intermittent nature of the fault makes it likely that the problem is in the Brake Application Pressure signal. Contact the OEM for further help troubleshooting the issue.

  • If reading(s) is out of range, refer to OEM guidelines for repair or replacement of the Brake Application Pressure signal. Go to Step V

Service Brake StateRangeReading(s)
Released0 PSI
Depressed1 PSI - 145 PSI
G
Purpose:Monitor EBS Brake Switch Status.

  1. Key off.

  2. Set vehicle parking brake and chock wheels.

  3. Key on with engine running.

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

  5. Key off.

  6. Key on, engine off.

  7. Connect ServiceRanger.

  8. Select “Data Monitor”.

  9. Select “Status”.

  10. Select “EBS brake switch”.

  11. Select all of the SPN 1121 sources.

  12. Service brake released, monitor ServiceRanger and record “EBS brake switch” value (reading) in table.

  13. Depress and hold service brake, monitor ServiceRanger, and record “EBS brake switch” value (reading) in table.

    Notice
    The “EBS brake switch” value may not be indicated in all the sources selected. Only one valid “EBS brake switch” value is required to support UTM.

  14. Compare reading(s) in table.

  • If reading(s) are in range, no problem was found. The intermittent nature of the fault makes it likely that the problem is in the EBS brake switch signal. Contact the OEM for further help troubleshooting the issue.

  • If reading(s) is out of range, refer to OEM guidelines for repair or replacement of the EBS brake switch signal. Go to Step V

Service Brake StateRangeReading(s)
ReleasedBrake pedal is not being pressed
DepressedBrake pedal is being pressed
H
Purpose:Monitor Demanded Brake Pressure.

  1. Key off.

  2. Set vehicle parking brake and chock wheels.

  3. Key on with engine running.

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

  5. Key off.

  6. Key on, engine off.

  7. Connect ServiceRanger.

  8. Select “Data Monitor”.

  9. Select “Pressure”.

  10. Select “Demanded brake pressure”.

  11. Select all of the SPN 8484 sources.

  12. Service brake released, monitor ServiceRanger and record “Demanded brake pressure” value (reading) in table.

  13. Depress and hold service brake, monitor ServiceRanger, and record “Demanded brake pressure” value (reading) in table.

    Notice
    The “Demanded brake pressure” value may not be indicated in all the sources selected. Only one valid “Demanded brake pressure” value is required to support UTM.

  14. Compare reading(s) in table.

  • If reading(s) are in range, no problem was found. The intermittent nature of the fault makes it likely that the problem is in the Demanded brake pressure signal. Contact the OEM for further help troubleshooting the issue.

  • If reading(s) is out of range, refer to OEM guidelines for repair or replacement of the Demanded brake pressure. Go to Step V

Service Brake StateRangeReading(s)
Released0 PSI
Depressed1 PSI - 932 PSI
V
Purpose:Validate repair.

  1. Key off.

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

  3. Key on with engine off.

  4. Clear fault codes using ServiceRanger.

  5. Key on with engine idling.

  6. Check for fault codes using ServiceRanger: