Endurant HD
TRTS0950 EN-US
|
November 2024 - B

Fault Code 125: Primary ADS Operation Status

J1939: SA 3 SPN 20870 FMI 9,11, 13, 14, 19

Overview

The Transmission Control Module (TCM) receives the vehicle’s primary Automated Driving System (ADS) Operation Status message from a vehicle Electronic Control Unit (ECU) over the Primary Data Link (J1939A). This information is used to determine transmission operation.

The TCM also receives a secondary Automated Driving System (ADS) Operation Status message from a vehicle Electronic Control Unit (ECU) over the Primary Data Link (J1939A). This redundancy allows the TCM to maintain transmission function in a degraded mode in the event either message is not available.

Detection

The TCM monitors primary ADS Operation Status messages. If messages are not received or are invalid, the fault is set Active.

Conditions to Set Fault Code Active

FMI 9 - Abnormal Update Rate: Primary ADS Operation Status message not received for 5 seconds.

FMI 11 - Root Cause Unknown: Primary and secondary ADS Operation Status messages do not match for 5 seconds.

FMI 13 - Out of Calibration: Primary ADS Operation Status messages not available for 5 seconds.

FMI 14 - Special Instructions: Primary and secondary ADS Operation Status message sources not configured.

FMI 19 - Received Network Data in Error: Primary ADS Operation Status messages invalid for 5 seconds.

Fallback

FMI 9, 11, 13, 14, 19:

If fault codes 125 and 126 are Active:

  • Amber warning lamp on
  • Coast Mode and Neutral Coast prohibited
  • Urge to Move and Creep Mode prohibited
  • ADS Operation prohibited

Conditions to Set Fault Code Inactive

FMI 9, 13, 19: Primary ADS Operation Status messages received and valid for 10 seconds.

FMI 11: Primary ADS Operation Status messages received and valid for 1 second.

FMI 14: Key cycle and fault condition no longer exists.

Possible Causes

FMI 9, 11, 13, 14, 19:

  • Vehicle Components - Vehicle ECU(s)
    • Primary ADS Operation Status 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 125 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 125 is Inactive and there are other Active vehicle or transmission fault codes, troubleshoot all Active fault codes. Go to Step V

  • If Fault Code 125 FMI 9, 11, 19 is Active or Inactive, refer to OEM guidelines for repair of the vehicle ADS Operation Status message (SPN 20870). Go to Step V

  • If Fault Code 125 FMI 13 is Active, refer to OEM and enable vehicle primary ADS Operation Status message (SPN 20870). Go to Step V

  • If Fault Code 125 FMI 13 is Inactive, Go to Step V

  • If Fault Code 125 FMI 14 is Active, Contact Eaton Cummins Automated Transmission Technologies for further diagnostic instructions. For Help Line phone numbers, go to Contact Information. Go to Step V

  • If Fault Code 125 FMI 14 is Inactive, Go to Step V

V
Purpose:Verify Repair.

  1. Key off.

  2. Reconnect all connectors and verify 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.