Fault Code 173: Engine Requested Speed
J1939: SA 3 SPN 898 FMI 12
Overview
The Transmission Control Module (TCM) sends and receives Engine Requested Speed messages to and from the engine Electronic Control Unit (ECU) over the Primary Data Link (J1939A). This message is used by the TCM to confirm the Engine ECU is receiving and responding to the requested speed.
Detection
The TCM monitors Engine Requested Speed messages. If messages are not received or are invalid, the fault is set Active.
Conditions to Set Fault Code Active
FMI 12 – Bad Intelligent Device: TCM inappropriately commanded engine speed.
Fallback
FMI 12:
- Torque above idle prohibited
- Accelerator pedal may be unresponsive
- Vehicle may not move
Conditions to Set Fault Code Inactive
FMI 12: Key cycle and fault condition no longer exist.
Possible Causes
FMI 12:
- TCM
- Software issue
- Internal failure
Additional Tools
- None
Fault Code 173 Troubleshooting
Set vehicle parking brake and chock wheels.
Record transmission fault codes, FMIs, occurrences, and timestamps from Service Activity Report created during the Diagnostic Procedure.
If Fault Code 173 is Inactive and there are other Active vehicle or transmission fault codes, troubleshoot all Active fault codes. Go to Step V
If Fault Code 173 FMI 12 is Active or Inactive, Contact Eaton Cummins Automated Transmission Technologies for further diagnostic instructions. For Help Line phone numbers, go to Contact Information. Go to Step V
Key off.
Reconnect all connectors and verify all components are properly installed.
Key on with engine off.
Connect ServiceRanger.
Go To “Fault Codes”.
Select “Clear All Faults”.
Operate vehicle and attempt to reset the fault code or duplicate the previous complaint.
Check for fault codes using ServiceRanger.
If no fault codes set and vehicle operates properly, test complete.
If Fault Code 173 sets Active, Go to Step A
If a fault code other than 173 sets Active, troubleshoot per Fault Code Isolation Procedure Index.