Fault Code 191: Front Axle Right Wheel Speed
J1939: SA 3 SPN 906 FMI 13, 19
Overview
The Transmission Control Module (TCM) receives the vehicle’s Front Axle Right Wheel Speed message over the Primary Data Link. The transmission utilizes this input as a redundant wheel speed.
Detection
The Transmission Control Module (TCM) monitors the Front Axle Right Wheel Speed message. If message is not received or invalid, the fault is set active.
Conditions to Set Fault Code Active
FMI 13 – Out of Calibration: Front Axle Right Wheel Speed message not available for 10 seconds.
FMI 19 – Received Network Data in Error: Front Axle Right Wheel Speed message invalid for 10 seconds.
Fallback
All FMIs:
Note: Refer to OEM for troubleshooting a failed system. Brake system fallback modes will vary.
- Amber warning lamp on
- No degraded performance
Conditions to Set Fault Code Inactive
All FMIs: Front Axle Right Wheel Speed message received and valid for 10 seconds.
Possible Causes
All FMIs:
- Vehicle ECU Front Axle Right Wheel Speed Message
- Not available
- Not valid
Fault Code 191 Troubleshooting
Set vehicle parking brake and chock wheels.
Record the transmission fault codes, FMIs, occurrences, and timestamps from the Service Activity Report created during the Diagnostic Procedure.
If Fault Code 191 is Inactive and there are other Active vehicle or transmission fault codes, troubleshoot all Active fault codes. Go to Step V
If Fault Code 191 FMI 13 is Active, refer to OEM and enable vehicle Front Axle Right Wheel Speed SPN 906. Go to Step V
If Fault Code 191 FMI 13 is Inactive, Go to Step V
If Fault Code 191 FMI 19 is Active or Inactive, there is a fault with the Front Axle Right Wheel Speed message sent from a vehicle module. Contact OEM for further diagnostic instructions. Go to Step V
Key off.
Reconnect all connectors and verify that 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 the vehicle operates properly, test complete.
If Fault Code 191 sets Active during operation, Go to Step A
If a fault code other than 191 sets Active, troubleshoot per Fault Code Isolation Procedure Index.