The Transmission Control Module (TCM) receives the vehicle’s Brake Application Pressure signal message over the Primary Data Link. This information is used to determine transmission operation.
The Transmission Control Module (TCM) monitors the Brake Application Pressure signal. If the message is not received or invalid, the fault is set active.
FMI 9 - Abnormal Update Rate: Brake Application Pressure signal not received for 5 seconds.
FMI 13 – Out Of Calibration: Brake Application Pressure message not available for 5 seconds.
FMI 14 – Special Instructions: Brake Application Pressure signal not received after a launch for 1 second.
FMI 19 – Received Network Data In Error: Brake Application Pressure message invalid for 5 seconds.
All FMIs:
Note: Refer to OEM regarding vehicle fallback modes.
FMI 9, 13, 14, 19: Brake Application Pressure signal received and valid for 10 seconds.
All FMIs:
Note: Refer to OEM for troubleshooting a failed system.
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 161 is Inactive and there are other Active vehicle or transmission fault codes, troubleshoot all Active fault codes. Go to Step V
If Fault Code 161 FMI 13 is Active, refer to OEM and enable vehicle Brake Application Pressure SPN 116. Go to Step V
If Fault Code 161 FMI 13 is Inactive, Go to Step V
If Fault Code 161 FMI 9, 14 or 19 is Active or Inactive, Go to Step B
Key on with engine running.
Allow air pressure to build to governor cut off.
Key off.
Key on with engine off.
Connect ServiceRanger.
Go To “Data Monitor”.
Select “Pressure”.
Select “Brake application pressure”.
Select all of the “- 116” SPN sources.
Note: Not all sources will indicate a value.
Monitor 116 - Brake application pressure value. Record reading in table.
Depress and hold service brake.
Monitor 116 - Brake application pressure value. Record reading in table.
Compare reading(s) in table.
If readings are out of range, refer to OEM guidelines for repair or replacement of the Brake application pressure signal message. 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 Brake application pressure signal message. Contact OEM for further diagnostic instructions. Go to Step V
Service Brake State | Parameter | Range | Reading(s) |
---|---|---|---|
Released | 116 - Brake Application Pressure | 0 PSI | |
Depressed | 116 - Brake Application Pressure | Greater Than 0 PSI |
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 161 sets Active during operation, Go to Step A
If a fault code other than 161 sets Active, troubleshoot per Fault Code Isolation Procedure Index.