Fault Code 156: Brake Pedal Position
J1939: SA 3 SPN 521 FMI 9, 13, 19
Overview
The Transmission Control Module (TCM) receives the vehicle’s Brake Pedal Position message over the Primary Data Link. This information is used to determine transmission operation.
Detection
The TCM monitors the Brake Pedal Position message. If a failure is detected the fault is set Active.
Conditions to Set Fault Code Active
FMI 9 - Abnormal Update Rate: Brake Pedal Position message not received for 5 seconds.
FMI 13 - Out of Calibration: Brake Pedal Position message not available for 5 seconds.
FMI 19: Brake Pedal Position message invalid for 5 seconds.
Fallback
FMI 9, 13, 19:
- Amber warning lamp on
- Urge to Move and Creep Mode prohibited
- Hill Start Aid prohibited
Conditions to Set Fault Code Inactive
FMI 9, 13, 19: Brake Pedal Position message.
Possible Causes
FMI 9, 13, 19:
- Vehicle Components
- Module(s)
- Brake Pedal Position
- Primary Data Link
Additional Tools
- None
Fault Code 156 Troubleshooting
Record the transmission fault codes, FMIs, occurrences, and timestamps from the Service Activity Report created during the Diagnostic Procedure.
If Fault Code 156 is Inactive and there are other Active vehicle or transmission fault codes, troubleshoot all Active fault codes. Go to Step V
If Fault Code 156 FMI 13 is Active, refer to OEM and enable vehicle Brake Pedal Position SPN 521. Go to Step V
If Fault Code 156 FMI 13 is Inactive, Go to Step V
If Fault Code 156 FMI 9 or 19 is Active or Inactive, refer to OEM guidelines regarding Brake Pedal Position repair or replacement. 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 156 sets Active during operation, Go to Step A
If a fault code other than 156 sets Active, troubleshoot per Fault Code Isolation Procedure Index.