Fault Code 136: Transmission Primary Shift Up Selector
J1939: SA 3 SPN 3652 FMI 14
Overview
The Transmission Control Module (TCM) receives the Transmission Requested Gear (PRNDL) message from the Primary and Secondary Automated Driving System (ADS) sources in the ADS 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 the message is not available from one of the ADS sources.
Detection
The TCM monitors Transmission Requested Gear (PRNDL) messages from the Primary and Secondary ADS sources. If messages do not match, the fault is set Active.
Conditions to Set Fault Code Active
FMI 14 – Special Instructions: Primary and Secondary ADS Transmission Requested Gear (PRNDL) messages from do not match for 1 second.
Fallback
FMI 14:
If fault codes 122, 123 and 136 are Active:
- Amber warning lamp on
- Engine cranking prohibited
- Non-Neutral modes prohibited
- PTO mode prohibited
- Hill Start Aid prohibited
- ADS operation prohibited
- If vehicle is moving:
- Red stop lamp on
Conditions to Set Fault Code Inactive
FMI 14: Primary and Secondary ADS Transmission Requested Gear (PRNDL) messages match for 1 second.
Possible Causes
FMI 14:
- Vehicle Components - Vehicle ECU(s)
- Transmission Requested Gear (PRNDL) message not enabled
- 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 136 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 136 is Inactive and there are other Active vehicle or transmission fault codes, troubleshoot all Active fault codes. Go to Step V
If Fault Code 136 is Active or Inactive, refer to OEM guidelines for repair of the vehicle Trans-mission Requested Gear (PRNDL) message (SPN 525). 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 136 sets Active, Go to Step A
If a fault code other than 136 sets Active, troubleshoot per the Fault Code Isolation Procedure Index.