Fault Code 116: Secondary Data Link (J1939 B)
J1939: SA 3 SPN 1231 FMI 9, 14
Overview
The Transmission Control Module (TCM) communicates with other vehicle Electronic Control Units (ECUs) via the vehicle J1939 data link. The TCM uses two vehicle J1939 data links to send and receive messages called the Primary Data Link and Secondary Data Link. The Primary Data Link is used by the TCM to communicate with the Engine, ABS, Body, and other vehicle ECUs during normal operation. The Secondary Data Link is used as a backup in the event that the Primary Data Link is inoperative. The Secondary Data Link is connected to the TCM at the 20-Way TCM Body Harness Connector.
Detection
The TCM monitors messages broadcast over the vehicle Secondary Data Link (J1939 B). If engine or vehicle messages are not received or in error, the fault is set active.
Conditions to Set Fault Code Active
FMI 9 – Abnormal Update Rate: Vehicle Secondary Data Link (J1939 B) messages not received for 5 seconds.
FMI 14 – Special Instructions: Vehicle Secondary Data Link (J1939 B) Engine messages not received for 5 seconds while the TCM is receiving messages from other vehicle ECUs.
Fallback
FMI 9, 14:
- Amber warning lamp on
- If Fault Code 115, 165 or 176 is Active and the transmission is in neutral:
- Non neutral modes prohibited
- PTO Mode prohibited
- If Fault Code 115, 165 or 176 is Active, the vehicle is moving or the transmission is in a gear higher than the lowest available start gear:
- Red stop lamp on
- Clutch engagement prohibited, vehicle may coast to a stop
- Transmission downshifts to lowest available start gear
Conditions to Set Fault Code Inactive
FMI 9: Valid vehicle Secondary Data Link (J1939 B) messages received for 10 seconds.
FMI 14: Valid vehicle Secondary Data Link (J1939 B) Engine messages received for 10 seconds.
Possible Causes
FMI 9:
- Secondary Data Link (J1939 B) not configured correctly in the TCM
- Vehicle Secondary Data Link (J1939 B)
- Wiring shorted to ground, shorted to power or open
- Bent, spread, or loose terminals
- Excessive electrical noise
- Missing or additional terminating resistors
- Other Vehicle ECU(s)
- Internal failure
FMI 14:
- Vehicle Secondary Data Link (J1939 B) – Between Engine ECU and TCM
- Wiring shorted to ground, shorted to power or open
- Bent, spread, or loose terminals
- Excessive electrical noise
- Missing or additional terminating resistors
- Engine ECU
- Not powering up
- Internal failure
Additional Tools
- Endurant HD Service Manual TRSM0950
- Digital Volt Ohm Meter (DVOM)
Component Identification
 |
1. 20-Way TCM Vehicle Harness Connector 2. 20-Way TCM Body Harness Connector 3. Transmission Control Module (TCM) 4. 9-Way Type 2 Diagnostic Connector (In Cab) |
 |
1. Transmission Control Module (TCM) 2. 20-Way TCM Vehicle Harness Connector 3. 20-Way TCM Body Harness Connector 4A. 9-Way Type 2 Diagnostic Connector (OEM-Specific Primary Data Link FG) 4B. 9-Way Type 2 Diagnostic Connector (OEM-Specific Primary Data Link CD) |
 |
Fault Code 116 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 116 FMI 9 is Active or Inactive, Go to Step B
If Fault Code 116 FMI 14 is Active, Go to Step N
If Fault Code 116 FMI 14 is Inactive, an intermittent condition may exist on the Secondary Data Link with the following:
- Power up issue with the Engine ECU
- Vehicle Secondary Data Link to the Engine ECU
- Fault(s) reported from the Engine ECU
- Refer to OEM guidelines for repair or replacement of vehicle Secondary Data Link (J1939A) or Engine ECU. Go to Step V
Key off.
Allow TCM to perform a complete power down.
Key on with engine off.
Connect ServiceRanger.
Go to “Configuration”.
Select “Vehicle”.
Record the “Secondary J1939 Baud Rate” "Current Value" in table.
Record the “Secondary J1939 Baud Rate” installed on the vehicle in table.
Note: The vehicle's Secondary J1939 Baud Rate (250K or 500K) is determined by OEM. Refer to the OEM regarding the Secondary J1939 Baud Rate installed on the vehicle.
Compare reading(s) in table.
If “Secondary J1939 Baud Rate” is not configured correctly, select the correct configuration from the “New Value” drop down, select “Apply” and follow on screen prompt. Go to Step V
If FMI 9 is Active and “Secondary J1939 Baud Rate” is configured correctly, Go to Step C
| Location | Secondary J1939 Baud Rate |
|---|---|
| TCM (ServiceRanger) | |
| Vehicle |
Key off.
Refer to the OEM and identify the TCM location on the Vehicle Secondary Data Link (J1939 B) at the 9-Way Diagnostic Connector.
If the TCM is on 9-Way Diagnostic Connector Pin C and Pin D, go to Go to Step D
If the TCM is on 9-Way Diagnostic Connector Pin H and Pin J, Go to Step I
Key on with engine off.
Measure voltage between 9-Way Diagnostic Connector Pin C and Pin A. Record reading in table.
Measure voltage between 9-Way Diagnostic Connector Pin D and Pin A. Record reading in table.
Record the total voltage by adding together the voltage readings.
Compare reading(s) in table.
If readings are in range, Go to Step E
If readings are out of range, refer to OEM guidelines for repair or replacement of vehicle Secondary Data Link (J1939 B). Go to Step V
| Pins | Range | Reading(s) |
|---|---|---|
| C to A | N/A | |
| D to A | N/A | + |
| Total Voltage | 4.5–5.5 V | = |
Key off.
Measure resistance between 9-Way Diagnostic Connector Pin C and Pin D. Record reading in table.
Compare reading(s) in table.
If readings are out of range, refer to OEM guidelines for repair or replacement of vehicle Secondary Data Link (J1939 B). Go to Step V
If readings are in range, Go to Step F
| Pins | Range | Reading(s) |
|---|---|---|
| C to D | 50–70 Ohms |
Key off.
Disconnect the 20-way TCM Body Harness Connector.
Inspect the 20-Way TCM Body Harness Connector, verify the connector is free from contamination and corrosion; the terminals are not bent, spread or loose; and there is no damage to the connector body.
Inspect the TCM side of the 20-Way TCM Body Harness Connector, verify the connector is free from contamination and corrosion; the terminals are not bent, spread or loose; and there is no damage to the connector body.
If contamination or damage is found, refer to OEM guidelines for repair or replacement of the 20-Way TCM Body Harness Connector. Go to Step V
If no contamination or damage is found, Go to Step G
Key off.
Measure resistance between 20-Way TCM Body Harness Connector Pin 7 and Pin 8. Record reading in table.
Compare reading(s) in table.
If readings are out of range, refer to OEM guidelines for repair or replacement of vehicle Secondary Data Link (J1939 B). Go to Step V
If readings are in range, Go to Step H
| Pins | Range | Reading(s) |
|---|---|---|
| 7 to 8 | 50–70 Ohms |
Key off.
Reconnect all connectors and verify that all components are properly installed.
Key on with engine off.
Connect ServiceRanger.
Retrieve and record the transmission fault codes, FMIs, occurrences, and timestamps.
If Fault Code 116 is Inactive, an intermittent wiring issue exists within the vehicle Secondary Data Link (J1939 B), refer to OEM guidelines for repair or replacement. Go to Step V
If Fault Code 116 is Active and no fault was found with the vehicle Secondary Data Link (J1939 B), replace the Transmission Control Module (TCM). Go to Step V
Note: Troubleshooting indicates no fault found with the wiring or connections to the TCM. Ensure an intermittent issue does not exist with the wiring or connections.
Key on with engine off.
Measure voltage between 9-Way Diagnostic Connector Pin H and Pin A. Record reading in table.
Measure voltage between 9-Way Diagnostic Connector Pin J and Pin A. Record reading in table.
Record the total voltage by adding together the voltage readings.
Compare reading(s) in table.
If readings are in range, Go to Step J
If readings are out of range, refer to OEM guidelines for repair or replacement of vehicle Secondary Data Link (J1939 B). Go to Step V
| Pins | Range | Reading(s) |
|---|---|---|
| H to A | N/A | |
| J to A | N/A | + |
| Total Voltage | 4.7–5.3 V | = |
Key off.
Measure resistance between 9-Way Diagnostic Connector Pin H and Pin J. Record reading in table.
Compare reading(s) in table.
If reading is out of range, refer to OEM guidelines for repair or replacement of vehicle Secondary Data Link (J1939 B). Go to Step V
If reading is in range, Go to Step K
| Pins | Range | Reading(s) |
|---|---|---|
| H to J | 50–70 Ohms |
Key off.
Disconnect the 20-way TCM Body Harness Connector.
Inspect the 20-Way TCM Body Harness Connector, verify the connector is free from contamination and corrosion; the terminals are not bent, spread or loose; and there is no damage to the connector body.
Inspect the TCM side of the 20-Way TCM Body Harness Connector, verify the connector is free from contamination and corrosion; the terminals are not bent, spread or loose; and there is no damage to the connector body.
If contamination or damage is found, refer to OEM guidelines for repair or replacement of the 20-Way TCM Body Harness Connector. Go to Step V
If no contamination or damage is found, Go to Step L
Key off.
Measure resistance between 20-Way TCM Body Harness Connector Pin 7 and Pin 8. Record reading in table.
Compare reading(s) in table.
If readings are out of range, refer to OEM guidelines for repair or replacement of vehicle Secondary Data Link (J1939 B). Go to Step V
If readings are in range, Go to Step M
| Pins | Range | Reading(s) |
|---|---|---|
| 7 to 8 | 50–70 Ohms |
Key off.
Reconnect all connectors and verify that all components are properly installed.
Key on, engine off.
Connect ServiceRanger.
Retrieve and record the transmission fault codes, FMIs, occurrences, and timestamps.
If Fault Code 116 is Inactive, an intermittent wiring issue exists within the vehicle Secondary Data Link (J1939 B), refer to OEM guidelines for repair or replacement. Go to Step V
If Fault Code 116 is Active and no fault was found with the vehicle Secondary Data Link (J1939 B), replace the Transmission Control Module (TCM). Go to Step V
Note: Troubleshooting indicates no fault found with the wiring or connections to the TCM. Ensure an intermittent issue does not exist with the wiring or connections.
Key off.
Locate and disconnect the Engine ECU vehicle harness connector containing the vehicle Secondary Data Link (J1939 B).
Note: Refer to OEM guidelines for Engine ECU vehicle harness connector location, connector removal, and J1939 High (+) and J1939 Low (-) connector pin locations.
Measure resistance between Engine ECU vehicle harness connector Pin J1939 High (+) and Pin J1939 Low (-). Record reading in table.
Compare reading(s) in table.
If readings are out of range, refer to OEM guidelines for repair or replacement of vehicle Secondary Data Link (J1939 B). Go to Step V
If readings are in range, Engine ECU has continuity to the vehicle Secondary Data Link (J1939 B). A condition may exist with the following:
- Power up issue with the Engine ECU
- Fault message from the Engine ECU
Contact OEM for further diagnostic instructions. Go to Step V
| Pins | Range | Reading(s) |
|---|---|---|
| J1939 High (+) to J1939 Low (-) | 50–70 Ohms |
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 116 sets Active during operation, Go to Step A
If a fault code other than 116 sets Active, troubleshoot per the Fault Code Isolation Procedure Index