5032876 JOHNSON BOLT (6X35mm)

Table 1
J1939 Code and Description CDL Code and Description Comments
561-31
TCS/ASR Engine Control Active 48-1
Backup ECM Took Control The secondary Electronic Control Module (ECM) detected that the primary ECM is having difficulties controlling the engine.
The secondary ECM assumes control of the engine.
The code is logged. Probable Causes
Codes
Voltage
Heartbeat
Engine overspeedThe primary Electronic Control Module (ECM) periodically broadcasts a message over the CAN data link and CDL Data Links that communicates the condition of the primary ECM. This message is recognized by the secondary ECM as the ECM heartbeat status of the primary ECM. If the heartbeat message is lost or unreadable, the secondary ECM will assume control of the engine.The secondary ECM continuously transmits a ready status message over the CAN data link and CDL Data Links. As long as the secondary ECM is broadcasting a status of "Ready", the secondary ECM is eligible to take control of the engine.Note: The power to the engine must be cycled prior to allowing the primary ECM to resume control of the engine.Recommended Actions
Table 2
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Look for active codes that are associated with the system for the event code.
Codes
Result: An associated code is active.
Repair: Troubleshoot any associated codes before continuing with this test.
Result: A code is active or logged.
Proceed to Test Step 2.
2. Check the Battery Voltage to the Primary Electronic Control Module (ECM)
A. Establish communication with the primary ECM.
B. If communication with the primary ECM cannot be established, verify that voltage is present at the primary ECM. If voltage is not present at the keyswitch input or battery voltage at the primary ECM, refer to Troubleshooting, "Electrical Power Supply - Test" for additional information.
Voltage
Result: The voltage check is OK.
Proceed to Test Step 3.
Result: The voltage check is NOT OK.
Repair: Repair the low voltage condition.
If the problem is not resolved, proceed to Test Step 3.
3. Check the Loss of Primary ECM Heartbeat Message
The secondary ECM will assume control of the engine if the primary ECM heartbeat signal to the secondary ECM is interrupted.
The secondary ECM will remain in control of governing until keyswitch power to the primary ECM has been cycled.
Heartbeat
Result: The primary ECM is OK.
Proceed to Test Step 4.
Result: The primary ECM is NOT OK.
Repair: Repair or replace the faulty ECM.
If the problem is not resolved, proceed to Test Step 4.
4. Check for Fuel Injector Solenoid Codes
If multiple diagnostic codes for the injector solenoids are active at the same time, then the primary ECM will terminate.
The secondary ECM will assume control of governing if the primary ECM heartbeat signal to the secondary ECM is interrupted.
Codes
Result: Fuel injector codes are not active.
Proceed to Test Step 5.
Result: Fuel injector codes are active.
Repair: Refer to Troubleshooting, "Injector Solenoid - Test" for additional information.
If the problem is not resolved, proceed to Test Step 5.
5. Check for Engine Overspeed Condition
If an engine overspeed occurs, the secondary ECM will assume control of governing.
The secondary ECM will stop fuel injection to the engine.
The secondary ECM will remain in control of governing until keyswitch power to the primary ECM has been cycled.
Overspeed
Result: There is an overspeed condition.
Repair: Determine the cause for the engine overspeed. Refer to Troubleshooting, "Engine Overspeeds" for additional information.
Verify that the repair eliminated the problem.
If the procedure did not correct the issue, contact your Cat dealer Technical Communicator (TC). For further assistance, your TC can confer with the Dealer Solutions Network (DSN).