17925A15 Mariner KEY SWITCH ASSEMBLY

Table 1
Event Code
J1939 Code and Description Conditions which Generate this Code System Response
561-12 TCS/ASR Engine Control Active : Failure The secondary ECM detected that the primary ECM is having difficulties controlling the engine. The code is logged.
The secondary assumes control of the engine. Probable Causes
Battery voltage to the primary ECM
Loss of primary ECM heartbeat message
Diagnostic codes for the injector solenoidsThe primary ECM periodically broadcasts a message over the data link 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 data link. 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
Note: The procedures have been listed in order of probability. Complete the procedures in the order of the listed test steps.Recommended Actions
Table 2
Troubleshooting Test Steps Values Results
1. Check for Codes
A. Establish communication between Caterpillar Electronic Technician (ET) and the Electronic Control Module (ECM).
C. Determine if the diagnostic trouble code that directed to this procedure is present.
D. Monitor the diagnostic codes on Cat ET. Check for active diagnostic codes.
561-12
Result: There are active codes.
Repair: Troubleshoot any active codes before continuing with this procedure.
Verify that the repair eliminated the problem.
Result: A 561-12
Proceed to Test Step 2.
Result: No active codes
STOP
2. Check the Battery Voltage to the Primary ECM
A. Connect Caterpillar Electronic Technician (ET). 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".
Voltage
Result: The systems check is OK.
Proceed to Test Step 3.
Result: The systems check is NOT OK
Repair: Repair the leak or restriction.
Verify that the repair eliminated the problem.
3. Check the Loss of Primary ECM Heartbeat Message
A. The secondary ECM will assume control of the engine if the primary ECM heartbeat signal to the secondary ECM is interrupted.
B. 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.
Verify that the repair eliminated the problem.
4. Check for Multiple Diagnostic Codes for the Injector Solenoids
A. 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.
B. Check for active diagnostic codes or for logged diagnostic codes for the injector solenoids.
C. If diagnostic codes are present or if diagnostic codes were logged, refer to Troubleshooting, "Injector Solenoid - Test".
Codes
Result: The injectors are OK.
Proceed to Test Step 5.
Result: The injectors are NOT OK.
Repair: Repair or replace the injectors.
Verify that the repair eliminated the problem.
5. Check for Engine Overspeed Condition
A. If an engine overspeed occurs, the secondary ECM will assume control of governing.
B. 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"
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).