SEAL-RING 3S1259 - Caterpillar

Use this procedure to troubleshoot a problem with the exhaust temperature sensors. Also, use this procedure if one of the following diagnostic codes is active or easily repeated.
Table 1
Diagnostic Codes Table    
J1939 Code and Description    Conditions which Generate this Code    System Response    
173-9
Engine Exhaust Gas Temperature : Abnormal Update Rate     The Integrated Sensing Module (ISM) has not received several messages that were expected from the exhaust temperature sensors over the CAN data link.     The code is logged.
The alarm output is activated.    The ISM is an electronic monitoring system used to monitor exhaust temperatures. The module monitors the following thermocouples:
Thermocouple for the exhaust port of each cylinderThe ISM reads each of these temperatures and sends this information via the CAN data link to the ECM and the optional remote control panel.If the ECM cannot communicate with the ISM, the ECM activates a diagnostic code related to identify the problem. The most likely cause of the diagnostic code is a problem with an electrical connector or a harness. The next likely cause is a problem with the ISM.Terminating resistors must be connected to each end of the CAN data link. The terminating resistors improve the communication signal between the devices. If there is an intermittent diagnostic code for any of the devices connected to the CAN data link, check the terminating resistors. One of the terminating resistors is in the control panel. The other terminating resistor is inside the ECM control box. If the engine is not equipped with a remote panel, the other terminating resistor will be connected at the far end of interconnect harness. Refer to Troubleshooting, "CAN Data Link - Test" for details related to troubleshooting the data link circuit.This troubleshooting procedure may generate additional diagnostic codes. Correct the cause of the original diagnostic code before continuing. You clear the diagnostic codes after the problem is resolved.
Illustration 1 g03818797
Illustration 2 g03330519
(1) ISM P2/J2 (2) ISM P1/J1
Table 2
Troubleshooting Test Steps    Values    Results    
1. Check for Codes
A. Connect Cat® Electronic Technician (ET) to the service tool connector.
B. Determine if a code is active or logged.
   
Codes
   
Result: A 173-9 code is active or logged.
Repair: The ECM has detected a problem with the communication between the ECM and the sensor.
Proceed to Test Step 3.
Result: A code is not active or logged.
Proceed to Test Step 2.
   
2. Inspect the Electrical Connectors and the Wiring
A. Ensure that the electrical power has been removed from the engine.
B. Thoroughly inspect the connectors. Refer to Troubleshooting, "Electrical Connectors-Inspect" for additional information.
C. Perform a 45 N (10 lb) pull test on the connector wires.
D. Check the harness for abrasions and pinch points.
   
Connectors and Wiring
   
Result: The connectors and wiring appear to be OK.
Proceed to Test Step 3.
Result: There is a problem with the connectors and/or wiring.
Repair: Repair or replace the connectors or wiring. Ensure that all of the seals are properly in place and ensure that the connectors are coupled.
If the problem is not resolved, proceed to