ENGINE AR-PRIMARY 5030968 - Caterpillar

Background Information
The Integrated Sensing Module (ISM) monitors type K thermocouples at each cylinder exhaust port and at the inlets and outlets for both turbochargers. The ISM can also calculate the average temperature for all cylinders. Temperature readings of the thermocouples are available over the CAN data link for use by the Electronic Control Module (ECM) and by other modules. The temperatures can be viewed on Cat® Electronic Technician (ET).The ISM generates an event code for each of the following programmable conditions:
High exhaust temperature
High deviation of an exhaust port temperature
Low deviation of an exhaust port temperature
High inlet temperature to the turbocharger turbine
High outlet temperature from the turbocharger turbineA diagnostic code is generated by the ISM for the circuit of any thermocouple that is shorted to the +Battery side, shorted to ground, or open.Logged diagnostic codes provide a historical record. Before you begin this procedure, use Cat ET to print the logged codes to a file.This troubleshooting procedure may generate additional diagnostic codes. Keep your mind on correcting the cause of the original diagnostic code. Clear the diagnostic codes after the problem is resolved.
Illustration 1 g03792844
Illustration 2 g03330476
(Terminal 1) Sensor signal
(Terminal 2) Sensor return
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 -3 code is active.
Proceed to Test Step 2.
Result: A -4 code is active.
Proceed to Test Step 3.
Result: For a code that is logged, but not currently active.
Proceed to Test Step 4.
2. Create a Short at the Sensor Connector
A. Turn the main disconnect switch to the OFF position.
B. Disconnect the sensor with the active -3 code.
C. Install the jumper wire between the following terminals at the sensor connector:
- Terminal 1 (sensor signal) and Terminal 2 (sensor return)
D. Connect Cat ET.
E. Use Cat ET to monitor the following:
- -4 code
F. Turn the main disconnect switch to the OFF position.
Create a Short
Result: The -3 code remains active.
Repair: There is an open in the wiring harness. Repair or replace the wiring harness.
Verify that the repair eliminated the problem.
Result: A -4 code became active.
Repair: The wiring harness is OK. Replace the sensor.
Verify that the repair eliminated the problem.
3. Create an Open at the Sensor Connector
A. Turn the main disconnect switch to the OFF position.
B. Disconnect the sensor with the active -4 code.
C. Connect Cat ET.
D. Use Cat ET to monitor the following:
- -3 code
E. Turn the main disconnect switch to the OFF position.
Create an Open
Result: The -4 code remains active.
Repair: There is an open in the wiring harness. Repair or replace the wiring harness.
Verify that the repair eliminated the problem.
Result: A -3 code became active.
Repair: The wiring harness is OK. Replace the sensor.
Verify that the repair eliminated the problem.
4. Perform the Wiggle Test
Carefully following this procedure is the best way to identify the root cause of an intermittent problem.
A. Connect Cat ET.
B. Use CAT ET to perform the following test:
- "Wiggle Test"
C.