HARNESS AS-CHASSIS 2677969 - Caterpillar

The aftertreatment identification module sends a digital signal to the engine ECM in order to ensure that the correct CEM is installed to the engine.If more than 25 hours (total operating hours) have been accumulated on the engine, the aftertreatment identification module will cease to send the signal. The diagnostic codes that are listed in Table 1 will be disabled.
Illustration 1 g02133314
Schematic for the aftertreatment identification module
Test Step 1. Check for Active Diagnostic Codes
Establish communication between the Caterpillar Electronic Technician (ET) and the ECM.
Download the "Product Summary Report" from the engine ECM before performing any troubleshooting or clearing diagnostic trouble codes. Results:
Active 3468-2 - A 3468-2 diagnostic code is active. Proceed to Test Step 4.
Active 3468-8 - A 3468-8 diagnostic code is active. Proceed to Test Step 2.
Active 3468-14 - A 3468-14 diagnostic code is active. Proceed to Test Step 4.Test Step 2. Inspect the Electrical Connectors and the Wiring
Illustration 2 g02133313
Location of the components for the aftertreatment identification module
(1) CEM identification plate
(2) Aftertreatment identification module
Illustration 3 g02133315
Location of the J2/P2 ECM connector
(3) J2/P2 ECM connector
Thoroughly inspect the connector for the aftertreatment identification module (2) and J2/P2 connector (3). Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Inspect the connector for the aftertreatment identification module. Refer to Troubleshooting, "Electrical Connectors - Inspect" for details.
Illustration 4 g02133316
Terminal locations at the P2 ECM connector for the aftertreatment identification module
(P2-73) Signal for the aftertreatment identification module
(P2-82) Return
(P2-92) Analog supply
Illustration 5 g01994856
Terminal locations at the connector for the aftertreatment identification module
(Terminal 1) Analog supply
(Terminal 3) Aftertreatment identification module
(Terminal 6) Return
Perform a 45 N (10 lb) pull test on each of the wires in the connectors that are associated with the aftertreatment identification module.
Check the torque of the allen head screw on each of the ECM connectors. Refer to Troubleshooting, "Electrical Connectors - Inspect" for the correct torque values.
Check the harness for abrasion and pinch points from the aftertreatment identification module back to the ECM. Expected Result:All connectors, pins, and sockets are coupled and/or inserted and the harness and wiring are free of corrosion, abrasion, and pinch points.Results:
OK - All connectors, pins, and sockets are correctly coupled and/or inserted. The harness is free of corrosion, abrasion, and pinch points. Proceed to Test Step 3.
Not OK - There is a problem with the connectors and/or wiring.Repair: Repair the connectors or the harness and/or replace the connectors or the harness. Ensure that all of the seals are correctly in place and ensure that the connectors are coupled.Use Cat ET in order to clear all logged diagnostic codes and then verify that the repair has eliminated the fault.STOPTest Step 3. Measure the Supply Voltage at the Connector for the Aftertreatment Identification Module
Turn the keyswitch to the OFF position.
Disconnect the aftertreatment identification module from the harness.
Turn the keyswitch to the ON position.
Measure the voltage at the plug for the aftertreatment identification module from the terminal for the analog supply to the terminal for the return. Expected Result:The supply voltage at the connector is 5.0 0.2 VDC.Results:
OK - The supply voltage is