C27 and C32 Engines for Caterpillar Built Machines Caterpillar

Aftertreatment Identification Module - Test

Usage:

990K A9P

This procedure covers the following codes:

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Table 1
Diagnostic Trouble Codes
CDL Code and Description	Conditions which Generate the Code	System Response
3468-2 Aftertreatment #1 Identification Number Module: Erratic, Intermittent, or Incorrect	The installed Clean Emissions Module (CEM) is not a certified match with the engine. Diagnostic codes 3468-8 or 3468-14 are not active. No 2131 diagnostic codes are active. The Electronic Control Module (ECM) has been powered for 2 seconds.	“This is a violation of the emissions regulations, and may result in severe fines and/or legal action if not corrected immediately.” Do not operate the engine with the active fault. Engine power is derated.
3468-8 Aftertreatment #1 Identification Number Module: Abnormal Frequency Pulse Width or Period	No signal is detected from the aftertreatment identification module. No 2131 diagnostic codes are active. The ECM has been powered for 2 seconds.	Do not continue to operate the engine with the active fault. Engine power is derated.
3468-14 Aftertreatment #1 Identification Number Module: Special Instruction	The signal from the aftertreatment identification module is invalid. Diagnostic code 3468-8 is not active. The ECM has been powered for 2 seconds.	Do not continue to operate the engine with the active fault. Engine power is derated.

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.

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Illustration 1	g02133314
Schematic for the aftertreatment identification module

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Table 2
Troubleshooting Test Steps	Values	Results
1. Check for Codes A. Establish communication between the Cat^® Electronic Technician (ET) and the ECM. B. Determine if a code is active or logged.	Codes	Result: A 3468-2 diagnostic code is active. Proceed to Test Step 4. Result: A 3468-8 diagnostic code is active. Proceed to Test Step 2. Result: A 3468-14 diagnostic code is active. Proceed to Test Step 4.

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Illustration 2	g02133313
Location of the components for the aftertreatment identification module (1) CEM identification plate (2) Aftertreatment identification module

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Illustration 3	g02133315
Location of the J2/P2 ECM connector (3) J2/P2 ECM connector

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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

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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

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Table 3
Troubleshooting Test Steps	Values	Results
2. Inspect the Electrical Connectors and Wiring A. Turn the main disconnect switch to the OFF position. 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.	Electrical 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 Test Step 3.
3. Measure the Supply Voltage at the Connector for the Aftertreatment Identification Module A. Turn the keyswitch to the OFF position. B. Disconnect the aftertreatment identification module from the harness. C. Turn the keyswitch to the ON position. D. Measure the voltage at the plug for the aftertreatment identification module from the terminal for the analog supply to the terminal for the return.	5.0 ± 0.2 VDC	Result: The supply voltage is correct. Proceed to Test Step 4. Result: The supply voltage at the connector is not 5.0 ± 0.2 VDC. There is a problem in the supply circuit for the aftertreatment identification module. Repair: Refer to Troubleshooting, "Sensor Supply - Test" for information that is related to troubleshooting the supply circuit. If the problem is not resolved, proceed to Test Step 4.
4. Manually Enter the Aftertreatment Identification Information Note: Factory Passwords are required for this procedure. A. Confirm that a certified CEM is installed on the engine. B. Record the "CEM Serial Number" and the "Configuration Group" from the CEM identification plate. C. Contact your local Cat dealer for a list of approved CEM configurations for your engine. Note: Contact your Technical Communicator (TC), if necessary. D. Verify that the CEM is a certified match with the engine.	CEM	Result: The CEM is a certified match with the engine. Repair: Perform the following procedure: 1. Establish communication between Cat ET and the ECM . Refer to Troubleshooting, "Electronic Service Tools", if necessary. 2. Use the "Service" drop-down menu to navigate to the "Configuration" screen. 3. Program the "Factory Installed Aftertreatment #1 Identification Number" with the serial number from the CEM identification plate. If the problem is not resolved, proceed to Test Step 4. Result: The CEM is not a certified match to the engine. Repair: Replace the CEM with a certified match to the engine. Refer to Disassembly and Assembly for removal and installation procedures. When the new CEM is installed, the aftertreatment identification module will begin communicating with the ECM and the diagnostic code will be cleared. The engine ECM will only communicate with the CEM if there are less than a total of 100 operating hours on the engine. If there are more than 100 operating hours on the engine, the CEM information must be programmed into the ECM by using Cat ET. Verify that the repair eliminated the problem.