CHANGEOVER AR 3C8346 - Caterpillar

Illustration 8 g01426519
Typical DPF
(21) Thermocouple
(18) Tube
Verify that both thermocouples (21) are threaded into the DPF.
Remove both tubes (18) and check the tubes for obstructions.
Install the tubes. Verify that all four nuts for the tubes are tight.
Inspect the exhaust piping between the ARD and the inlet to the DPF. Verify that the exhaust piping is free of holes and of cracks and that all clamps are securely fastened.
Clear the -2 code.
Turn the keyswitch to the OFF position.
Turn the keyswitch to the ON position. Wait for 15 seconds.
Start the engine.
Check for a recurrence of the -2 code. Expected Result:The -2 code does not return.Results:
Yes - The -2 code does not return. The -2 code was caused by a mechanical problem.STOP
No - The -2 code returns. There is not a mechanical problem. There is a wiring problem.Repair: Perform the following procedure:
Refer to Illustration 9. Disconnect the harness connector from the sensor group. Note: The ECM will activate a -3 code for all three sensors.
Illustration 9 g01754913
Harness connector for the DPF
(3) Differential pressure
(2) Return
(4) Inlet temperature
(5) Outlet temperature
Connect a jumper wire between the terminals that are listed in Table 7. Wait for a -4 code to become active.
Table 7
Code That Applies to Each Terminal on the Harness Connector for the DPF
Terminals for the Jumper Wire Code That Should Be Activated
Jumper wire between terminal 2 (return) and terminal 3 (differential pressure) -4 Code for Differential Pressure
Jumper wire between terminal 2 (return) and terminal 4 (inlet temperature) -4 Code for Inlet Temperature
Jumper wire between terminal 2 (return) and terminal 5 (outlet temperature) -4 Code for Outlet Temperature
If a wrong code is activated, the wiring is incorrect. Refer to Illustration 7. Identify the problem with the wiring. Make the necessary repairs. If the correct code is activated for all three signal terminals, the wiring is OK. There is a wiring problem inside the sensor group. Replace the sensor group.
Perform the following procedure in order to verify that your repair has solved the problem. Clear the codes for the sensor group.
Turn the keyswitch to the OFF position.
Turn the keyswitch to the ON position. Wait for 15 seconds.
Start the engine. Verify that there are no -2 codes for the sensors for DPF. STOPTest Step 8. Troubleshoot the Incorrect Signal
If the vehicle has a single DPF, disconnect the harness connector from the sensor group. if the vehicle has two filters, perform the following procedure in order to determine the appropriate DPF:
Illustration 10 g01439608
Identifying the diesel particulate filters
Gain access to a harness connector for either sensor group. Disconnect the harness connector from the sensor group. Use the information in Illustration 10 in order to determine the appropriate DPF for the diagnostic code.
Disconnect the appropriate harness connector.
Clean the harness connector and the electrical connector on the sensor group. Both of the connectors must be clean and dry.
Connect the electrical connectors.
Turn the keyswitch to the OFF position. Wait for five seconds. Turn the keyswitch to the ON position. Wait for ten seconds. Expected Result:The -20 code or the -21 code clears automatically .Results:
The -20