CALIPER AS 3C8345 - Caterpillar

Illustration 9 g01425971
Typical DPF (16) Tube (18) Sensor group (19) Thermocouple
Verify that both thermocouples (19) are threaded into the DPF.
Remove both tubes (16) 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 10. Disconnect the harness connector from the sensor group.Note: The ECM will activate a -3 code for all three sensors.
Illustration 10 g01425978
Harness connector for the sensor group (3) Differential pressure (4) Inlet temperature (5) Outlet temperature (6) Return
Connect a jumper wire between the terminals that are listed in Table 2. Wait for a -4 code to become active.Note: Ensure that terminal 6 is used in your harness. If terminal 6 is not used use terminal 2 for this procedure.
Table 2
Code That Applies to Each Terminal on the Harness Connector for the Sensor Group    
Terminals for the Jumper Wire    Code That Should Be Activated    
Jumper wire between terminal 6 (return) and terminal 3 (differential pressure)     -4 Code for Differential Pressure    
Jumper wire between terminal 6 (return) and terminal 4 (inlet temperature)     -4 Code for Inlet Temperature    
Jumper wire between terminal 6 (return) and terminal 5 (outlet temperature)     -4 Code for Outlet Temperature    
Illustration 11 g02155333
Sensor signal wires for the DPF
If a wrong code is activated, the wiring is incorrect. Refer to Illustration 11. Check each wire from the sensor group to the ECM. Identify the wires that are crossed. Correct the wiring.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 the DPF.STOPTest Step 8. Check the Tubing Between the Sensor Group and the DPF
Illustration 12 g01426001
Tubing on a typical DPF
Refer to Illustration 12. Remove the tubing from the DPF.
Check the tubing for obstructions. Remove any obstructions from the tubing.
Install the tubing. Verify that every connection is tight.
Clear the code. Start the engine. Allow the engine idle for 5 seconds. Stop the engine. Verify that the -20 code does not return.Expected Result:The -20 code does not return.Results:
The -20 code does not return. - STOP