CYL-HYD-YM 4259374 - Caterpillar

Table 1
Diagnostic Trouble Codes
J1939 Code Code Description Comments
4376-5 Aftertreatment #1 DEF Return Valve : Current Below Normal This code indicates there is problem with the DEF pump reverting valve or the Pump Electronic Tank Unit (PETU) wiring harness.
4376-6 Aftertreatment #1 DEF Return Valve : Current Above Normal This code indicates there is problem with the DEF pump reverting valve or the PETU wiring harness.
Follow the troubleshooting procedure in order to identify the root cause of the problem. Note: 372-5260 Test Kit is required for completing this procedure.
Illustration 1 g03171637
Table 2
Troubleshooting Test Steps Values Results
1. Check for Opens in the PETU Wiring Harness for the Reverting Valve
A. Turn the keyswitch to the OFF position for 2 minutes. The keyswitch must be OFF for 2 minutes to allow the DEF pump to purge, reset the code, and reset the Diesel Exhaust Fluid Controller (DCU).
B. Disconnect the PETU wiring