DESCRIPTION:

This Fault Code Sets when the Diesel Oxidations Catalyst (DOC) Inlet Pressure is 35 kPa (5 psi) Greater Than the Diesel Particulate Filter (DPF) Outlet Pressure for more than 10 Seconds.

The ACM monitors the DOC inlet pressure sensor & DPF outlet pressure sensor. This will cause a 25% derate/power loss.

TROUBLESHOOTING:

1. Check for other fault codes, if codes 3609/3 or 3609/4 are present. Diagnose those codes first.
2. Using DDDL go to service routines> SCR & DPF voltages

• Monitor DOC inlet pressure sensor voltage pin 87. If voltage is NOT between 0.44-0.56 volts replace the DOC inlet pressure sensor.
• Monitor DPF outlet pressure sensor voltage pin 72. If voltage is NOT between 0.44-0.56 volts replace DPF outlet pressure sensor.

3. If all sensors check out okay, perform a Low temp by disconnecting DEF metering unit connector then navigating to the Service routines>DFP then perform a low temp regen. Then monitor DOC inlet temp & DPF outlet temp sensor readings:

• If the DOC oullet temp sensor reading follows the DOC inlet temp sensor reading, replace the failed DPF. Regen to verify the repair
• If the DOC outlet temp sensor reading does NOT follow the DOC inlet temp sensor reading, replace the failed DOC. Regen to verify the repair.