Possible Causes

Possible causes are:

• Damaged DPFEGR sensor (DTCs P1400 or P1401).
• Damaged PCM (DTCs P1400 or P1401).
• DPFEGR SIG open (DTC P1401).
• DPFEGR SIG shorted to GND (DTC P1400).
• DPFEGR SIG shorted to PWR (DTC P1401).
• SIG RTN open (DTC P1401).
• VREF shorted to GND (DTC P1400).
• VREF shorted to PWR (DTC P1401).