PACCAR Fault Code P3918: DEF Pressure – Data Valid But Too Low, Absolute Pressure

Code details

Manufacturer

PACCAR (Kenworth & Peterbilt)

Applies to

PACCAR MX-13 (2017–2020)

Fault code

P3918

J1939 SPN

3226

FMI

11 — Root cause not known

Truck models in source

Kenworth T680, T880, W900, T800; Peterbilt 579, 389, 567, 367

What to do next

• Read active and inactive codes with the OEM service tool and note the occurrence count.
• FMI 11 tells the shop the type of failure to test for: root cause not known.
• Have a heavy-duty diesel technician confirm the fault against the engine or chassis service manual before replacing parts.

Related fault codes

• PACCAR Fault Code P3918 — NOx Sensor After Catalyst – NOx Signal Malfunction
• PACCAR Fault Code P3873 — CAN Communication – Message (AT1IOGC1) Time-Out From NOx Sensor After Catalyst
• PACCAR Fault Code P3914 — NOx Sensor After Catalyst – Data Not Rational, Drifted High
• PACCAR Fault Code P3917 — NOx Sensor After Catalyst – Error
• PACCAR Fault Code P3921 — CAN Communication – Timeout From NOx Sensor After Catalyst
• PACCAR Fault Code P3922 — NOx Sensor After Catalyst – Value Not Changing When Expected
• PACCAR Fault Code P3924 — NOx Sensor After Catalyst – Out of Calibration
• PACCAR Fault Code P3928 — NOx Sensor After Catalyst – O₂ Concentration, Too Low