03 December, 2025PACCAR MX (2004 Emissions) Fault Code: P151C Aftertreatment System – DEF Level Too Low PACCAR MX (2004 Emissions) Fault Code: P151C Aftertreatment System – DEF Level Too Low SET CONDITIONS:The DEF level is less than 20% of the DEF tank volume. DIAGNOSTIC CONDITION:This diagnostic runs continuously when the ignition is on. RESET CONDITION:This DTC becomes inactive after the ignition is keyed on and the volume in the DEF tank is above the set condition value. POSSIBLE CAUSES:Empty DEF tank ADDITIONAL INFORMATION:The driver has been informed by a flashing warning. Delen op Facebook Opent in een nieuw venster. Twitteren op Twitter Opent in een nieuw venster. Pinnen op Pinterest Opent in een nieuw venster. Terug naar blog