PACCAR MX (2004 Emissions) Fault Code: P0471 Exhaust Gas Pressure Before Turbine – Data Erratic, Intermittent or Incorrect, at Ignition On

SET CONDITIONS:
The PCI ECU (D420) detects that the measured pressure before turbine sensor reading differs more than 0.36 bar [5.2 PSI] from the average of other engine pressure sensor readings for more than five seconds.

DIAGNOSTIC CONDITION:
This diagnostic runs when the ignition is switched on (NO engine start) and the ambient temperature is more than -20°C [-4°F].

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
This DTC changes to inactive when the fault is no longer detected.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the diagnostic conditions and set conditions.
3. Did the DTC come back? (Can be pending, inactive or active)
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
Pressure sensor before turbine deviation

ADDITIONAL INFORMATION:
For this diagnostic, the pressure sensor before turbine (F826) reading is compared with an average of other engine pressure sensor readings.