PACCAR MX (2004 Emissions) Fault Code: P104D Exhaust Gas Pressure Before Turbine – Data Valid but Too High

PACCAR MX (2004 Emissions) Fault Code: P104D Exhaust Gas Pressure Before Turbine – Data Valid but Too High

SET CONDITIONS:
The PCI ECU (D420) detects that the measured pressure before turbine is higher than the expected pressure before turbine for more than 50 seconds.

DIAGNOSTIC CONDITION:
This diagnostic runs:
1. When the engine speed is between 1000 and 1700 rpm and
2. When the engine is running at a steady load and
3. When the coolant temperature is above 50°C [122°F] and
4. The engine mode is SCR high efficiency or standard or protection.

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:
1. Clogged EGR system
2. Blocked exhaust system
3. Restricted pressure sensor before turbine tube
4. Pressure sensor before turbine deviation
5. Air leakage between intercooler and inlet manifold

ADDITIONAL INFORMATION:
1. The measured pressure before turbine is compared with an expected pressure before turbine.
2. The pressure before turbine is measured by the pressure sensor before turbine (F826).