PACCAR MX (2004 Emissions) Fault Code: P1058 Inlet Air Pressure in Inlet Manifold – Data Valid but Too Low

PACCAR MX (2004 Emissions) Fault Code: P1058 Inlet Air Pressure in Inlet Manifold – Data Valid but Too Low

SET CONDITIONS:
The PCI ECU (D420) detects that the boost pressure is lower than expected.

DIAGNOSTIC CONDITION:
This diagnostic runs continuously when the following is true:
1. The engine is operating at a steady load, with a minimum actual fuel quantity of 175 mg/stroke
2. The engine is running in one of the following engine modes: ‘Standard’, ‘SCR high efficiency’ or ‘SCR super high efficiency’

CORRESPONDING OBD READINESS MONITOR:
VTG monitor

RESET CONDITION:
This DTC will change to inactive after the diagnostic runs and passes.

REPAIR VERIFICATION:
1. Clear all DTCs.
2. Test drive or operate the vehicle to meet the following conditions:
– Corresponding readiness monitor displays ‘Ready’
– Diagnostic conditions are met
– Set conditions are met
3. Did the DTC come back? (Can be pending, inactive or active)
– No, repair successful
– Yes, repair unsuccessful

POSSIBLE CAUSES:
1. Leakage of the pressurized inlet air circuit
2. Damaged compressor wheel of the VTG turbocharger

ADDITIONAL INFORMATION:
1. The fuel quantity can be monitored using the diagnostic service tool monitor signal: ‘Fuel quantity (Actual)’.
2. The diagnostic has detected that the boost pressure is too low compared to the measured pressure before turbine.