PACCAR MX (2004 Emissions) Fault Code: P1574 Exhaust Gas Pressure Before Turbine – Data Erratic, Intermittent or Incorrect

PACCAR MX (2004 Emissions) Fault Code: P1574 Exhaust Gas Pressure Before Turbine – Data Erratic, Intermittent or Incorrect

SET CONDITIONS:
The PCI ECU (D420) detects that the measured pressure before turbine is above 6.0 bar [87 psi] during an engine braking event.

DIAGNOSTIC CONDITION:
This diagnostic runs continuously when the ignition is on.

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

POSSIBLE CAUSES:
1. Malfunction of the VTG turbocharger control, BPV valve control, or EGR valve control. Check for relevant DTCs.
2. Pressure sensor before turbine deviation

ADDITIONAL INFORMATION:
1. An automated transmission can request a shift assist event on the engine in order to reduce the engine speed quickly. The engine can use the engine brake to achieve this.

2. The PCI ECU uses the pressure before turbine for, among other things, controlling the VTG turbocharger, EGR valve position, BPV valve position and engine braking.

3. The pressure before turbine is measured by the pressure sensor before turbine (F826).