PACCAR MX (2004 Emissions) Fault Code: P006C Inlet Air Pressure Before Compressor – Data Erratic, Intermittent or Incorrect, at Ignition On

PACCAR MX (2004 Emissions) Fault Code: P006C Inlet Air Pressure Before Compressor – Data Erratic, Intermittent or Incorrect, at Ignition On

SET CONDITIONS:
The PCI ECU (D420) detects that the measured pressure reading of the humidity sensor differs more than 0.06 bar [0.9 PSI] from the average of other engine pressure sensor readings for more than five seconds.

DIAGNOSTIC CONDITION:
This diagnostic runs:
1. When the ignition is keyed on (NO engine start), and
2. Ambient temperature is more than -20°C [-4°F]

CORRESPONDING OBD READINESS MONITOR:
None

RESET CONDITION:
To validate the repair, key on the ignition (NO engine start) and wait for 10 seconds to allow the system to power up and the diagnostics to run.

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:
Humidity sensor deviation

ADDITIONAL INFORMATION:
1. The humidity sensor is a smart sensor that communicates with the PCI ECU via E-CAN. The sensor measures the following three properties of the drawn in precompressor (VTG turbo charger) air in the inlet air pipe:
– Relative humidity
– Pressure
– Temperature

2. For this diagnostic, the pressure reading of the humidity sensor (F852) is compared with an average of other engine pressure sensor readings.