PACCAR MX (2004 Emissions) Fault Code: P1048 Air Mass Flow – Data Valid but Too High, During Overrun

PACCAR MX (2004 Emissions) Fault Code: P1048 Air Mass Flow – Data Valid but Too High, During Overrun

SET CONDITIONS:
The VTG turbocharger actuator (L037) detects:
1. A difference between the required and actual actuator motor position of more than 8.9% for more than 35 seconds with
2. An actuator effort of more than 38% with
3. An actuator temperature of more than 5?C

DIAGNOSTIC CONDITION:
This diagnostic runs continuously when the engine is in SCR heating mode.

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

POSSIBLE CAUSES:
1. After an actuator installation: VTG turbocharger actuator initialization procedure was not executed or was executed incorrectly.
2. Soot build-up on the turbocharger nozzle ring mechanism

This soot can be removed when:
– the learn sweep is performed several times. Therefore, key the ignition on and off
several times or
– when the engine is operated under high load (soot burned off)

3. Faulty actuator or turbocharger nozzle ring mechanism
4. Faulty VTG turbocharger

ADDITIONAL INFORMATION:
1. The VTG turbocharger actuator controls the actuator motor position, and therefore, the turbocharger nozzle ring and the effort to move the nozzle ring.
2. After this DTC has become active, P1727 and P2563 can also become active.