2013 PACCAR MX-13 – P0306 Major decrease in combustion in cylinder 6 relative to the others

Fault code information

1 trip MIL
3 drive cycle recovery
Readiness group – Fuel system
Freeze frame type – Fuel

Description of component(s)

Description, injector (B421, B422, B423, B424, B425, B426)
The fuel injector injects fuel into the combustion chamber.

The amount of fuel injected depends on the duration of the injector solenoid activation in combination with the rail pressure. The longer the solenoid is activated by the PCI ECU at the same rail pressure, the more fuel is injected.

Minimum opening pressure
The injectors do not open below a rail pressure of 180–190 bar [2610–2756 psi].

Injector codes
Every fuel injector is calibrated during production to compensate for any production tolerances. An injector calibration code is present on the housing and connector of the injector. These injector codes must be (re)programmed with DAVIE if one or more injectors have been replaced or fitted in another position, or if the PCI ECU is replaced.

Location of component(s)

Diagnostic condition

This diagnostic runs when the engine is running at a steady speed and load, and the vehicle speed is steady.

Set condition of fault code

The PCI ECU (D420) detects that cylinder 1 is misfiring or the combustion contribution is lower relative to the other cylinders.

Reset condition of fault code

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

Electrical diagram(s)

Technical data

Possible causes

* Faulty cylinder 6 injector (not fueling or under-fueling)
* Loose cylinder 6 injector
* Faulty MX Engine Brake cylinder 6
* Symptom: Slightly reduced power:
* Incorrect valve clearance
* Large imbalance in the drive shaft
* Symptom: Engine block vibration at high load, damaged flywheel
Mechanical defect (for example damaged cam follower or broken valve)

Additional information

* The PCI ECU can detect and identify the cylinder contribution of every cylinder based on analysis of        the rotational speed of the crankshaft using a:
* Cylinder-to-cylinder engine speed comparison, and
* Cylinder-to-cylinder rotational crankshaft acceleration comparison
* This DTC can be the result of another DTC that indicates too high of a combustion contribution of              another cylinder.

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