2013 PACCAR MX-13 – P0168 Fuel temperature – Data valid but too high, most severe

Fault code information

1 trip red fault lamp
3 drive cycle recovery
Readiness group – none
Freeze frame type – Fuel

Description of component(s)

The fuel temperature is measured in the low-pressure fuel supply gallery between the common rail pump units.
Effect on the system:
* Preventing automatic fuel module water draining activation when the fuel temperature is very low           (the water present may be frozen).
* Limitation of the engine torque when the fuel temperature is too high.

Location of component(s)

Diagnostic condition

This diagnostic runs continuously when the ignition is on.

Set condition of fault code

The PCI ECU (D420) detects that the fuel temperature is more than 98°C [208°F] for more than 30 seconds.

Reset condition of fault code

This DTC changes to inactive when the fault is no longer detected. To validate the repair, key off the ignition for at least 15 seconds, key on again. Then start the engine and let it idle for more than 30 seconds.

Electrical diagram(s)

Technical data

Component check, fuel temperature sensor (F803)
• Key off the ignition.

• Disconnect connector F803
• Measure on component connector F803

Possible causes

* Restriction in the fuel to tank return circuit or faulty fuel pressure regulating valve.
Check the fuel pressure according to the prescribed job.
* Excessive dumping of fuel from the common rail through common rail pressure release valve (L094).

Additional information

* The low-pressure fuel temperature is measured by the fuel temperature sensor (F803).
* Engine torque is reduced with this DTC active.

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