Exhaust Aftertreatment Fuel Pressure Sensor Circuit Low

Where it lives

For P20DF, the circuit described runs through the sensor. The description of P20DF reports a fault at the sensor.

Check these first

• Low aftertreatment fuel pressure from a weak pump
• A clogged aftertreatment fuel filter
• A short to ground in the sensor signal circuit
• A failing aftertreatment fuel pressure sensor
• A restriction in the fuel lines or aftertreatment injector

What to do next

1. Check aftertreatment fuel pressure against spec
2. Inspect the sensor wiring for a short to ground
3. Check the aftertreatment fuel filter for clogging
4. Read the sensor signal with a scan tool and compare it to a gauge
5. Replace the fuel pressure sensor if the signal stays low
6. Clear the code and retest

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