Invalid Signal from Aftertreatment Fuel Pressure Sensor

There's a sensor that measures the pressure of the fuel in the aftertreatment system, and it's either broken or getting a signal that's way off from normal.

The engine control module (ECM) detects that the voltage from the aftertreatment fuel pressure sensor is out of its expected range, typically below 0.1 volts or above 4.9 volts.

Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.

1. 11. Check the wiring and connectors for the aftertreatment fuel pressure sensor for any visible damage or loose connections. Repair as necessary. Decision: If wiring is good, proceed to step 2; if not, repair it and retest.
2. 22. Test the voltage at the sensor connector with the key on and engine off. You should see a voltage between 0.5 - 4.5 volts. Decision: If voltage is in range, sensor is likely good; if not, replace the sensor.
3. 33. If the sensor tests good, check the fuel system pressure using a pressure gauge. Expected pressure is between 35-50 psi. Decision: If pressure is low, check for clogged filters or fuel supply issues; if normal, inspect ECM for software updates or faults.

• Faulty aftertreatment fuel pressure sensor
• Wiring issue or poor connection to the sensor
• Clogged fuel filter affecting fuel pressure

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