What does it mean?
P1104 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Differential Pressure Sensor Intake Manifold Pressure Too Low (Bank 1) .
Symptoms
- Clear loss of power, especially when accelerating or climbing a hill
- Vehicle drops into limp mode with the boost limited
- Check engine light on with a low pressure value stored in the freeze frame
- Whistling or hissing from the engine bay under load where a pipe has come loose
- Increased fuel consumption and, on diesels, visible smoke
- Engine feels normal at idle but flat as soon as load is applied
Likely causes
- Leaking charge air pipe, split hose or a loose clamp between the turbocharger and the manifold
- Cracked intercooler or a failed intercooler pipe seal
- Blocked or oil-fouled pressure sensing hose or port feeding the sensor
- Faulty differential pressure sensor giving a permanently low reading
- Boost control fault such as a wastegate stuck open or a sticking actuator
- Heavily restricted air filter or a collapsed intake duct starving the engine
- Signal or ground wiring fault at the sensor connector
How to fix it
- Compare the sensor reading with barometric pressure with the ignition on and the engine stopped; the two should be close
- Watch actual against requested manifold pressure in live data during a road test to see the size of the deviation
- Inspect all charge pipes, hoses and clamps for splits, oil traces and loose joints, then pressure test the intake tract if nothing is obvious
- Remove and check the sensor port and its hose for oil, soot or a blockage; clean carefully without damaging the element
- Check the air filter and intake ducting for restriction or collapse
- Test the sensor supply, ground and signal wiring at the connector before condemning the sensor
- Repair the leak or replace the sensor as indicated, then confirm boost follows the requested value across the rev range