U3565
Hydrogen Supply Line A Pressure Sensor 2 Circuit.
- Generic
- Network
- Generic code
- High severity
How this code is built
- U
- SystemNetwork
- 3
- Defined bySAE, the same on every car
- 5
- AreaNetwork area 5
- 65
- FaultThe specific fault in that area
What it means
U3565 is defined as a fault in the Hydrogen Supply Line A Pressure Sensor 2 circuit, so it only applies to hydrogen fuel cell or hydrogen-fuelled vehicles. The control unit saw a signal or data from this second pressure sensor that was missing, out of range or implausible. It may also have disagreed with other pressure readings on the hydrogen supply line. Exact setting conditions and sensor location depend on the make, model and system layout.
Symptoms
- Warning light on the dashboard, possibly with a fuel system or fuel cell warning message
- Reduced power or the vehicle going into a limited-performance mode
- Vehicle failing to start or the fuel cell system shutting down
- Hydrogen supply or fuel cell system fault shown alongside other stored codes
- Inaccurate or erratic hydrogen pressure or range readings
Possible causes
- Faulty hydrogen supply line pressure sensor 2likely
- Damaged wiring, chafing or a short or open circuit to the sensorlikely
- Corroded, loose or contaminated connector at the sensor or control unitpossible
- Real pressure fault in the supply line, such as a regulator or valve fault or a leak, causing a mismatch with the sensor readingpossible
- Fault in the control unit that reads the sensor, or a network communication problem passing the data onrare
- Outdated or faulty control unit calibration, if the manufacturer has identified it as a known causerare
How to diagnose
- Read all stored and pending codes and the freeze frame data, noting any other hydrogen, fuel cell or network codes.
- Check for manufacturer service bulletins and the model-specific procedure for this code, as sensor position and test values vary.
- Visually inspect the sensor, its wiring and connectors for damage, corrosion, moisture or chafing, without disturbing any high-pressure hydrogen components.
- Check for hydrogen leaks and for any other warning signs, following the manufacturer's safety procedure. Only a technician trained in hydrogen systems should do this.
- Compare the live pressure readings from sensor 2 with the other supply line pressure sensors to see if it is stuck, drifting or implausible.
- Test the sensor supply voltage, earth and signal wiring for continuity, shorts and resistance against the manufacturer's specification.
- Check for network communication faults between the sensor's control unit and the main system controller.
- After repair, clear the code, then road test and recheck for the code returning.
How to fix
- Repair or replace damaged wiring and connectors in the sensor circuit.
- Replace the hydrogen supply line pressure sensor 2 if it is proven faulty, using the manufacturer's procedure for hydrogen system components.
- Repair any hydrogen leak or supply line fault that is causing the pressure mismatch, using trained personnel.
- Repair any network or control unit fault found, and update the software only if the manufacturer lists it as the fix for this code.
- Clear the code and confirm it does not return after a full drive cycle.
Can I keep driving?
Avoid driving the vehicle until the fault is diagnosed, as it involves the hydrogen supply and a real pressure fault or leak could be unsafe. If a hydrogen smell or leak is suspected, stop, keep away from ignition sources and get specialist help.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.