U3576
Stack Differential Pressure Sensor Circuit.
- Generic
- Network
- Generic code
- Medium severity
How this code is built
- U
- SystemNetwork
- 3
- Defined bySAE, the same on every car
- 5
- AreaNetwork area 5
- 76
- FaultThe specific fault in that area
What it means
U3576 is defined here as a Stack Differential Pressure Sensor Circuit fault. A control unit monitoring a stack (typically a fuel cell stack, on vehicles that have one) saw a signal from the differential pressure sensor that was missing, implausible or outside its expected range. Because it is a U-code, the signal may also be received over the vehicle network from another module. Exact sensor location, monitored circuit and set conditions depend on the vehicle and system, so check the manufacturer's data for the model.
Symptoms
- Warning light or system fault message on the dashboard
- Reduced power or limp-mode operation
- Reduced performance or efficiency from the stack system
- System shutdown or refusal to start or ready the vehicle
- Other stored codes for the stack, its cooling or its gas supply
Possible causes
- Damaged, corroded or loose wiring or connector at the differential pressure sensorlikely
- Faulty differential pressure sensor (internal failure or drift)likely
- Blocked, leaking or disconnected sensing lines or ports to the sensorpossible
- Supply voltage or ground fault affecting the sensor circuitpossible
- Real pressure imbalance across the stack (restriction or flow fault) causing an implausible readingpossible
- Fault in the control unit or network communication carrying the sensor signalrare
How to diagnose
- Read all stored and pending codes and record freeze frame data, noting any related stack, cooling or network codes
- Check for technical service bulletins or known software updates for the model and system
- Visually inspect the sensor, its wiring and connectors for damage, corrosion, moisture, chafing or pin push-out
- Inspect the sensing lines and ports for blockage, cracks, leaks or loose connections
- Check the sensor's supply voltage, reference and ground against the manufacturer's specification
- Compare live sensor data with the expected value at rest and under load, and check that the signal responds correctly
- Test the signal wiring for open circuit, short to ground or short to supply, and check for network communication faults
- Follow the manufacturer's procedure to confirm the real pressure condition before condemning the sensor or control unit
How to fix
- Repair or replace damaged wiring, terminals or connectors, then clear the code and retest
- Replace the differential pressure sensor if it fails testing
- Clear, refit or replace blocked, leaking or damaged sensing lines
- Correct supply or ground faults found in the sensor circuit
- Repair any underlying flow or restriction fault in the stack system that is causing the abnormal reading
- Update or repair the control unit software or hardware only if the manufacturer identifies it as a known cause
Can I keep driving?
The vehicle may be driveable, but it could drop into limp mode or shut down the stack system, so get it checked soon. High-voltage or fuel system work should only be done by suitably trained technicians. Stop driving if a serious warning appears or power is lost.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.