Faulty hydrogen supply line A pressure sensor 1, including internal sensor drift or failure.; Damaged, chafed, or corroded wiring in the sensor circuit, such as an open or short to ground or power.; Loose or corroded electrical connector at the pressure sensor or at the control module.; High resistance in the sensor ground circuit, causing a biased pressure signal.; Contamination or blockage in the hydrogen supply line affecting the actual pressure seen by the sensor.; A software or calibration issue in the control module that misinterprets the sensor signal.; A failing control module driver circuit for the sensor reference voltage or signal return.

DTC codes / U35xx · Network communication / U3564

U3564Hydrogen Supply Line A Pressure Sensor 1 Circuit

Q: What does code U3564 mean?

Hydrogen Supply Line A Pressure Sensor 1 Circuit. U3564 is a manufacturer-specific network code indicating that the hydrogen supply line A pressure sensor 1 circuit has reported a fault to the control module responsible for the hydrogen delivery system. The computer has detected an abnormal voltage, current, or signal rationality condition on the sensor's circuit, meaning the sensor is not reporting a plausible pressure reading for the hydrogen supply line.

U3564 is a manufacturer-specific network code indicating that the hydrogen supply line A pressure sensor 1 circuit has reported a fault to the control module responsible for the hydrogen delivery system. The computer has detected an abnormal voltage, current, or signal rationality condition on the sensor's circuit, meaning the sensor is not reporting a plausible pressure reading for the hydrogen supply line.

SystemNetwork

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaNetwork communication

Symptoms you may notice

Illumination of the malfunction indicator lamp (MIL) on the dashboard, often with no other noticeable symptoms.
Reduced power or a limp-home mode if the control module defaults to a safe hydrogen pressure strategy.
Rough running, hesitation, or misfire under load if hydrogen delivery is improperly regulated.
A message on the driver information display warning of a hydrogen system fault or reduced performance.
Inability to refuel or a refueling station fault if the system detects an implausible pressure reading.
In rare cases, a no-start condition if the control module refuses to enable the hydrogen supply.

Common causes, most likely first

Faulty hydrogen supply line A pressure sensor 1, including internal sensor drift or failure.
Damaged, chafed, or corroded wiring in the sensor circuit, such as an open or short to ground or power.
Loose or corroded electrical connector at the pressure sensor or at the control module.
High resistance in the sensor ground circuit, causing a biased pressure signal.
Contamination or blockage in the hydrogen supply line affecting the actual pressure seen by the sensor.
A software or calibration issue in the control module that misinterprets the sensor signal.
A failing control module driver circuit for the sensor reference voltage or signal return.

How to diagnose and fix it

Connect a scan tool and record all stored codes, freeze-frame data, and live pressure sensor readings to confirm the fault is current.
Visually inspect the pressure sensor, its connector, and the wiring harness for damage, corrosion, or loose pins.
Measure reference voltage, signal voltage, and ground continuity at the sensor connector with a digital multimeter (DMM) and compare to manufacturer specifications.
Perform a wiggle test on the harness while watching live sensor data to reveal intermittent wiring faults.
Check the hydrogen supply line for physical damage, kinks, or contamination that could cause a genuine pressure deviation.
If the circuit tests good, substitute a known-good sensor and recheck live data to confirm the sensor is the cause.
Clear codes and perform a road test or system relearn procedure, then verify the code does not return.

Hydrogen Sensor Circuit Checks Most Techs Miss

A common oversight is replacing the pressure sensor before checking the ground circuit; a high-resistance ground can skew the signal voltage and set U3564 even with a perfectly good sensor.
Intermittent U3564 codes often trace to a chafed wire near a bracket or heat source rather than the sensor itself, so a thorough harness inspection with a wiggle test is essential.
Some vehicles set U3564 when the hydrogen tank pressure is genuinely low or the supply line is restricted, so always verify actual pressure with a mechanical gauge before condemning electronics.
The code can be stored by a control module that has lost communication with the sensor over a serial data bus, so check for other communication codes that might indicate a network issue rather than a sensor fault.
After repairs, some manufacturers require a hydrogen system leak test or pressure calibration procedure; skipping this step can cause the code to reset immediately.

Can I keep driving with U3564?

If the vehicle drives normally and only the warning light is on, you can usually continue driving to a workshop, but avoid heavy loads and refueling until the fault is diagnosed. If the vehicle enters limp mode or shows a hydrogen system warning, stop driving and have it towed to avoid potential safety risks.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.