U3565

Code

Generic U — Network/User

Hydrogen Supply Line A Pressure Sensor 2 Circuit

Brand: Generic

Type: U — Network/User

Views: UK: 23 EN: 32 RU: 25

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Page language: EN

Causes

Damaged or chafed wiring harness for Pressure Sensor 2
Corroded, loose, or contaminated connector at the sensor or control module
Pressure sensor internal failure
Short to battery voltage or to ground in the signal/reference/ground circuit
Poor or missing sensor ground or reference voltage
Blown fuse or faulty relay supplying sensor/ECU power

Symptoms

Check Engine/Service light or hydrogen-system warning lamp illuminated
Reduced hydrogen system performance or limp-home mode (system dependent)
Incorrect or implausible pressure reading in live data (stuck, pegged high/low, or erratic)
Difficulty starting or loss of power (depending on system control strategy)
Fault remains or returns after clearing codes (intermittent faults may appear sporadically)

What to check

Read all stored and pending codes; record freeze frame and relevant live data
Perform visual inspection of sensor, connector, and harness for damage, corrosion, or contamination
Inspect and verify fuses and relays supplying the sensor and related control modules
Wiggle test harness/connectors while monitoring live data to reproduce intermittent behavior
Backprobe sensor connector and verify reference voltage, ground continuity, and signal voltage with key ON (engine off)
Measure resistance/continuity between sensor ground and chassis ground

Signal parameters

Reference (excitation) voltage usually ~5 V (verify factory spec before testing)
Signal voltage should vary with pressure (typical 0.5–4.5 V range for analog sensors; check vehicle spec)
Sensor ground should show low resistance to chassis ground (
No continuity between signal wire and battery positive or chassis ground (indicates short)
Live-data update rate and value range expected per manufacturer specification (compare to known-good)

Diagnostic algorithm

Safety first: follow hydrogen-system safety procedures — ventilate area, eliminate ignition sources, and isolate hydrogen supply if required by vehicle procedures.
Retrieve and record all DTCs, freeze frame and live sensor data with a scan tool.
Visually inspect the sensor, connector and wiring for physical damage, contamination, or disconnected terminals. Repair any obvious damage.
With connector connected, backprobe the reference, signal and ground pins. Verify reference voltage and ground presence with key ON. Confirm signal voltage changes while applying known pressure or operating conditions (consult factory test pressure).
If reference or ground is missing/incorrect, trace and repair power/ground circuit: check fuses, relays, ground points and continuity to the control module.
If signal is shorted to power or ground, isolate sections of the harness and repair or replace damaged wiring. Disconnect sensor and re-check for short between signal circuit and battery or ground.
Perform a wiggle/road test to check for intermittent faults. Monitor live data while manipulating the harness and connector.
If wiring and connectors test good, swap in a known-good sensor (if available) or bench-test the suspect sensor per manufacturer procedures.
If sensor and wiring pass, inspect and test the control module input pin for proper operation and continuity. Consider module software updates or module replacement only after eliminating wiring/sensor causes.
Clear codes and retest vehicle under the conditions that previously set the code. Document repairs and monitor for reoccurrence.