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Lights the check engine lamp
U3549: Hydrogen Tank High Pressure Sensor 1 Circuit
Standardized SAE J2012 code · U35xx codes
What does U3549 mean?
Generic electrical fault on the high-pressure hydrogen tank pressure sensor 1 (typical operating range up to 700 bar on FCEVs).
The code tells you which monitor failed, not which part is broken. Test before replacing parts.
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Common causes
- High Pressure sensor failed
- Low Gateway module routing CAN messages incorrectly
- Low CAN terminating resistor (120 Ω) drifted out of spec
Likelihood is a general estimate across vehicles; your make and model may differ.
Add your car to see reports of U3549 on the same make and model first.
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