U355E code meaning
Expander Inlet Pressure Sensor 2 Circuit
Network system Generic code U35xx codes Check engine light
What U355E means
U355E names a circuit fault on pressure sensor 2 at the expander inlet. Conditions there are harsh: cathode exhaust carries the product water of the stack, and Volkswagen notes in a turbine patent that the pressure drop inside the turbine makes water condense even behind a droplet separator, eroding the blades. A Hannover study on fuel cell turbines likewise asks for robustness against droplets and lets the turbine set the cathode operating pressure. Ford describes how wet pressure sensors in a fuel cell can freeze and give no or false signals at a cold start. A second sensor lets the controller spot such a reading. No maker documents U355E publicly. A failure of sensor 2 alone mainly removes this cross-check; together with U355D the expander control is blind and power is likely limited.
U355E at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U355E
- Fuel cell system warning, MIL on
- Fault appears mainly after cold starts
- Reduced power if sensor 1 is affected as well
Common causes of U355E
- Most likelyWiring or connector of sensor 2 corroded by exhaust moisture, open or shorted
- PossibleWater frozen in the sensor port at cold start
- PossibleExpander inlet pressure sensor 2 faulty internally
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Expander inlet pressure sensor 2Sensor wiring
What each part of U355E means
| U | Network system: communication between the control modules (CAN bus). |
| 3 | Reserved range, usually generic. |
| 5E | The exact fault in that area. |
What to do next
- Note U355E and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U355E
What does U355E mean?
U355E means "Expander Inlet Pressure Sensor 2 Circuit". U355E names a circuit fault on pressure sensor 2 at the expander inlet. It is a generic code, so it means the same on every make.
Is it safe to drive with U355E?
Drive gently and only to a workshop. With U355E the car can go into limp mode (reduced power) to protect itself.
Will U355E fail an emissions test?
U355E is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is U355E to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will U355E clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.