U355A code meaning
Charge Air Cooler Outlet Pressure Sensor 1 Circuit
Network system Generic code U35xx codes Check engine light
What U355A means
U355A concerns the first of two pressure sensors behind the charge air cooler, where compressed and cooled air heads for the humidifier and the stack. This is the pressure the system really regulates: in a Nissan patent a sensor between intercooler and water recovery unit is the feedback for compressor torque and the outlet pressure valve, and the controller caps this pressure so that compressor and humidifier stay below their heat limits. Toyota takes its counterpart behind compressor and intercooler as the delivery pressure for the surge check. No public manufacturer document names U355A. An open or shorted circuit takes away the main pressure feedback; expect a fuel cell warning and reduced output. Where sensor 2 (U355B) is fitted it can serve as a fallback.
U355A 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 U355A
- Fuel cell system warning, MIL on
- Noticeably reduced power
- Compressor speed fluctuates or stays high
Common causes of U355A
- Most likelyOpen, short or corrosion in wiring or connector of sensor 1
- PossiblePressure sensor 1 faulty internally
- Less likelyShared 5 V supply or ground faulty (often with other sensor codes)
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Cac outlet pressure sensor 1Sensor wiring
What each part of U355A means
| U | Network system: communication between the control modules (CAN bus). |
| 3 | Reserved range, usually generic. |
| 5A | The exact fault in that area. |
What to do next
- Note U355A 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 U355A
What does U355A mean?
U355A means "Charge Air Cooler Outlet Pressure Sensor 1 Circuit". U355A concerns the first of two pressure sensors behind the charge air cooler, where compressed and cooled air heads for the humidifier and the stack. It is a generic code, so it means the same on every make.
Is it safe to drive with U355A?
Drive gently and only to a workshop. With U355A the car can go into limp mode (reduced power) to protect itself.
Will U355A fail an emissions test?
U355A 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 U355A to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will U355A clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.