U355C code meaning
Charge Air Cooler Outlet Temperature Sensor Circuit
Network system Generic code U35xx codes Check engine light
What U355C means
U355C reports a circuit fault on the temperature sensor behind the charge air cooler. Compression heats the air strongly: Honda gives about 120 °C at the compressor outlet, while the stack works at 80 to 90 °C, so the air is first brought down to roughly 60 to 75 °C. The sensor confirms this cooling before the air reaches the humidifier. In a Toyota patent it sits between intercooler and humidifier, and if the intercooler coolant pump fails, the controller slows the compressor to keep air temperature below a set limit; Nissan derives an upper pressure limit from the same reading. No maker documents U355C publicly. Without a valid temperature, humidifier and membrane lose their protection, so a warning and a careful cut in power should follow. Pressure here is U355A/U355B.
U355C at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor0.5 to 2.5 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U355C
- Fuel cell system warning, MIL on
- Power limited, especially under sustained high load
- Compressor runs at reduced speed
Common causes of U355C
- Most likelyOpen or short in wiring or connector of the temperature sensor
- PossibleTemperature sensor (thermistor) faulty internally
- Less likelySensor ground or reference circuit faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Cac outlet temperature sensorSensor wiring
What each part of U355C means
| U | Network system: communication between the control modules (CAN bus). |
| 3 | Reserved range, usually generic. |
| 5C | The exact fault in that area. |
What to do next
- Note U355C 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 U355C
What does U355C mean?
U355C means "Charge Air Cooler Outlet Temperature Sensor Circuit". U355C reports a circuit fault on the temperature sensor behind the charge air cooler. It is a generic code, so it means the same on every make.
Is it safe to drive with U355C?
Drive gently and only to a workshop. With U355C the car can go into limp mode (reduced power) to protect itself.
Will U355C fail an emissions test?
U355C 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 U355C to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 2.5 hours of work. This is a job for a workshop.
Will U355C clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.